research report about yoga

A Comprehensive Review of Yoga Research in 2020

Affiliations.

• 1 Advanced Yoga Research Council, AAYM, Germantown, TN, USA.
• 2 Department of Research, Government Yoga and Naturopathy Medical College, Chennai, India.
• 3 Department of Cardiology, NRS Medical College, Kolkata, India.
• 4 Department of Yoga, Central University of Rajasthan, Ajmer, India.
• 5 Department of Yoga, Manipur University, Imphal, India.
• 6 Department of Cardiology, Memphis VA Medical Center, Memphis, TN, USA.
• 7 School of Public Health, The University of Memphis, Memphis, TN, USA.
• 8 Integrative Cardiology, All India Institute of Medical Sciences, Rishikesh, India.
• PMID: 35099279
• DOI: 10.1089/jicm.2021.0420

Objectives: Accumulated evidence garnered in the last few decades has highlighted the role of yoga in health and disease. The overwhelming mortality and morbidity mediated by noncommunicable epidemics such as heart disease and cancer have fostered a search for mechanisms to attenuate them. Despite overwhelming success in acute care, the efficacy of modern medicines has been limited on this front. Yoga is one of the integrative therapies that has come to light as having a substantial role in preventing and mitigating such disorders. It thus seems trite to analyze and discuss the research advancements in yoga for 2020. The present review attempts to distill recent research highlights from voluminous literature generated in 2020. Methods: This review was conducted on the articles published or assigned to an issue in 2020. The authors searched the PubMed database for clinical studies published in the English language, using yoga (including meditation) as the intervention, and having an adequate description of the intervention. Then, they extracted data from each study into a standardized Google sheet. Results: A total of 1149 citations were retrieved in the initial search. Of these, 46 studies met eligibility criteria and were finally included. The studies were predominantly on mental health and neuropsychology, addressing various issues such as anxiety, postural balance, migraine, academic performance, and childhood neglect. Anxiety, stress, and depression were other common denominators. Eight studies were on cardiorespiratory systems, including exercise capacity, cardiac rehabilitation, myocardial infarction, and hypertension. Three studies were on diabetes, evaluating the effect of yoga. Five studies focused on cognition, health status, and autonomic regulation and few others included cancers, infertility, ulcerative colitis, urinary incontinence, restless leg syndrome, rheumatoid arthritis, chronic pain, and metabolic syndrome. Finally, most studies were on noncommunicable diseases with one exception, human immunodeficiency virus; two randomized controlled trials were dedicated to it. Conclusions: Yoga has been studied under a wide variety of clinicopathological conditions in the year 2020. This landscape review intends to provide an idea of the role of yoga in various clinical conditions and its future therapeutic implications.

Keywords: clinical research; meditation; trials; yoga.

Publication types

• Chronic Pain*
• Meditation*
• Mental Health

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Article Contents

Introduction.

• Box 1: Indian philosophical systems
• Box 2: Sankhya philosophy
• Box 3: Yoga sutras

Organization of consciousness

Sense organs, action organs, internal faculties, modulations of mind, sleep as a modulation, attention as a modulation, mind wandering as a modulation, internal states of yoga, internal states, states of samadhi, neural correlates of consciousness, disorders and altered states of consciousness and ytc, loss of cerebellum, damage to prefrontal cortex, split brain patients, predictions, can machines be conscious, qualia through region stimulation, true resting state, ‘viparyaya’, ‘anumaana’ and temporoparietal junction, role of language in intrinsic processing, perturbational complexity index of various modulations and internal states, relation to current theories of consciousness, limitations of ytc, conclusions.

• Box 4: Glossary

Acknowledgements

Conflict of interest statement.

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Neuroscience of the yogic theory of consciousness

Vaibhav Tripathi, http://orcid.org/0000-0001-7520-4188

• Article contents
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• Supplementary Data

Vaibhav Tripathi, Pallavi Bharadwaj, Neuroscience of the yogic theory of consciousness, Neuroscience of Consciousness , Volume 2021, Issue 2, 2021, niab030, https://doi.org/10.1093/nc/niab030

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Yoga as a practice and philosophy of life has been followed for more than 4500 years with known evidence of yogic practices in the Indus Valley Civilization. The last few decades have seen a resurgence in the utility of yoga and meditation as a practice with growing scientific evidence behind it. Significant scientific literature has been published, illustrating the benefits of yogic practices including ‘asana’, ‘pranayama’ and ‘dhyana’ on mental and physical well-being. Electrophysiological and recent functional magnetic resonance imaging (fMRI) studies have found explicit neural signatures for yogic practices. In this article, we present a review of the philosophy of yoga, based on the dualistic ‘Sankhya’ school, as applied to consciousness summarized by Patanjali in his yoga sutras followed by a discussion on the five ‘vritti’ (modulations of mind), the practice of ‘pratyahara’, ‘dharana’, ‘dhyana’, different states of ‘samadhi’, and ‘samapatti’. We formulate the yogic theory of consciousness (YTC), a cohesive theory that can model both external modulations and internal states of the mind. We propose that attention, sleep and mind wandering should be understood as unique modulatory states of the mind. YTC allows us to model the external states, internal states of meditation, ‘samadhi’ and even the disorders of consciousness. Furthermore, we list some testable neuroscientific hypotheses that could be answered using YTC and analyse the benefits, outcomes and possible limitations.

The quest to understand consciousness has been an old one. Questions about our existence, ‘Who am I?’, ‘What is the world?’ and ‘Why is there something rather than nothing?’, have baffled philosophers for centuries. A plethora of philosophical systems were developed in India to answer these questions, which eventually condensed into six orthodox schools and at least four unorthodox schools ( Box 1 ). Sankhya school dealt with the nature of reality broken down into its constituent parts ( Box 2 ). Yoga emerged as a more practical philosophy to realize the true reality and has been practised since the Indus Valley Civilization. The philosophy matured for a few 1000 years when the rules and principles were compiled into the brief sutras by Patanjali ( Box 3 ).

Consciousness as a field of study gained momentum in the Western world when Descartes described the mind–body problem and stated the popular statement, ‘I think therefore I am’. The development of electroencephalogram (EEG) and other medical devices made it possible to record people when they apparently lost consciousness either during sleep ( Borbély et al. 1981 ) or altered their states during anaesthesia ( Akeju et al. 2016 ) or meditation ( Travis and Keith Wallace 1999 ; Baijal and Srinivasan 2010 ). Crick and Koch stimulated an interest in the field with their works ( Crick and Koch 1990 , 2003 ).

The recent development of neuroimaging and stimulation modalities like fMRI, transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) increased the quest to understand our different states of consciousness, and many theories have been developed to allow for better experiments including integrated information theory (IIT) ( Tononi et al. 2016 ), higher-order theories ( Lau and Rosenthal 2011 ), global workspace theory ( Dehaene and Changeux 2011 ), and recent ones like attention schema theory (AST) ( Graziano 2020 ) and dendritic integration theory ( Aru et al. 2020 ; Bachmann et al. 2020 ). Although the current theories offer many explanations for the different day-to-day experiences, they do not discuss or explain away the internal states as experienced during meditation, samadhi or even sleep.

The current theories tackle the question of consciousness as that associated with qualia or experience and try to answer the questions of the kind, ‘What is it like?’. According to yogic thought, consciousness is not just the experience but a fundamental aspect of nature that enables the experience of a being. We formulate a theory called the yogic theory of consciousness (YTC), which is based on sankhya and yoga philosophy. There have been attempts to utilize the postulates of yoga to explain meditation ( Awasthi 2013 ; Nash et al. 2013 ; Aravinda Prabhu and Bhat 2013 ; Bærentsen 2015 ; Raffone et al. 2019 ), which are not applied to the study of consciousness. Other studies have looked at meditation and consciousness ( Raffone and Srinivasan 2010 ; Manuello et al. 2016 ) but were limited to Buddhist traditions and conceptions. Instead of taking the materialistic emergent approach to mind, consciousness and intelligence, sankhya takes a comprehensive approach to the description of the world. Sankhya postulates that the reality is composed of consciousness (‘Purusha’), also called seer, soul, brahman, etc., and nature (‘Prakriti’). The approach is convergent to what some philosophers suggest consciousness being a fundamental property ( Kastrup 2018 ) which forms the basis of experience and it can not be explained as an emergent property of matter ( Chalmers 1995 ).

YTC proposes that mind and seer are separate entities. The mind is emergent in nature, and it depends upon the number and type of sensory data streams an organism can receive (sense organs) and the number of ways it can act (action organs). Tanmatras or the sensitivity and sensory specificity of sense organs separate the individuals within species and across species to have a different percept of the world. The consciousness of an organism includes the role of the sense organs, action organs, mind along with intellect, ego and memory systems which represent the internal faculties, and the seer which is the seat of awareness. YTC can be generically applied to different animals as recent studies have demonstrated that a wide variety of animals including corvids display consciousness ( Nieder et al. 2020 ; Birch et al. 2020 ).

YTC includes the concept of modulations of mind like sleep, memory, mind wandering, perception and inference, which suggests that the mind is aligned with the seer unless the mind is in one of these modulations. Meditation and finer states like ‘samadhi’ can occur when the mind reins in the modulations and becomes aware of the seer. Being established in the seer consciousness has been the goal for self-realization according to the yogic texts.

In this paper, we first introduce the organization of consciousness utilizing the sankhya–yoga philosophies in our YTC model followed by a discussion on the modulations of mind and how activity and connectivity of systems of the YTC model could result in these modulations. We then describe various internal states as experienced during yoga and the finer states of ‘samadhi’ with an explanation of how they can be modelled using YTC and propose some experiments to test such states. We discuss how YTC can explain various disorders of consciousness. We end by listing some predictions we can make using the YTC model and the description of modulations, internal states and finer states. YTC is one of the first theories of consciousness that integrate both internal and external states and can provide testable predictions and experiments to establish these results.

Box 1 : Indian philosophical systems

Indian philosophical system starting with the Vedas illumined in various Upanishads became concentrated in six major schools not necessarily independent of each other. Indian thought was divided into six schools of philosophy—‘Nyaya’, ‘Vaisheshika’, ‘Sankhya’, ‘Yoga’, ‘Mimansa’ and ‘Vedanta’, which highlighted various aspects of reality and the association of living beings with that reality. Other schools of philosophy also emerged in India which did not consider the Vedas as a means of knowledge and were considered unorthodox schools including Buddhism, Jainism, ‘Charvaka’ and ‘Ajivika’.

The ‘Nyaya’ school, one of the oldest schools of philosophy, emphasized the use of logic and reasoning to arrive at any conclusion about the world. The purpose of the senses was to gain knowledge of the world. ‘Nyaya’ school emphasized epistemology or the ways to acquire knowledge about the world. It relied on four out of the six means to gain knowledge (epistemes)—‘Pramaana’/observation, ‘Anumaana’/inference, ‘Agama’/written testimony and ‘Upamaana’/comparison and excluded derivation and negative proof.

‘Vaisheshika’ was expounded by Kanada, one of the earliest atomists. He explained the reality as having different types of ‘padarathas’/categories by which any matter could be understood namely substance, quality, activity, commonness, particularity and connectedness. Kanada also integrates the concept of space, time and mind. ‘Vaisheshika’ also deals with the theories of motion, epistemology, ontology, the description of ‘dharma’, a case for ‘atman’ or soul, and discussions on enlightenment and ‘moksha’ ( Kak 2016 ).

‘Sankhya’ school enumerated and categorized reality in its constituent parts. It was a dualistic school that emphasized that the unmanifest reality (‘Purusha’) interacts with the manifest reality (‘Prakriti’), and upon its interaction forgets its true nature and believes that the purpose of the human existence is to realize the true nature of themselves, which is the ‘Purusha’ and not the creation (‘Prakriti’).

Yoga is the school of practice and illumines the way of realizing ‘Purusha’ being one with our true nature by slowly clearing away the seeds of identification with the ‘Prakriti’ through dedicated practice upon which the false association drops and one gets enlightened and realizes its true nature ( Virupakshananda 1995 ; Shankar and Ravi 2010 ).

‘Mimansa’ school focused on the concept of ‘Dharma’, loosely translated as duty of an individual, and described and studied the ritualistic practices as mentioned in the Vedas.

‘Vedanta’, which translates to the ‘end of the Vedas’, summarizes the knowledge of the Vedas as expressed in various Upanishads which are philosophical discussions on the nature of reality. Badrayana wrote the Brahma Sutras or the Vedanta Sutras which is a terse set of aphorisms that deal with the existence and nature of reality, concept of soul or atman, relation with Brahman, the purpose of life and the theories of cause and effect.

Box 2 : Sankhya philosophy

Sankhya is an enumerationist philosophy aimed at characterization and specification of parts of existence and reality. Sankhya is a dualistic approach to reality where consciousness or ‘Purusha’ along with ‘Prakriti’ exists. The ‘Prakriti’ is manifested as various ‘tattvas’ or part of reality. First being the ‘Mahat tattva’ or intelligence of the nature which abstracts as ‘Buddhi’ or intellect in individual organisms. ‘Ahankara’ separates the reality in the five ‘bhootas’ or elements: air, water, earth, fire and space. And the other aspect of this division is the ‘Manas’/mind which also incorporates memory. This mind develops further into the organs of action, senses and tanmatras. There are five of each. The five tanmatras of taste, touch, smell, sound and sight are associated with the corresponding sense organs tongue, skin, nose, ears and eyes which in turn are associated with the five elements of water, space, earth, air and fire. Three ‘gunas’ or quality rule in the nature: ‘Sattva’ which brings harmony, lightness and balance; ‘Rajas guna’ which is responsible for the activity, change, energy and transformation; and ‘Tamas guna’ which represents dullness and inertia. The five elements are associated, with the ‘prakriti’ being affected by the ‘tamas guna’, and ‘rajas guna’ brings about a transformation in these elements and makes them a part of the mind, sense and action organs which are due to the action of ‘sattva guna’. The ‘gunas’ or quality are associated with different states of the mind and body. These are classified into three: ‘sattva’ causing lightness and balance, ‘rajas’ leading to restlessness, activity, aggression and ‘tamas’ causing dullness, lethargy and inertia.

The goal of the human birth, ‘Sankhya’ postulates, is the end of suffering or ‘dukha’ through breaking the bondage of the ‘ahamkara’ and realizing the true nature of ‘Purusha’ or the seer/soul/atman and not of the ‘Prakriti’ or nature.

Box 3 : Yoga sutras

The ‘Sutra’ or aphorism system of exposition as practised in ancient India was used to summarize the conceptual understanding to as little syllables as possible without being repetitive and being as terse and condensed. The systems allowed easy transmission of knowledge but being terse were prone to incorrect interpretations. The ‘Sankhya’ philosophy is summarized in 72 ‘sutras’ ( Virupakshananda 1995 ) whereas the Brahma ‘sutras’ are expounded in 555 ‘sutras’ ( Vireswarananda 1936 ). Yoga is the practice-focused philosophy aimed at the reduction of misery, increase of joy and eventual enlightenment through realization and being firmly established in the nature of the seer. Misery is attributed to seeds of ignorance (‘Avidya’) or impressions that the subject is different from the world. There are 196 ‘sutras’ divided into four chapters. The first chapter describes the different modulations of mind, internal states, types of ‘samadhi’, and coming to the state of yoga through practice and dispassion. It also lists out some techniques to help a quivering mind settle down when faced by various obstacles. The second chapter talks about the practice in more detail, what to practice and how to practice; it describes the eight limbs of yoga—‘Yama’, ‘Niyama’, ‘Asana’, ‘Pranayama’, ‘Pratyahara’, ‘Dharana’, ‘Dhyana’ and ‘Samadhi’. The state of ‘samadhi’ has many finer nuances explained in the main text. ‘Samadhi’ allows to burn the seeds of ignorance and get established more and more in the true nature of the seer which is bliss, joy and peace.

Chapter three relates to the abilities gained through the practice of ‘Dharana’, ‘Dhyana’ and ‘Samadhi’, and the final chapter talks about the method and the process towards ‘kaivalya’ or enlightenment when the fetters of ignorance or ego have left the mind and it can totally become one with the seer.

According to ‘Sankhya’ philosophy ( Virupakshananda 1995 ), the world is composed of consciousness (Seer/‘Purusha’) and creation (‘Prakriti’) which itself is the total of twenty-four ‘tattvas’ including the sense organs, ‘tanmatras’, action organs, elements, mind, intellect and ego along with memory. In our YTC, we extend this philosophy into a model as illustrated in Fig. 1 which represent the various faculties of each individual. The sense organs bring in data and knowledge about the world, filtered through the ‘Tanmatras’ or sensitivity/sensory specificity of each sense organ (not shown separately but built into the abstraction of the sense organs). The way we have thought of is that sense organs are not just the physical organs of sense but also includes the regions in the brain which are specific to the processing of each sense. For example, the eyes, retinal ganglion cells, lateral geniculate nucleus and then onto the early and late visual cortex are all abstracted as the visual sense organ. The mind composes and interacts with these senses and make decisions based on the intellect subsystem along with memory and ego subsystems and then sends the output signal to the motor organs which form an abstraction including the motor cortex, parts of the cerebellum (for simplicity not included in the figure) and the peripheral nervous system.

Yogic theory of mind and consciousness: A) The organization of consciousness according to YTC. Sense and action organs represent external faculties that enable interaction with the world. In this and subsequent figures, the direction of the arrows represents the flow of information or cause–effect relationship, the width of the connecting arrow depicts the strength of the connection, faded region and arrows represent a temporary reduction in activity and connection, respectively, and a broken arrow represents disconnection whereas red cross represents damaged physical connection. B) Sense organs comprise external senses like taste, touch, smell, sight and hearing, and internal senses like nociception (pain), proprioception, interoception and balance. Tanmatras or sensitivity and specificity of each sense organ is an internal property and not described in the figure here. Brain regions like occipital cortex are considered a part of the sense organ in the YTC, similarly for the somatosensory cortex, auditory cortex and olfactory region. C) Action organs of movement, hold/grasp/push, speech, excretion and procreation are represented in the motor cortex which is considered part of the action organs in YTC. D) Internal faculties of the intellect, ego and memory interact through the mind. The mind constitutes the default network and the attention network (not all regions of the networks are represented in the figure). The intellect is represented in the prefrontal cortex also called cognitive control network (which includes frontoparietal control network; not all regions are represented in the figure) and the ego (self-referencing) in the medial prefrontal cortex (mPFC). The hippocampus and amygdala are the regions associated with memory. All these faculties working in conjunction perceive, cognize, think, remember and act. Seer, separate from the others, is the centre for awareness.

As compared to the ‘Sankhya’ model described in Box 2 which refers to the twenty-four ‘tattvas’ related to external sense perceptions in humans, we have also included the internal sense organs in the YTC model. And our abstraction can be generalized over different species of animals and not just humans. Although we have not shown subcortical regions in the representations on Fig. 1 , they are assumed to be a part of the sense organs. We look closely at each individual system in the sections below.

We perceive the external world through the five senses of touch, taste, sight, smell and sound and the internal world through nociception, proprioception, balance and interoception. The sense organs as abstracted in the YTC model are not just the sensory receptors but composed of the whole hierarchical processing involved, including the receptors, ganglion cells and peripheral nervous system, to the thalamus and the brain. For the visual sense, higher areas like the V4/V8, medial temporal (MT) and intraparietal sulcus are also included. Similarly, for the auditory sense, ears, cochlea and thalamus up to the auditory cortex are all abstracted in the model.

The concept of ‘Tanmatras’ is unique to ‘Sankhya’ and represents the subtle dimension of the senses. The idea of ‘tanmatras’ has been unexplored in consciousness sciences and in our model, we consider ‘tanmatras’ as composed of two aspects: specificity and sensitivity of a sense organ. Sensitivity refers to the range of sensory data to which the sense organ can respond, e.g. humans have a hearing frequency of 20 Hz to 20 kHz and dogs have a sensitive olfactory sense with up to 40 times more receptors than humans ( Porter et al. 2007 ; Craven et al. 2010 ). Specificity determines the amount of sense data required to trigger a conscious perception of that sense. The sensitivity and specificity which determine the corresponding ‘tanmatras’ can change across species and even within individuals of the same species. Specificity of sense organs would depend on modulations (explained in the following section) including attention, inference, mind wandering and sleep. Attention has been shown to modulate perception ( Carrasco et al. 2004 ; Ling and Carrasco 2006 ) via amplification of signals specific to a sensory type, time and location.

The organs of action include the limbs, speech, organs of excretion and procreation and also all the muscular movements that can be done consciously. From the motor cortex to the peripheral nervous system, the regions responsible for motion or movement are a part of the organs of action. Although we have not shown the cerebellum in Fig. 1 , it is an important part of the process of action even though the absence of it ( Yu et al. 2015 ) has not shown much difference in cognitive abilities but only slightly impaired motor functions.

The mind is a subsystem of the internal faculties. Along with intellect, ego and memory system, it works in close conjunction to create a continuity of perception and aids in planning, cognition, sensory integration and intention to move. Mind is the higher-order region that can deploy attention through the dorsal attention network (DAN) to amplify signals from the sensory systems to gain more knowledge of the world or it can go into mind wandering, imagination and thinking about the past and the future. Mind is the central system when we expect someone to be conscious. A lot of published studies interpret consciousness as the mind but yogic texts separate the mind from the other faculties. The mind assumes the form of its contents and when engaged with the outside world (scenery), it forgets the awareness of the seer. Desires arise in the mind along with the myriad of thoughts, intuition and creativity. It is affected by the modulations and loses track of the seer in the process. Yoga sutras point out that the time spent in modulations by the mind prevents it from completely experiencing the reality in the present moment now. All the practices and teachings of the yoga philosophy are aimed at reducing these modulations of the mind and removing the seeds or impressions in the memory which cause the mind to go into these modulations again and again. Through consistent practice of the eight limbs of yoga, the modulations of the mind get more and more restrained, which result in better concentration, an increase in joy and the feeling of oneness with the world.

The mind is best represented as composed of the default network [posterior cingulate cortex, temporoparietal junction (TPJ) and temporopolar cortex] and the attention network (parietal cortex and frontal eye fields). A lot of studies assign the seat of consciousness as the posterior parietal cortex ( Koch et al. 2016 ) but we argue that instead it is the seat of the mind. The research paradigm that is targeted to the study of the seer actually studies the mind.

According to YTC, the development of mind is closely linked to the number and type of sense organs, their associated ‘tanmatras’, and the number and type of action organs. Organisms with different sense organs, action organs and ‘tanmatras’ will have a ‘different’ or ‘unique’ internal faculties. The mind of a dog that has a different ‘tanmatra’ for olfactory sensations would have different mental processes than humans or even dolphins which could sense bands of electromagnetic waves that we cannot. The mind is unique to every organism and we should not expect direct correlations in the neural processing and signatures across species until we fix the three—sense organs, action organs and ‘tanmatras’. We should expect to see conserved principles across species but any cross-species analysis should not be wildly extrapolated. The development of the mind across species can be an important step in understanding the limits of conscious processing.

The intellect subsystem is a part of the internal faculties and is related to decision-making, filtering thoughts that come up in the mind and are represented by the Cognitive Control Network.

Memory subsystem centred in the hippocampus and amygdala is associated with memory formation but there are evidence of the wide-scale cortical involvement in long-term memories. A ton of work have been done in this field with regard to the actual dynamics of memory formation, extinction, affect-based memories, spatial memories, etc. ( Gabrieli 1998 ). In our model, memory holds the information for any event. It is also related to one of the modulations of the mind; when the connectivity between the mind (default network) and the memory region is high, the mind spends a lot of time thinking about the past.

Ego subsystem is associated with self-referential processing, risk-taking and centred around the mPFC. Many studies put it as a part of the default network ( Christoff et al. 2016 ) but it is closely linked with the mind, intellect and memory. Damages to this region have shown reduced risk aversion ( Spaniol et al. 2019 ). We further hypothesize that increased connectivity between the ego and default subsystems could be linked to narcissistic personality traits.

Seer is the finest aspect of consciousness and represents the seat of awareness. It perceives the world through the mind which is affected by modulations. Yogic texts relate to it as the source of conscious awareness, joy and happiness. Self-realization or ‘kaivalya’ is found when the practitioner becomes totally aware of the seer through the reduction of memories and modulations. Indian philosophers consider the realization of the seer as one of the most important goals of life ( Shankar and Ravi 2010 ; Vivekananda 2018 ). We are of the thought that current neuroscientific research has looked into the aspects of the mind and the modulations of the mind but has not investigated the neural correlates of the seer. Research into the meditation techniques especially where the modulations do not exist in the mind (‘Nirvichara/Nirvikalpa Samadhi’) can show a better understanding of the seer.

The purpose of yoga as a practice is to silence the modulations (‘vrittis’) of the mind so that the mind can be established in the seer. These modulations can be either painful or not. When the modulations are active, the mind is engaged with the scenery (sense organs or knowledge related to sense organs). Yoga sutras ( Hartranft 2003 ; Shankar and Ravi 2010 ; Vivekananda 2018 ) propose the presence of five modulations: proof or means of knowledge (‘Pramaana’), wrong understanding of knowledge (‘Viparyaya’), imagination (‘Vikalpa’), sleep (‘Nidra’) and memory (‘Smriti’). ‘Pramaana’ or means of knowledge can be of three types as accepted in the sankhya and yoga philosophical schools: perception/‘Pratayksha’, inference/‘Anumaana’ and documented evidence/‘Agama/Shabd’. ‘Pratyaksha’ means gaining knowledge through the sense organs directly, ‘anumaana’ means making an inference on the information captured through the sense organs and ‘shabd’ means utilizing the evidence documented by an authentic source. An example is cited in many Indian philosophical texts to describe the three: consider being in a forest, and you see smoke—you infer that there should be a fire nearby (‘Anumaana’/Inference). As you go nearer, you visually confirm the presence of fire (‘Pratayksha’/Perception). You know from knowledge gained from experience or documented evidence (‘Shabd’) that covering the fire up can extinguish it by cutting the oxygen source. The means of knowledge takes the mind away from the seer and thus engaged in the scenery. The other modulations ‘Viparaya’ is wrong knowledge not based on the true form of an object. Example: You cross the street and a few people start laughing and you think to yourself if they were laughing at you? ‘Vikalpa’ or imagination follows from word and knowledge of the word but devoid of any object. Memory (‘smriti’) or remembering the past, reliving the experiences from the past, or thinking about events from the past which do not exist now is also considered a modulation of the mind along with sleep/‘nidra’ where the mind has no content ( Hartranft 2003 ; Shankar and Ravi 2010 ; Vivekananda 2018 ).

Sleep has been understood to be a state of consciousness where there are no contents of the mind yet sleep research have depicted that it is a very active process, from waste clearance by the flow of cerebrospinal fluid (CSF) ( Xie et al. 2013 ) and sleep spindles ( Ujma et al. 2020 ) to memory consolidation via neural slow waves. Both the processes were found to be related ( Fultz et al. 2019 ) recently. Papers have proposed that local sleep can occur during wakefulness and may be responsible for attentional lapses ( Andrillon et al. 2019 ). The yoga sutras classify sleep as a modulation of the mind which not only occurs once or twice during the day/night for an extended period but also small short bursts or local periods of sleep. We argue that sleep is not a different state of consciousness but a modulation of the mind. It is a physical process required by the body to carry out maintenance activities but expert meditators and yogis have been suggested to reduce the need for sleep through years of practice ( Kaul et al. 2010 ). The research is lacking in this domain as only recently scientists have started to piece together the importance of sleep in our lives ( Xie et al. 2013 ; Fultz et al. 2019 ) but how yogic practice can reduce the need for sleep needs to be studied carefully. We also propose that local sleep and extended sleep during the night time would have similar characteristics in terms of neural patterns especially in the mind subsystem [default network (DN) and DAN regions]. We describe the rapid eye movement (REM) and deep dreamless non-REM states using YTC in Fig. 2 .

Sleep as a modulation of mind: our model argues that instead of understanding sleep as an altered or different state of consciousness, it should be thought of as a modulation of the mind where A) the mind either has no content (deep dreamless sleep), the connections with the sense and action organs are reduced and the internal faculties have decreased communication with each other and also have reduced activity. B) REM phase of sleep involves vivid dreams and occurs every 90–120 minutes where memory consolidation happens along with CSF recycling ( Fultz et al. 2019 ). In our model, the mind and the memory subsystems are strongly connected during the REM phase with some activity in motor organs and possibly some in the visual regions.

Attention has been researched extensively over the last few decades. Attention has been shown to alter perception ( Carrasco et al. 2004 ; Ling and Carrasco 2006 ) by amplifying the signals at the focus of attention and attenuating other signals. Yoga sutras consider attention as a means of gaining information and knowledge about the world which in turn alters our perception of the world ( Carrasco et al. 2004 ). Attention is thought of as a modulation of the mind as it takes the mind away from the seer which is the source of awareness to the scenery. Attention modulates the content of the mind. Yoga texts have described the role of attention in practices like ‘dharana’ and ‘dhyana’ and suggest that intense attention to any one of the sensory streams reduces all other modulations of the mind and the mind becomes alert and focused. Awareness and attention are often confused. We believe that attention is a process of the mind regulated with the DAN and required dedicated resources from the brain, and engages effort so much so that people prefer pain over attending for long durations or harder tasks ( Vogel et al. 2020 ). However, awareness is the property of the consciousness in general and seer in particular. We are always aware and only during the times of modulations our awareness reduces. Awareness can also be thought of as salience and may have possible correlates in the ventral attention or salience network.

We set our mind to a task at hand, maybe reading this paper or doing some analysis and the mind starts to drift and some thoughts come up of the past and some imaginations about the future, we may think about what someone said or imagine what would one do in a situation if it shows up. We all have observed the mind wandering but the awareness of the wandering mind comes after the mind has gone off for some time. We suddenly realize that we have not done anything or probably missed out on some parts of the conversations with someone. YTC considers mind wandering as a modulation composed of ‘Vikalpa’ or imagination which could be constrained or spontaneous. It is separate from ‘Smriti’, which is a remembrance of events, and from ‘Viparyaya’ where the mind perceives and infers incorrectly. There have been recent attempts to study mind wandering ( Smith et al. 2001 ; O’Callaghan et al. 2015 ; Christoff et al. 2016 ; Schacter et al. 2017 ; Scheibner et al. 2017 ) but still, it is in its nascent stage. Current neuroscientific research on the mind wandering contextualize thoughts either generated spontaneously or deliberately and with constrained focused towards a task at hand ( Christoff et al. 2016 ). Frontoparietal control network can exert deliberate control over the thoughts but spontaneous thoughts are generated in the middle temporal lobe (MTL) subsystem of the DN. The core network of the DN comprising posterior cingulate cortex and posterior inferior parietal lobule automatically constraints the thoughts related to the individual. The activity of the brain during wakeful rest is found to be in two prominent states ( Karapanagiotidis et al. 2020 ), which correspond to the modulations of memory (‘smriti’) and imagination (‘vikalpa’).

Mind wandering is usually thought of as noise in the mind and behaviourally estimated out using reaction times and accuracy on task. But such experiments and studies ignore the state of mind wandering, an important aspect of the mind. When we understand that mind wandering and attention are modulations of the mind (as illustrated in Fig. 3 ), it can help us design better behavioural experiments. Although the study of mind wandering is dispersed and there are no cohesive methods to detect when the mind wandered without probing ( Weinstein 2018 ), we believe that full neural correlates of consciousness would include both the neural correlates of attention and mind wandering.

Mind wandering and attention as modulations of the mind: A) When the mind is engaged in the memory or the remembrance of the past events, the sensory data are unattended to and the mind engages strongly with the memory system, and the connectivity with the seer is reduced. B) During imagination or vikalpa, a word or a thought in the mind starts a stream of self-referential processing involving the ego and the intellect subsystems with sensory data unattended and awareness from the seer reduced. C) During wrong knowledge of a percept, the connectivity with the intellect, memory systems and sense organs is increased whereas it decreases with the seer subsystem. D) Sensory attention or perceptual proof (Pratayksha Pramaana) where the connectivity between the mind and the seer decreases, and the mind engages with the outside world through the sense organs, increasing the sensitivity and specificity of the incoming sensory signals, and the signals from the memory regions are also reduced.

The different states of mind and consciousness according to YTC are listed in Table 1 . When the mind is not in the five modulations, it is not seeking knowledge about the world and is not engaged in self-referential processing, imagination, incorrect knowledge, sleep or memory, it is said to be in the state of yoga. There are further states of ‘dharana’, ‘dhyana’, ‘samadhi’ and ‘samapatti’. The state of ‘samadhi’ is further divided into ‘sabeeja samadhi’ and ‘nirbeeja samadhi’. The latter is experienced after years of practice and is considered a goal for yogis and practitioners but the former has nuances and subtle states within it. We would look closely at each of these states and how YTC can model and experimentally investigate them. Buddhist literature also mentions the state of ‘Jhanas’ ( Hagerty et al. 2013 ) or ‘dhyana’ in Sanskrit which are probably close or similar to the states described here as mentioned in the yoga sutras ( Flood 2013 ; Rose 2016 ). A meta-analysis found some differences ( Tomasino et al. 2014 ) between the states but additional neuroscientific evidence is warranted to compare the different traditions objectively.

The different states of mind and consciousness.

‘Pratyahara’ is the process of taking the attention and the mind from the external sense objects to internal senses like proprioception and interoception which allows the reduction of modulations and serves as a process to go into the finer and less perturbed states of ‘dhyana’ and ‘samadhi’.

‘Dharana’ (concentration) is another internal state where through taking attention to a fixed location the modulations of the mind are reined in. Different yoga and meditation practices have used various methods for ‘dharana’ including attention to parts of the body, specific locations such as ‘chakras’ or ganglions, sensations of the body, attention to breathing, unbroken attention to a point (‘trataka’), repeated chanting/‘japa’, etc. ( Deepeshwar et al. 2019 ). All the subsystems of the mind and consciousness are active with attention to internal or external sense organs and the modulations begin to reduce. Attention regions are active along with amplification signals to one of the senses. Default mode activity has reduced and disconnects with the attention network.

‘Dhyana’ or meditation is the state achieved when the modulations have reduced, with only one content of mind which is continuous and not changing. There is no impulse to act, the connection with the action organs is reduced and other systems are active but the mind is coming back to a singular content. We can think of it as an attractor state of a dynamical system ( Bærentsen 2015 ). The attention network is still active but the amplification of the sensory signals have decreased. The default mode system has reduced activity and decreased connectivity within the network and with attention network ( Nash et al. 2013 ; Raffone et al. 2019 ). Thalamocortical signals from the multiple demand regions of the thalamus have reduced the firing rate in the cortex ( Aru et al. 2020 ; Bachmann et al. 2020 ). Alpha and Theta power increase in deep states of meditation ( Travis and Keith Wallace 1999 ; Baijal and Srinivasan 2010 ) and hemispheric band power synchronizes ( Bhaskar et al. 2020 ).

‘Samadhi’ is staying in the state of ‘dhyana’ long enough that the content of the mind disappears; there can be thoughts, some logic, feelings of bliss and joy, and sense of I-ness but the mind has no continuous content. It is an equanimous state where there are no modulations: mind wandering, memory or sleep. Default mode activity is low and disconnected, the attention network activity has also reduced and the sensory signals are attenuated.

‘Samapatti’ is a trait feature that is achieved after practice for many years: perception of the world is clear and the mind does not wander, there is no local sleep and affective stimuli do not create strong memories (PYS 1.41). Experienced meditators and yogis stay in the state of samapatti where the default mode activity and connectivity with valence regions and memory regions are reduced. ‘Asana’ or posture practice can also bring in a temporary state of ‘samapatti’ (PYS 2.47) wherein putting effort and letting go takes the mind temporarily to the state of ‘samapatti’. We have demonstrated in Fig. 4 how these internal states would be modelled by YTC.

Description of the internal states according to the YTC: A) Pratyahara translates to giving alternate food to senses; the attention is drawn from all the external senses to internal sense perceptions. B) Dharana or concentration is a practice to take attention to an object, a sensation in the body, a repeated word or mantra, but with a singular focus on one object or location, the signals to which the mind then amplifies. C) Dhyana or meditation happens when the modulations start subsiding and the intellect and memory become less connected to the mind. The content of the mind is singular and continuous. D) Samadhi or transcendence is an equanimous state where the mind drops the content it is holding onto during dhyana, modulations have subsided and focused onto the seer (aware of simply being), and the inputs from sense organs are still coming but not changing the content of the mind. E) Samapatti is a state of being aware of both the seer and the scenery; modulations are subsided and impressions or memory not active as not many associative memories are formed.

‘Samadhi’ has multiple nuanced states as mentioned in Table 1 and illustrated using YTC in Fig. 5 . We can first describe two types of ‘samadhi’

Description of the finer states of Samadhi: A) Sampragayat Samadhi: state of samadhi or equanimity with awareness wherein sensory activity decreases, spontaneous thoughts arise, some logic about the mind and body can form and be accompanied with the feeling of elation and joy with a sensation of ‘I am experiencing’ or ‘I am being’. B) Pragyapoorvak Samadhi: a state that comes after awareness and can be invoked using memory of an event, valour or faith. Runner’s high, deep religious and spiritual experiences come under this classification of Samadhi. C) Nirvichara Samadhi is a state similar to (A) but without spontaneous thoughts, and similarly a state is called Nirvitarka Samadhi which does not involve any logic in the mind. D) All these states of samadhi come under Sabeeja Samadhi which means a state of equanimity where the memory, impressions and seeds are still active whereas Nirbeeja Samadhi is a state that one goes beyond the limits of the mind and memory and is free from any impressions or seeds, also called as state of enlightenment of Kaivalya where only the seer remains and the feeling of oneness with the whole creation is observed.

‘Sabeeja Samadhi’: The states of ‘samadhi’ with the seeds of ignorance; they are further divided into

‘Sampragyat Samadhi’: State with awareness where one can observe spontaneous thoughts, special logic about oneself, feeling of bliss and joy and the mind is established with the seer, it is further divided into

‘Savichara’: with spontaneous thoughts, we propose that in such a state, the MTL subsystem of DN would be active.

‘Nirvichara’: without spontaneous thoughts and no firing of the DN–MTL subsystem.

‘Savitarka’: with special logic, frontoparietal network and cognitive network would be active and connected with default network.

‘Nirvitarka’: without special logic, frontoparietal network would be inactive and disconnected.

‘Asmita Arupa’: with a feeling of I-ness, the mPFC would be active with connectivity with default and attention regions.

‘Anand’: with feelings of bliss and joy.

‘Pragyapoorvak Samadhi’: The states of ‘samadhi’ which are reached by being aware and in the state of action where the mind spontaneously drops off the modulations and becomes one with the seer.

‘Shraddha’: a spontaneous state of ‘samadhi’ reached during intense periods of religious or spiritual activity.

‘Veerya’: When valour is invoked, it brings in about a spontaneous state of being aware of the self and the seer.

‘Smriti’: Memory of a deep experience of ‘samadhi’ can itself take one into samadhi.

‘Prakriti Laya’: When we see a beautiful sunset across the ocean and the mind totally settles in, for brief moments ‘prakriti laya samadhi’ occurs, which translates to being in unison with nature.

‘Nirbeeja Samadhi’: The state of samadhi where there are no seeds of ignorance left and the modulations of mind have ended; the individual is totally one with the creation ‘kaivalya’ or enlightenment is experienced.

How and why we have any experience is expressed as the hard problem of consciousness ( Chalmers 1995 ). How could matter come together and form experiences is still unclear. The materialist perspective postulates that consciousness should be an emergent property which develops out of the complex computations in the billions of neurons that the human brain possesses. But, the recent studies on corvids ( Nieder et al. 2020 ) and other animals ( Birch et al. 2020 ) suggest that animals with an entirely different and much smaller brain structure can still possess consciousness. Either different number and configurations of neurons can bring together a similar emergent property or the circuitry required to bring emergence is not as complicated.

YTC considers consciousness to be a fundamental property of life but the mind to be an emergent process out of configuration of the sense and action organs. Higher-order processes involve the intellect, ego and memory subsystems (represented in the cognitive control system, mPFC and hippocampus) along with the mind. As different species possess different attributes of intelligence, sense and action organs, we can expect their internal faculties to have different properties as compared to humans like corvids engage nidopallium caudolaterale in higher cognition ( Nieder et al. 2020 ) whereas mammals utilize PFC for intelligent behaviours. The separation between the neural correlates of consciousness and neural correlates of mind and other internal faculties can help us understand the specific role of these faculties to create a cohesive cognitive unit.

Then, what are the neural correlates of consciousness? According to our model, the seer is deeply integrated with the mind. Any study that can help us understand the seer or the seat of consciousness (according to the yogic model) and determine its physical correlates will be limited by the state of the mind. If we have the neuroscientific correlates of all the states of the mind, then when the mind is switched off, it can help us detect the physical correlates of the mind without the confounds of the mind. Two processes of Nirbeeja Samadhi and general anaesthesia switch off the mind, and neuroscientific and biological signatures of these states can help determine the physical correlate of the seer. General anaesthesia although easy to administer causes chemical-based increase or decrease in Gamma-Aminobutyric Acid (GABA) or N-methyl-D-aspartate (NMDA) receptors, whereas ‘Nirbeeja Samadhi’ comes through years of training and thus is more natural and would involve long-term changes in the brain that can sustain the state closest to pure awareness and not affected by the modulations and activity of the mind.

Accidents, injuries or disorders can cause altered states of consciousness. Traumatic brain injury, coma and locked-in syndrome are some of the conditions that can cause a different than normal consciousness ( Bayne et al. 2020 ). Local anaesthesia can totally remove the pain ( Purdon et al. 2015 ). General anaesthesia can cause total blankness and the subjects do not even recall how much time has passed in such a state ( Brown et al. 2018 ). There has been no concrete solution for this aspect from the theoretical standpoint. Here, we argue (as illustrated in Fig. 6 ) that under these two mechanisms of reduced integration between the systems, either the activity in a system is reduced or the systems are disconnected. Using perturbational complexity index (PCI; Casali et al. 2013 ), which uses TMS along with EEG, we can test the integration between the various subsystems of YTC model as stated in Fig. 1A . Locked-in syndrome causes the disconnect with the action organs and the patient is unable to move any part of the body other than the eyes. Coma results in the decrease in the amount of sensory information coming in to the patient but totally disconnected action organs. Local anaesthesia results in the disconnection of nociception in specific parts whereas general anaesthesia causes a reduction of integration across systems but with local neuronal activity within networks.

Explanation of disorders or altered states of consciousness using the YTC model. A) Locked-in syndrome is represented by the lack of motor movements but the subject is conscious; we propose that the connection with the motor organs is severed, resulting in a conscious and aware subject with no movement. B) Comatose patients have been shown to have a degree or level of consciousness of sensory percepts although they cannot move. In our model, we suggest that there is a disconnection with the action organs and reduced connections with the sense organs; some senses might be more damaged than others. Although there are different types of coma, we represent here a case where there is no damage to the internal faculties. Some other forms of coma, resulting from injury, built up of toxins and irregular functioning of the internal faculties of mind, intellect, ego and memory, may have a range of symptoms and corresponding relation to the level of consciousness. C) General anaesthesia using chemicals like ketamine and propofol has been researched extensively; we hypothesize that the sense, action organs and the internal faculties are all shut in the sense that there is no long-range communication across the subsystems and activity is reduced within the subsystem. D) Local anaesthesia results in the temporary disconnection with the specific sense organs including the sense of pain (nociception) which results in reduced signals from the sedated part of the body.

Cerebellum has always been thought to be related to motor processing but recent studies have started to find more involved role in cognition ( Brissenden et al. 2016 ; Bostan and Strick 2018 ). Researchers have argued the specific contributions of the cerebellum to consciousness. A subject was found to be living healthily without a cerebellum with only minor motor problems ( Yu et al. 2015 ). In our model, cerebellum is not included in the internal faculties and hence play no specific role in the mind, intellect, memory, ego or as the seer. We might need to include the cerebellum as the exact function of it becomes clear. It might be involved in the intellect network, the mind network or the ego network separately as some functional connectivity studies have suggested ( Buckner et al. 2011 ). More work is required to establish the exact role of the cerebellum in motor, cognition and consciousness.

The case of Phineas Gage has depicted the role of PFCs in behaviour and self-control. As the intellect and ego network are found in the frontal regions, according to YTC, we posit that the mind of such a person would be intact but the intellect and ego faculty would be damaged and can cause changes in personality and make the patient unable to do various cognitive tasks.

Corpus callosotomy, or separation of the two hemispheres of the brain, has been used as a treatment for severe cases of epilepsy. It results in very peculiar observations like when an object is placed on the left visual field of a patient, it can detect the object and even draw the object using the left hand but cannot say it out loud as the left visual field is represented on the right hemisphere of the brain which in turn does not communicate with the left hemisphere which is related to speech and vocalization. For such cases, using the YTC model, we suggest that the mind subsystem would be its.

YTC provides us a tiered model of understanding the external world, internal faculties which perceive and act upon the world, and the innermost faculty or the seer which is aware of the world. The concept of bringing together the modulations of the mind along with inner states of meditation and yoga can provide a better interpretation of various phenomena.

According to ‘Sankhya’ philosophy the world including the action organs, sense organs and the internal faculties are emergent properties of the nature. As our devices become more and more complex with increasing levels of abstraction, it would be possible to create machine analogues of sense organs and motor organs. Recent advances in deep learning (DL) has allowed high-performing visual systems which can be extended to other sensory systems as well. The progress in robotics, bio-inspired prosthetic and brain–computer interfaces can allow us to replicate our motor functionalities better. DL has already conquered the field of computer games with systems like AlphaGo and AlphaStar ( Silver et al. 2016 ; Vinyals et al. 2019 ), so it is quite possible that the intellect network could be created. Other aspects of ‘Prakriti’ like the mind, memory and ego technically could be machine replaceable given in the coming decades we understand the dynamics of these networks across species. As the seer is the fundamental aspect of reality, a machine analogue is not possible but hybrid systems can have the possibility of consciousness according to the Sankhya understanding.

A persistent question that has been asked to the different theories of consciousness: ‘Why are qualia invoked when specific brain regions are activated?’ ( Balduzzi and Tononi 2009 ) Stimulation through TMS or tDCS to frontal eye field region, MT, V4/V8 and other regions can invoke the qualia for faces, motion and colour, respectively ( Valero-Cabré et al. 2017 ). According to the YTC-based organization of consciousness, these regions are a part of the sense organs. Hierarchical processing enables regions to be receptive to certain features more than others. Activation through techniques like TMS or tDCS, perpetuate signals downstream which could otherwise come from the subsequent sense organ. We can further extend this to suggest that a similar kind of stimulation of processing regions in the auditory or somatosensory regions can invoke qualia of various features of sound.

Serendipitous discovery of the default network activation in the brain during no task condition ( Raichle et al. 2001 ; Gusnard and Raichle 2001 ; Buckner et al. 2008 ; Buckner and DiNicola 2019 ) created a whole field of neuroimaging known as resting-state functional connectivity ( Fox et al. 2005 ). It led to the development of biomarkers for different conditions like Parkinson’s and attention deficit hyperactivity disorder ( Sørensen et al. 2016 ). Still, after 25 years of the discovery, the actual cause for the default network activity during resting state and its anticorrelations with the DAN ( Fox et al. 2005 ) has not been found. Recent attempts discover the role of high-cofluctuation activity being responsible for the connectivity patterns during resting state ( Esfahlani et al. 2019 ). Other approaches have signified the role of intrinsic processing and mind wandering for the activation of the default network ( Christoff et al. 2016 ). But we truly do not know the reason behind the default activity of the brain.

Understanding the modulations of the mind as specified in the YTC can help us detect a true resting state which would be free of imagination, mind wandering and other modulations. We predict that in such a state the overall default mode network activity would be reduced as compared to ‘normal’ resting state and explicit intrinsic processing paradigms ( Andrews-Hanna 2012 ).

The TPJ has been found to be involved in theory of mind (TOM) ( Saxe and Kanwisher 2003 ) and has been termed as the ability to think what the other person is thinking. The modulation of Viparyaya or incorrect knowledge is closely associated with TOM. Engaging in the thought of what the others are thinking is inference. As recent studies have suggested the role of TPJ in prediction ( Koster-Hale and Saxe 2013 ), we hypothesize that tasks that can invoke ‘viparyaya’/wrong knowledge about an object or ‘anumaana’/inference about some non-perceptual object should activate the TPJ.

Yoga sutras specify the role of language, and the understanding of language as a precursor to imaginative thoughts, unconstrained thinking and mind wandering (PYS 1.9). We propose that tasks that invoke the language regions would have effects on the default network. The connectivity between the language and default network would be predictive of cognitive health; the higher the connectivity, the more the mind would be prone to mind wandering and vice versa. The connectivity differences between the language and default mode network can be found in meditators as compared to non-meditating healthy controls. Bilingual and multilingual people might have differences in connectivity between these regions as compared to monolingual people.

Casali et al. (2013) devised the PCI ( Casali et al. 2013 ) which utilizes activation using TMS followed by detection of brain waves using EEG to find if perturbation of a brain system causes changes in the activity of the stimulated region. We propose that the different internal states of ‘dhyana’, ‘dharana’, ‘samadhi’ and different types of ‘samadhi’ as stated in Table 1 would have different PCI values and EEG-based brain states.

YTC can work well in conjunction with the current theories of consciousness. The integrated information theory (IIT) ( Oizumi et al. 2014 ; Tononi et al. 2016 ) lays down axiomatic rules of how information integrates and determines through complex computations the amount of consciousness in each system ( Koch et al. 2016 ). The sense organs in YTC integrate sensory information across multiple modalities and hence, YTC can implement IIT. IIT is limited in its perspective as it does not take into consideration action organs. Evolutionarily, the purpose of consciousness should not be only the integration of information but also planning and movement. From the bottom up, it would be hard to prove or disprove IIT in its current shape but extended format coupled with YTC can give it a lot of power. YTC also incorporates the concepts of higher-order theories ( Brown et al. 2019 ) and global workspace theory ( Dehaene and Changeux 2011 ) in the sense that the internal faculties of intellect, memory and ego are higher-order regions which interact with the mind which integrates information from the senses and composes and relays movement onto the action organs. The thalamocortical theory or the dendritic integration theory ( Aru et al. 2020 ; Bachmann et al. 2020 ) provides the framework of the integration between the sense organs through the thalamus and the mind network. Although some parts of the AST ( Graziano 2020 ; Graziano et al. 2020 ) especially the portrayal of the seer as just a schema to aid in attention does not fit with the YTC but the generation of schemas of attention as a modulation integrates well with YTC.

YTC as a theory does not focus on the phenomenology aspect of consciousness. All conscious percepts are considered as contents of mind derived from the sense organs with specific ‘tanmatras’. The theory also does not consider aspects of affect and emotion.

We present a neuroscientific perspective of the YTC as presented in the yoga sutras of Patanjali and the ‘Sankhya’ philosophy. From the first person perspective, reality is classified as ‘Purusha’ and ‘Prakriti’ [composed of the ego, mind, intellect, sense organs, action organs, subtle sense dimensions (‘tanmatras’) and elements]. The ‘Purusha’ is the seer or self or the consciousness, and the mind interacts with the world through the organs of action and perception. We present that the development of the mind depends on the number and type of sense and action organs and the ‘tanmatras’ (sensory specificity) which can allow us to better model mind and consciousness of other species. We also suggest that species specific findings may not be generalizable.

The mind acts as a gateway to the perceived world for the seer. The mind has modulations like attention, inference, memory, sleep, imagination and wrong knowledge which alter perception, and thus the conscious awareness of the percept. Attentional modulations affect perception and the content of the mind is enhanced at the cost of non-attended stimuli. Active-inference-based modulations affect our sensory signals as well as motor responses. Mind wandering through imagination, wrong knowledge and memory modulates the intrinsic and self-referential processing at the cost of extrinsic modulations and in turn affects consciousness.

The practice of yoga is having a say over these modulations and truly ‘perceive’ our consciousness. Modern scientific literature on meditation has suggested the presence of unique neurobiological signatures for such states. We elucidate the different states of mind like ‘Dhyana’, ‘Dharana’ and ‘Samadhi’ and characterize them which can help improve current approaches to neuroscience of yoga and meditation. Our specification of the internal and external states of mind can better our understanding of the neural correlates of consciousness.

Our theory is one of the first to integrate the aspects of organization, evolution and development of mind, modulations of mind and how it affects perceptual consciousness, and intrinsic states of meditation in a cohesive structure. YTC is an overarching theory and works in conjunction with the current neuroscientific theories of consciousness which addresses specific parts of the understanding of mind and consciousness.

Box 4 : Glossary

‘Sankhya’: Enumerationist Indian philosophical system which breaks down the reality in its constituent parts.

‘Yoga’: Indian philosophical school associated with the practice of achieving enlightenment and taking over the illusion of the mind relation with the scenery.

‘Tanmatras’: Subtle sense organs which can be thought of the combination of range of each sense organ in terms of physical reality it captures (for a species) and the specificity of sense organs (for each individual).

‘Mann/Manas’: Mind.

‘Buddhi’: Intellect, an individualized abstraction of Mahat which is the intelligence of the nature.

‘Ahankara’: Ego sense which gives the illusion of separation of one individual from the other.

‘Samadhi’: State of equanimity with or without perception.

‘Samapatti’: State of equanimity with perception.

‘Chitta’: Individualized consciousness comprising the intellect, ego, mind and memory.

We acknowledge the teachers and philosophers who contributed to the Indian philosophies and their unpublished lectures and commentaries which could not be referenced here beginning with Gurudev Sri Sri Ravi Shankar, Maharishi Patanjali, Adi Shankara, Maharishi Vyasa and Swami Vivekananda amongst others. All figures were created using BioRender.

Partial Article Processing Charge support was provided by MIT Libraries Open Access Fund. No other funding was received for the project.

None declared.

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Current Issue

Volume 5 (2024) of the Journal of Yoga Studies.

ISSN: 2664-1739 DOI:  https://doi.org/10.34000/JoYS.2024.V5

The  Journal of Yoga Studies (JoYS)  is a peer-reviewed, open access e-journal committed to publishing the highest quality academic research and critical discussions on all topics related to the study of all forms of yoga, from ancient to contemporary, across multiple humanities and social sciences disciplines. Note that JoYS does not accept submissions of natural sciences, medical or experimental psychology articles, but would welcome review or analytical articles written by specialists in these fields with the specific aim of reporting relevant findings to non-specialist academic readers. Authors will retain copyright of their articles.

JoYS aims to serve the needs of this emerging field of study by offering a forum for reporting on research findings, discoveries, theoretical discussions and critical debates in the field, and for disseminating critical editions, translations, book reviews and other key reference materials.

As the ‘study of Yoga’ is a broad and varied subject, the scope of JoYS is inclusive of all forms of rigorous intellectual activity including but not limited to Religious Studies, Modern, Medieval and Classical History of South Asia, Indology, Philology, Philosophy, Anthropology, Sociology, Political Studies, Literature and Arts.

To start with, papers will be published on a rolling-basis throughout the year in electronic form only (downloadable PDF). A yearly collection of papers will form a single volume of JoYS . On occasion, a number of papers may be gathered together under a specific thematic heading (article sets).

The scope of JoYS is limited only by the expertise of its editors and peer-reviewers. Guest editors may be invited to oversee the production of a JoYS article set themed towards a specific topic or subject of interest.

JoYS published its two inaugural articles on 1st May 2018.

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Scientific Research on Yoga

Main research categories.

Substantial research has been done on many of the populations and parts of the body that COVID-19 preys on most. Use this section of Yoga Alliance's website to learn more about scientific research on the effects of yoga on the elderly , respiratory function , anxiety , and depression , to name a few.

Perhaps more than ever, yoga is being widely studied and evaluated for its positive effects and benefits. At Yoga Alliance, we curate the latest and most relevant research on yoga’s applications in health, wellness, and disease. We have filtered it in a digestible manner for our Registered Yoga Schools and Registered Yoga Teachers as well as for the broader yoga community.

This evidence-based research not only reveals the science of yoga, it also explains its therapeutic efficacy when used in conjunction with conventional medicine. Our goal is that this impactful content will be utilized in a way that highlights even more of yoga’s ancient, multi-faceted ability to improve lives.

Our Research Conversation

Our Director of Yoga Research Dr. Sat Bir Singh Khalsa is a renowned yoga research expert and yoga teacher who has committed his professional life to clinical research surrounding yoga’s full spectrum of healing efficacy.

View a collection of brief videos briefly summarizing yoga research on a variety of specific topics, conditions and populations. These are easy to understand for non-scientists and convey many of the scientific principles and rationale in key studies showing yoga’s benefits.

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View upcoming and previous yoga research webinars on a variety of topics hosted by Kim Weeks. Sessions include a brief lecture by Dr. Khalsa summarizing the research and evidence in easy-to-understand language followed by questions and answers from the attendees.

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Research: This Is How Often You Should Practice Yoga To Reap the Body Acceptance Benefits

I f it's already part of your routine, you're probably aware of a few impressive physical benefits of yoga , like loosening tight muscles, opening your joints, strengthening your core, and more. At the end of a yoga session, you also probably feel greater peace (three cheers for that calmer heart rate )—but research also suggests practicing yoga with a certain frequency can yield a body image-enhancing effect.

Dianne Neumark-Sztainer, PhD, MPH , a professor at the University of Minnesota School of Public Health, led a longitudinal study that asked research participants about their yoga practice—as well as the frequency of it. The result was that some reported feeling mental "satisfaction" toward their body image, including when their body shape remained stable.

The Healthy @ Reader's Digest spoke with Dr. Neumark-Sztainer about her research. Turns out, her findings revealed just the start of what a yoga practice can really do to possibly love yourself more.

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30 minutes of yoga each week can make a difference—and here's what matters most

Within her research through Project EAT (a body of research examining weight-related challenges among diverse young people), Dr. Neumark-Sztainer specifically focused on the mental benefits an individual would have with a regular yoga practice. Her discovery: Those who practiced yoga for an average of at least 30 minutes each week saw benefits.

The professor notes that this type of research can be challenging to quantify, but after evaluating over 1,600 participants, she found that a 30-minute weekly practice can mentally make a difference. Plus, "those who practiced more [experienced] more benefits."

Here was the most powerful factor, Dr.  Neumark-Sztainer says: "If you want to see change, it needs to be a regular practice." It's the consistency that seems to catalyze that healthy reset.

Yoga stretches you beyond physical exercise

There are a handful of studies that link practicing yoga and reduced stress levels, but a 2021 study published in Stress Health reported how practicing yoga at least once a week for 12 weeks can make a significant difference.

In the study, participants practiced yoga—which included meditation, breathing exercises, postures, relaxation—for 90 to 115 minutes per session. (Longer times happened earlier in the 12-week study, followed by a half hour of teaching in theory and philosophy.) After, participants reported an improvement in their perceived stress and stress activity.

Separately, NYU School of Medicine  found practicing yoga to be more effective than other methods of managing stress and anxiety.

Yoga improves mental clarity and focus

A typical part of yoga practice, meditation can improve brain health with sharper clarity and focus. A 2019 review in Brain Plasticity reported how a frequent yoga practice slows down age-related and neurodegenerative declines.

Harvard Health notes how magnetic resonance imaging  ( M R I) scans have even shown how a yoga practice creates new neurological activity, even changing brain structure and improving cognitive skills such as learning and memory.

Yoga benefits physical health and quality life

Along with mental benefits, there are a variety of ways frequently practicing yoga has been linked to improved physical health from a myriad of markers. Studies show how yoga practice can enhance muscular strength, flexibility, respiratory and cardiovascular function, sleep, and can even promote recovery from and treatment of addiction.

Yoga increases body image satisfaction

Just showing up to the mat, then moving through a yoga flow, is proof of how much you love yourself, even on days it might feel hard to do so. 

Ready to also reap the benefits of yoga? If you're looking to get started with a yoga practice but need to start small, try any of these: 

• The 5 Best Yoga Poses for a Healthier Gut, from a Registered Yoga Teacher
• 6 Morning Yoga Stretches to Start Your Day
• A Bone Health Doctor Just Listed the 12 Best Yoga Poses to Strengthen Bones

For more wellness updates, subscribe to   The Healthy @ Reader’s Digest   newsletter  and  follow The Healthy on  Facebook  and  Instagram .  Keep reading:

• Here's How Long You Should Hold a Yoga Pose, Says a 50-Year Expert
• 8 Foods You Should Never Eat Before Sex, Say Dietitians
• ‘Am I Smart?’ 8 Scientific Cues That Signal Intelligence, from Neuroscientists
• Here’s Why You’re Hungry After a Nap, Says a Nutrition Expert

The post Research: This Is How Often You Should Practice Yoga To Reap the Body Acceptance Benefits appeared first on The Healthy .

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Why some doctors are prescribing yoga to their patients

Research into adults who practice yoga regularly has found that it can improve sleep, lessen anxiety and depression, and increase mindfulness.

By Sarah Gambles

When Chanel Nelson found out she would need to have back surgery to fix two herniated discs, her neurosurgeon recommended she start building up core strength to help her recover afterward.

To build up that strength, Nelson committed to going to yoga every day for 30 days. At the end of those 30 days, Nelson noticed her back pain had lessened and postponed the surgery. And then she kept postponing the surgery and kept going to yoga.

“It brought me back,” Nelson told the Deseret News. “It was my physical and emotional healing. I like to say yoga saved me from having surgery because I never ended up having surgery.”

Nelson isn’t the only one who has found healing through yoga. While doing yoga might not prevent surgery for everyone, research has found there are many health benefits it can provide if it’s the right fit for you. Some doctors are even prescribing yoga to patients due to its health benefits.

There are now established yoga therapy programs at major health care centers, including The University of Texas MD Anderson Cancer Center and Memorial Sloan Kettering Cancer Center. According to Yoga Journal , there are “more than 500 research papers on yoga therapy (that) have been published in peer-reviewed journals.”

“The practice of yoga is not as easy or as quick as taking medication, but mounting evidence suggests it is worth the effort and investment,” Ina Stephens writes about medical yoga therapy for the journal Children .

Physical health benefits of yoga

Yoga was introduced to the world 5,000 years ago in India, and has been a celebrated practice in the East since. People in the West are slowly starting to be introduced to yoga — more than 14% of Americans practiced yoga in 2017, according to a survey by the Centers for Disease Control and Prevention.

One Harvard study “found that people who practiced yoga for at least 30 minutes once a week for at least four years, gained less weight during middle adulthood.”

A large part of what researchers ascribed to the discovery of weight management in connection with practicing yoga stemmed from not just the physical exercise, but the mindfulness that comes from a yoga practice.

“Both years of yoga practice and number of minutes of practice per week were associated with better mindful eating scores,” the study said. “Practicing yoga helps you be more aware how your body feels.”

Yoga and stress management

That mindfulness can help with other areas of life as well, including managing stress, anxiety and depression. One study found that “yoga is more effective in decreasing anxiety symptoms than aerobic exercise.”

When it comes to managing stress, Dr. Doreen Wiggins, a breast surgeon at Lifespan and the director of the Cancer Survivorship Medicine program, prescribes yoga to her patients to help “empower” patients who are facing cancer treatments.

“Yin Yoga is a great form of yoga because it allows you to hold poses and to perhaps sit with a little bit of discomfort, so it could actually help us foster some resilience because many of us are sitting with discomfort right now,” Wiggins told You Aligned .

Yoga and sleep

One aspect of health that Sat Bir Singh Khalsa, a researcher at Harvard Medical School who wrote the book “Your Brain on Yoga,” touts is how a regular yoga practice can improve sleep.

“Sleep is actually a very sensitive biological function,” Khalsa said during a teleseminar , “Your Brain on Yoga,” for the Alzheimer’s Research & Prevention Foundation. “This is a very sensitive mind-body marker of chronic stress, and it is something that immediately improves when you start to practice yoga.”

One study found that a regular yoga practice helped increase the quality of sleep in adults as well as helped lower symptoms of depression.

Khalsa says that good sleep comes down to a solid ability to deal with stress, which he says yoga can help with.

“Many people will get immediate effects from practicing yoga over the course of a few minutes,” Khalsa said . “As one continues to practice over time, there are structural changes that take place in the brain where people become more resilient to stress and less impaired.”

To get the best results with better sleep? Practice yoga regularly, not just once a month, he says.

Shortly after Nelson discovered her passion for yoga, she became a yoga teacher in addition to working as a surgical tech. She says a lot of the health benefits she finds from her yoga practice stem from just that — a practice of it.

“It’s not about handstands or splits,” Nelson said. “The process to get to those places — we talk about the journey — that’s where we get the benefits. It’s the journey.”

Where to get started with yoga

There are many different styles of yoga taught by a variety of teachers. Do your research first to find out what kind fits best for you and check with your doctor before getting started if you have any health conditions that could affect your experience with yoga.

Here are some of the most popular styles of yoga:

• Vinyasa yoga — a flow of movement coordinated with breath to flow from one movement to another.
• Hatha yoga — yoga that is grounded in a physical practice and is typically a slower pace than vinyasa.
• 26 postures or Bikram yoga — this practice is always done in a hot sauna-like room and follows a sequence of a set 26 postures.
• Yin yoga — a slower-paced version of yoga that focuses on seated postures that are held for longer periods of time.

Many affordable and even free classes are offered online through YouTube or other sites where you can get started. But if you have the ability to attend a class in person, it can be extremely beneficial, especially when it comes to finding community through practice.

Nelson advises exercising patience with yourself when you’re getting started with yoga or if you’re coming back to the practice after a break, and she says she reminds herself that when she first started she couldn’t touch her toes.

“There’s humility in it. Be kind to yourself,” Nelson said.

Shona Kay owns a greenhouse called Greenhouse Wellness in Orem, Utah, where she hosts wellness workshops and free yoga classes led by different instructors, where students can practice yoga and wellness amid plant life. She told the Deseret News that one reason she practices yoga is to get out of her head.

“With most other exercises, there’s competition — how am I doing in terms of this other person or with them?” Kay said. “With yoga, you can close your eyes the entire time and you still get the benefits. It’s just you here. There’s no winning or losing or even arriving.”

She says that the power of yoga for her is its ability to bring her back into alignment with who she is and what she needs.

“When that conversation is open, you’re connected to your intuition, you’re aligned to your purpose to be more of you who you are,” Kay said. “That’s why yoga is such a whole healing. It’s not magic. We aren’t broken, it’s just bringing us back into alignment with who we are.”

Trump lender Axos plunges 15% after short-seller report flags real-estate loan risk

• Axos Financial fell as much as 15% on Tuesday after Hindenburg Research announced a short position.
• The short bet stems from Axos' large exposure to commercial real estate.
• Despite more exposure than its peers, Axos' valuation trades at a premium, Hindenburg said.

Shares of Axos Financial dove as much as 15% on Tuesday after short seller Hindenburg Research announced a bet against the California-based bank.

In a note , the research firm outlined that it's taken a short position in the lender, citing Axos' rising exposure to commercial real estate. Despite brewing uncertainty in the sector, the bank has been building a portfolio around it, the report said.

"Contrary to many peers who backed away from the deteriorating commercial real estate market post-covid pandemic, Axos doubled down, increasing its total exposure from $5.5 billion in March 2021 to $9.9 billion in March 2024," Hindenburg said. "Now, 53% of Axos' total loan book is exposed to these segments."

Between higher interest rates and a declining demand for office properties, analysts are waiting for a loan crisis to eventually swamp the real estate market. With over $2 trillion in debt coming due in the next few years , lenders have been shrinking their exposure to the space — sometimes at a loss .

To compare with Axos, the noted cited that the average direct commercial real estate exposure among regional banks is 16.5% on loan books.

But not only has Axos increased its position, the bank trades at a 35% price to tangible book value premium to its peers, Hindenburg said. That implies outsized growth, a low-risk loan book, and years of upside ahead of it, the note argued.

But instead, Hindenburg's research "indicates a company exposed to the riskiest asset classes with lax underwriting standards and a loan book filled with multiple glaring problems," it said. According to sources who spoke with Hindenburg, issues include a client base of doubtful and non-performing borrowers.

Through a Securities and Exchange Commission  filing  published Tuesday, Axos challenged Hindenburg's report as inaccurate and misleading.

Among criticisms was a failure to mention fund partners backing Axos' credit position, it said, "as well as inaccurate discussions of loans that that have already been repaid but not represented in the report as having been repaid."

CEO Greg Garrabrants also previously told Bloomberg that commercial real estate fears are overdone, and the risk is already reflected by Axos' stock price.

Though not mentioned in the report, among the bank's former borrowers are president Donald Trump. Axos has previously refinanced a $100 million loan on Trump Tower , and lent funds to a Florida resort.

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'Fear-mongering' political rhetoric is driving up hate crimes against Arizona Asians, reports say

As the influx of Chinese migrants across the U.S.-Mexico border rose last year, disinformation depicting them as drug smugglers or spies for the Chinese government circulated among politicians.

Such inflammatory rhetoric has caused harm in Asian communities across the U.S. and locally.

In Arizona, Asian residents experienced more than 100 instances of racial violence during the pandemic, according to Stop AAPI Hate, an organization launched in 2020 to document anti-Asian activity and incidents of hate in the U.S. during the pandemic.

Research indicates that one-third of Asian Americans are still facing anti-Asian problems after the pandemic.

A Democracy Watch poll conducted in March by Asian and Pacific Islander Vote, a nonpartisan organization representing that demographic, studied the problem. The group found that misleading narratives about the huge number of Chinese migrants entering the Southwest border were gaining traction online.

This research argues this increases the perceived threat against many Chinese and Asians in America. The way stories about Chinese migrants are told only intensifies the years of tension.

U.S. Customs and Border Protection data from April indicates that 27,700 migrants with People's Republic of China citizenship were encountered at the Southwest border in the fiscal year that began seven months earlier.

That figure already surpassed the total number of 24,314 Chinese migrants in the entire previous fiscal year, 2023, on the border. Fiscal year 2023 had already seen 10 times the number as the prior 12 months.

In Arizona specifically, 4,155 Chinese encounters were recorded in the fiscal year of 2023, a more than 28-fold increase from 2022, when there were only 147.

Two unproven claims about these immigrants rapidly spread on social media: They are either spies of the Chinese Communist Party or the part of Chinese drug cartels smuggling fentanyl into the U.S. The Democracy Watch report defines this information as “fear-mongering narratives,” used by “prominent right-wing actors.”

The report cited Congresswoman Elise Stefanik posting one such statement on her X account.

“Over 20,000 Communist Chinese nationals have illegally crossed the Southern Border since October, and we know the #CCP has set up sleeper cells in our communities,” she wrote. Her post, updated on March 17, recorded 34,700 views and was reposted 256 times.

U.S. officials repeatedly told U.S. news outlets no link existed between Chinese migrants and criminal activities, the study noted.

The study also recommended how Asians and Pacific Islanders should talk about this issue: "If asked, explain that the increase in Chinese migrants is a result of increasing political crackdowns in the country and economic uncertainty.”

Kyle Van Fleet, the anti-disinformation project manager at APIAVote, emphasized that the majority of the mis- or disinformation detected by APIAVote follows the same structure, which foments distrust in democracy and widens the gap among various communities. This has been particularly intensified in AAPI communities since the pandemic began in 2020.

“Since 2016, we’ve seen increasing anti-China rhetoric, only exacerbated by the pandemic, with the same goal: to fear-monger that the CCP, and by extension Chinese people (as well as Asians and immigrants at large), are somehow behind various societal woes and are threats,” Van Fleet said.

“We aren't aware of any official investigation or confirmation about allegations of Chinese migrants being spies or involved in drug trafficking. However, we are aware that this type of rhetoric and narrative-pushing is an often-used tactic from the playbook to demonize immigrants and communities of color,” he added.

Anti-Asian hate didn't stop with the pandemic

The well-documented inflow of fentanyl from China into the United States is a highly controversial issue between the two countries. On Oct. 3, an investigation by the U.S. Department of Homeland Security led to charges against three chemical companies in China and their workers. They were accused of illegal fentanyl sales.

Starting in 2022, Homeland Security Investigations agents infiltrated Chinese chemical companies that sold narcotics and their precursors online internationally. They discovered that one company shipped over 500 kilos of fentanyl precursors to Tucson via UPS. The fentanyl precursors were not transported by Chinese migrants crossing the U.S.-Mexico border.

The fentanyl scare added ongoing fears and ignorance that cropped up during the COVID-19 pandemic. Asian Americans are still feeling ethnic discrimination from it.

Lawsuit: Black men sue American Airlines, alleging racial discrimination on Phoenix flight

3 in 10 Asian Americans were harassed in past year, study says

The STAATUS Index Report 2024, a study on attitudes toward Asian Americans, Native Hawaiians, and Pacific Islanders, published by the Asian American Foundation, documented it. A total of 6,272 Americans across the country participated in this research.

It highlighted that “Nearly 3 in 10 Asian Americans were verbally harassed or abused in the last 12 months because of their race, ethnicity, or religion.” 

Another finding of the survey was that “41% of Asian Americans think they are likely to be the victim of a physical attack and 59% of Asian Americans think it is at least somewhat likely that they will be a victim of discrimination in the next five years because of their race, ethnicity, or religion.”

Aggie Yellow Horse, an associate professor of Asian Pacific American Studies in the School of Social Transformation at Arizona State University, analyzed data at Stop AAPI Hate.

Moved by the news of an Asian child's attack in a Sam’s Club in Texas in 2020, and having a child of similar age herself, Yellow Horse decided to do something for Asian communities. She was also curious about the developments in Arizona, which was among the states with the fastest-growing Asian populations in the U.S.

From 2020 to 2022, Stop AAPI Hate reported 112 incidents of anti-Asian hate in Arizona.

Most incidents involved verbal harassment, but there were also cases of behavioral harassment, humiliation through written or visual materials, and threats of physical harm.

Yellow Horse pointed out that this data might be the tip of the iceberg due to lack of information among AAPI people about where or how to report these disturbing experiences.

“Stop AAPI Hate is based in California and people might not even be aware of this group in other states. It was hard for some Asian citizens to get help in the situation of discrimination,” she said.

“Fortunately, it seems that there are now fewer people who harshly tell some Asian students at ASU to ‘go back to your country,’ compared to when the coronavirus first became widespread. However, it is difficult to declare that discrimination has vanished simply because it is not visible.”

'Anti-Asian sentiment is deeply rooted in the country'

Educating students about the history and culture of AAPI communities in K-12 schools has been suggested as one solution to prevent ethnic conflicts in the U.S.

California has already taken steps toward this goal. In October 2021, it became the first state to mandate ethnic studies as a high school graduation requirement.

Yellow Horse also believes in collecting and building accurate data on the AAPI community in the U.S. for an extended period. It is systematically gathering detailed reports of hate incidents, demographic statistics, and media coverage related to the AAPI community, so policymakers and community leaders can devise targeted interventions.

“Because the number of Asian people in the United States is still relatively small, their circumstances and solutions to their issues are often overlooked when discussing national policies. Particularly when trying to identify what the problems are, data is frequently requested, but due to the lack of data, these issues are often left out of the conversation,” Yellow Horse said.

The STAATUS Index Report 2024 concluded: “There is no easy solution to addressing these challenges. Anti-Asian sentiment is deeply rooted in the country, spanning beyond today’s political rhetoric and the cloud of COVID-19.”

Seoka Hwang is a reporter for the Busan Daily News in South Korea. He's working with The Arizona Republic while on a  Hubert H. Humphrey Fellowship  at Arizona State University's Walter Cronkite School of Journalism and Mass Communication.

The state of AI in early 2024: Gen AI adoption spikes and starts to generate value

If 2023 was the year the world discovered generative AI (gen AI) , 2024 is the year organizations truly began using—and deriving business value from—this new technology. In the latest McKinsey Global Survey  on AI, 65 percent of respondents report that their organizations are regularly using gen AI, nearly double the percentage from our previous survey just ten months ago. Respondents’ expectations for gen AI’s impact remain as high as they were last year , with three-quarters predicting that gen AI will lead to significant or disruptive change in their industries in the years ahead.

About the authors

This article is a collaborative effort by Alex Singla , Alexander Sukharevsky , Lareina Yee , and Michael Chui , with Bryce Hall , representing views from QuantumBlack, AI by McKinsey, and McKinsey Digital.

Organizations are already seeing material benefits from gen AI use, reporting both cost decreases and revenue jumps in the business units deploying the technology. The survey also provides insights into the kinds of risks presented by gen AI—most notably, inaccuracy—as well as the emerging practices of top performers to mitigate those challenges and capture value.

AI adoption surges

Interest in generative AI has also brightened the spotlight on a broader set of AI capabilities. For the past six years, AI adoption by respondents’ organizations has hovered at about 50 percent. This year, the survey finds that adoption has jumped to 72 percent (Exhibit 1). And the interest is truly global in scope. Our 2023 survey found that AI adoption did not reach 66 percent in any region; however, this year more than two-thirds of respondents in nearly every region say their organizations are using AI. 1 Organizations based in Central and South America are the exception, with 58 percent of respondents working for organizations based in Central and South America reporting AI adoption. Looking by industry, the biggest increase in adoption can be found in professional services. 2 Includes respondents working for organizations focused on human resources, legal services, management consulting, market research, R&D, tax preparation, and training.

Also, responses suggest that companies are now using AI in more parts of the business. Half of respondents say their organizations have adopted AI in two or more business functions, up from less than a third of respondents in 2023 (Exhibit 2).

Gen AI adoption is most common in the functions where it can create the most value

Most respondents now report that their organizations—and they as individuals—are using gen AI. Sixty-five percent of respondents say their organizations are regularly using gen AI in at least one business function, up from one-third last year. The average organization using gen AI is doing so in two functions, most often in marketing and sales and in product and service development—two functions in which previous research  determined that gen AI adoption could generate the most value 3 “ The economic potential of generative AI: The next productivity frontier ,” McKinsey, June 14, 2023. —as well as in IT (Exhibit 3). The biggest increase from 2023 is found in marketing and sales, where reported adoption has more than doubled. Yet across functions, only two use cases, both within marketing and sales, are reported by 15 percent or more of respondents.

Gen AI also is weaving its way into respondents’ personal lives. Compared with 2023, respondents are much more likely to be using gen AI at work and even more likely to be using gen AI both at work and in their personal lives (Exhibit 4). The survey finds upticks in gen AI use across all regions, with the largest increases in Asia–Pacific and Greater China. Respondents at the highest seniority levels, meanwhile, show larger jumps in the use of gen Al tools for work and outside of work compared with their midlevel-management peers. Looking at specific industries, respondents working in energy and materials and in professional services report the largest increase in gen AI use.

Investments in gen AI and analytical AI are beginning to create value

The latest survey also shows how different industries are budgeting for gen AI. Responses suggest that, in many industries, organizations are about equally as likely to be investing more than 5 percent of their digital budgets in gen AI as they are in nongenerative, analytical-AI solutions (Exhibit 5). Yet in most industries, larger shares of respondents report that their organizations spend more than 20 percent on analytical AI than on gen AI. Looking ahead, most respondents—67 percent—expect their organizations to invest more in AI over the next three years.

Where are those investments paying off? For the first time, our latest survey explored the value created by gen AI use by business function. The function in which the largest share of respondents report seeing cost decreases is human resources. Respondents most commonly report meaningful revenue increases (of more than 5 percent) in supply chain and inventory management (Exhibit 6). For analytical AI, respondents most often report seeing cost benefits in service operations—in line with what we found last year —as well as meaningful revenue increases from AI use in marketing and sales.

Inaccuracy: The most recognized and experienced risk of gen AI use

As businesses begin to see the benefits of gen AI, they’re also recognizing the diverse risks associated with the technology. These can range from data management risks such as data privacy, bias, or intellectual property (IP) infringement to model management risks, which tend to focus on inaccurate output or lack of explainability. A third big risk category is security and incorrect use.

Respondents to the latest survey are more likely than they were last year to say their organizations consider inaccuracy and IP infringement to be relevant to their use of gen AI, and about half continue to view cybersecurity as a risk (Exhibit 7).

Conversely, respondents are less likely than they were last year to say their organizations consider workforce and labor displacement to be relevant risks and are not increasing efforts to mitigate them.

In fact, inaccuracy— which can affect use cases across the gen AI value chain , ranging from customer journeys and summarization to coding and creative content—is the only risk that respondents are significantly more likely than last year to say their organizations are actively working to mitigate.

Some organizations have already experienced negative consequences from the use of gen AI, with 44 percent of respondents saying their organizations have experienced at least one consequence (Exhibit 8). Respondents most often report inaccuracy as a risk that has affected their organizations, followed by cybersecurity and explainability.

Our previous research has found that there are several elements of governance that can help in scaling gen AI use responsibly, yet few respondents report having these risk-related practices in place. 4 “ Implementing generative AI with speed and safety ,” McKinsey Quarterly , March 13, 2024. For example, just 18 percent say their organizations have an enterprise-wide council or board with the authority to make decisions involving responsible AI governance, and only one-third say gen AI risk awareness and risk mitigation controls are required skill sets for technical talent.

Bringing gen AI capabilities to bear

The latest survey also sought to understand how, and how quickly, organizations are deploying these new gen AI tools. We have found three archetypes for implementing gen AI solutions : takers use off-the-shelf, publicly available solutions; shapers customize those tools with proprietary data and systems; and makers develop their own foundation models from scratch. 5 “ Technology’s generational moment with generative AI: A CIO and CTO guide ,” McKinsey, July 11, 2023. Across most industries, the survey results suggest that organizations are finding off-the-shelf offerings applicable to their business needs—though many are pursuing opportunities to customize models or even develop their own (Exhibit 9). About half of reported gen AI uses within respondents’ business functions are utilizing off-the-shelf, publicly available models or tools, with little or no customization. Respondents in energy and materials, technology, and media and telecommunications are more likely to report significant customization or tuning of publicly available models or developing their own proprietary models to address specific business needs.

Respondents most often report that their organizations required one to four months from the start of a project to put gen AI into production, though the time it takes varies by business function (Exhibit 10). It also depends upon the approach for acquiring those capabilities. Not surprisingly, reported uses of highly customized or proprietary models are 1.5 times more likely than off-the-shelf, publicly available models to take five months or more to implement.

Gen AI high performers are excelling despite facing challenges

Gen AI is a new technology, and organizations are still early in the journey of pursuing its opportunities and scaling it across functions. So it’s little surprise that only a small subset of respondents (46 out of 876) report that a meaningful share of their organizations’ EBIT can be attributed to their deployment of gen AI. Still, these gen AI leaders are worth examining closely. These, after all, are the early movers, who already attribute more than 10 percent of their organizations’ EBIT to their use of gen AI. Forty-two percent of these high performers say more than 20 percent of their EBIT is attributable to their use of nongenerative, analytical AI, and they span industries and regions—though most are at organizations with less than $1 billion in annual revenue. The AI-related practices at these organizations can offer guidance to those looking to create value from gen AI adoption at their own organizations.

To start, gen AI high performers are using gen AI in more business functions—an average of three functions, while others average two. They, like other organizations, are most likely to use gen AI in marketing and sales and product or service development, but they’re much more likely than others to use gen AI solutions in risk, legal, and compliance; in strategy and corporate finance; and in supply chain and inventory management. They’re more than three times as likely as others to be using gen AI in activities ranging from processing of accounting documents and risk assessment to R&D testing and pricing and promotions. While, overall, about half of reported gen AI applications within business functions are utilizing publicly available models or tools, gen AI high performers are less likely to use those off-the-shelf options than to either implement significantly customized versions of those tools or to develop their own proprietary foundation models.

What else are these high performers doing differently? For one thing, they are paying more attention to gen-AI-related risks. Perhaps because they are further along on their journeys, they are more likely than others to say their organizations have experienced every negative consequence from gen AI we asked about, from cybersecurity and personal privacy to explainability and IP infringement. Given that, they are more likely than others to report that their organizations consider those risks, as well as regulatory compliance, environmental impacts, and political stability, to be relevant to their gen AI use, and they say they take steps to mitigate more risks than others do.

Gen AI high performers are also much more likely to say their organizations follow a set of risk-related best practices (Exhibit 11). For example, they are nearly twice as likely as others to involve the legal function and embed risk reviews early on in the development of gen AI solutions—that is, to “ shift left .” They’re also much more likely than others to employ a wide range of other best practices, from strategy-related practices to those related to scaling.

In addition to experiencing the risks of gen AI adoption, high performers have encountered other challenges that can serve as warnings to others (Exhibit 12). Seventy percent say they have experienced difficulties with data, including defining processes for data governance, developing the ability to quickly integrate data into AI models, and an insufficient amount of training data, highlighting the essential role that data play in capturing value. High performers are also more likely than others to report experiencing challenges with their operating models, such as implementing agile ways of working and effective sprint performance management.

About the research

The online survey was in the field from February 22 to March 5, 2024, and garnered responses from 1,363 participants representing the full range of regions, industries, company sizes, functional specialties, and tenures. Of those respondents, 981 said their organizations had adopted AI in at least one business function, and 878 said their organizations were regularly using gen AI in at least one function. To adjust for differences in response rates, the data are weighted by the contribution of each respondent’s nation to global GDP.

Alex Singla and Alexander Sukharevsky  are global coleaders of QuantumBlack, AI by McKinsey, and senior partners in McKinsey’s Chicago and London offices, respectively; Lareina Yee  is a senior partner in the Bay Area office, where Michael Chui , a McKinsey Global Institute partner, is a partner; and Bryce Hall  is an associate partner in the Washington, DC, office.

They wish to thank Kaitlin Noe, Larry Kanter, Mallika Jhamb, and Shinjini Srivastava for their contributions to this work.

This article was edited by Heather Hanselman, a senior editor in McKinsey’s Atlanta office.

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3rd June – Threat Intelligence Report

For the latest discoveries in cyber research for the week of 3rd June, please download our Threat_Intelligence Bulletin .

TOP ATTACKS AND BREACHES

• ShinyHunters, a notorious cybercrime gang offered for sale on a cybercrime forum data of Ticketmaster, ticket sales and distribution company, and of Santander bank. The alleged breaches have resulted in the potential exposure of personal data belonging to millions of customers. Some assumption claim that actor gained access to Ticketmaster and Santander by using the stolen credentials of a single employee of Snowflake, a large cloud storage company.
• Researchers have uncovered a malware attack where over 600,000 SOHO routers were taken offline across a single ISP’s network, resulting in hardware-based replacement of the affected devices. The analysis revealed that the attack was conducted with the Chalubo RAT, and featured advanced obfuscation techniques and was aimed at permanent hardware disablement. This incident significantly disrupted services in smaller towns and less developed areas.
• Japanese crypto exchange DMM Bitcoin confirmed a data breach that resulted in the loss of 4,502.9 BTC ($308 million). The incident is said to be one of the largest crypto heists and involves funds being moved to multiple wallets. Investigations are ongoing to track the stolen assets and notify affected parties.
• Sav-Rx, a U.S. based prescription management company, recently disclosed a significant data breach affecting over 2.8 million Americans. This incident, which occurred in 2023, involved the theft of personal data from Sav-Rx’s systems. The company has confirmed that sensitive personal information was compromised but assured that no payment information was included in the breached data​.
• Christie’s, the world’s largest auction house, has been breached by the RansomHub ransomware group. The attack has potentially exposed sensitive information of 500,000 of Christie’s clients and led to a shutdown of the website right before its spring sales in New York began.

Check Point Threat Emulation provides protection against this threat (Trojan.Wins.Imphash.taim.JI, Trojan.Wins.Imphash.taim.HQ)

• The Seattle Public Library experienced a ransomware attack that has disabled its digital services, including the wireless network, staff and patron computers, and online catalog. The library’s 27 branches continue to operate manually for book and CD lending.
• The BBC Pension Fund has reported a breach, where unauthorized access was gained to steal personal information of the enrolled staff. The breach was conducted by cybercriminals aiming to exploit sensitive member data for fraudulent purposes.

VULNERABILITIES AND PATCHES

• Check Point has issued a warning about a high score zero-day vulnerability (CVE-2024-24919) exploited In the Wild, affecting its Security Gateways with IPsec VPN in Remote Access VPN community and the Mobile Access software blade. Exploitation of this vulnerability could allow threat actors to access certain information on internet-connected Gateways with remote access VPN or mobile access enabled.

Check Point IPS provides protection against this threat (Check Point VPN Information Disclosure (CVE-2024-24919))

• TP-Link has patched a critical vulnerability (CVE-2024-5035) in the C5400X gaming router, which allows remote code execution. The vulnerability stemmed from improper handling of input in the ‘rftest’ binary accessible via network service ports.

THREAT INTELLIGENCE REPORTS

• Check Point Research has examined a group of malicious packers based on the Nullsoft Scriptable Install System (NSIS), uncovering mechanisms for evading detection and delivering malware payloads. In this technical analysis, CPR highlights the packer’s flexibility and persistent threat in cyber environments, identifying multiple malware types such as loaders, stealers, and Remote Access Trojans.

Check Point Threat Emulation provides protection against this threat (Packer.Win.NSISCrypter.*, Trojan.Win.Shellcode.F, Trojan.Win.Shellcode.G)

• Europol, in coordination with international law enforcement agencies, conducted a disruptive operation against botnets, dubbed Operation Endgame, targeting the dropper malware ecosystem. Notably, the operation disrupted the infrastructure of 100 malware servers including of Trickbot, IcedID, SystemBC, Pikabot, Smokeloader and Bumblebee, alongside the arrest of key individuals involved in distributing dropper malware. Reportedly, many of interrupted malware are regularly used by multiple ransomware groups, including BlackBasta, Revil and Conti.
• Researchers have shared information on the obfuscation tactics of Water Sigbin (8220 Gang), a China-linked threat actor deploying cryptocurrency mining malware. The group exploited Oracle WebLogic vulnerabilities (CVE-2017-3506 and CVE-2023-21839) using PowerShell scripts and sophisticated encoding methods, including hexadecimal encoding of URLs and fileless execution via .NET reflection techniques in PowerShell scripts.

Check Point IPS provides protection against this threat (Oracle WebLogic WLS Security Component Remote Code Execution (CVE-2017-10271), Oracle WebLogic Server Improper Access Control (CVE-2023-21839))

• Researchers observed an escalation in attacks targeting operational technology (OT) devices, particularly those with poor security and internet exposure. These attacks, notably by nation-backed groups like the IRGC-affiliated CyberAv3ngers, demonstrate the vulnerability of OT systems across various sectors.

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• Israeli Views of the Israel-Hamas War

Jewish Israelis and Arab Israelis see the war very differently

Table of contents.

• Views of the Israeli military response against Hamas
• Attitudes toward Israel’s war cabinet
• Current concerns about the war
• Confidence in Biden
• Views of how Biden is handling the Israel-Hamas war
• Who is Biden favoring in the conflict, or is he striking the right balance?
• Views of the U.S.
• Who Israelis want to play a role in diplomatically resolving the war
• Success against Hamas
• Israel’s future national security
• The future of Gaza
• Views of Palestinian leaders
• Palestinian statehood and coexistence
• Acknowledgments
• Methodology

This Pew Research Center analysis covers Israeli attitudes on the Israel-Hamas war, including opinions on how it’s being conducted, the country’s future, Israeli political leaders and the United States’ role in the conflict.

The data is from a survey of 1,001 Israeli adults conducted face-to-face from March 3 to April 4, 2024. Interviews were conducted in Hebrew and Arabic, and the survey is representative of the adult population ages 18 and older, excluding those in East Jerusalem and non-sanctioned outposts. (The survey also did not cover the West Bank or Gaza.) The survey included an oversample of Arabs in Israel. It was subsequently weighted to be representative of the Israeli adult population with the following variables: gender by ethnicity, age by ethnicity, education, region, urbanicity and probability of selection of respondent.

Here are the questions used for the report, along with responses, and the survey methodology .

A new Pew Research Center survey finds that 39% of Israelis say Israel’s military response against Hamas in Gaza has been about right, while 34% say it has not gone far enough and 19% think it has gone too far.

According to the survey, conducted in March and early April, roughly two-thirds of Israelis are also confident that Israel will either probably (27%) or definitely (40%) achieve its goals in the war against Hamas. Still, majorities of Israeli adults are worried about aspects of the ongoing war: 

• 61% say they are extremely or very concerned about the war expanding into other countries in the region.
• 68% say they are extremely or very concerned about the war going on for a long time.

When it comes to what should happen after the war, there is less consensus. A 40% plurality of Israelis think Israel should govern the Gaza Strip. Smaller shares think Gazans should decide who governs (14%) or would like to see a Palestinian Authority national unity government either with (6%) or without (12%) President Mahmoud Abbas (also known as Abu Mazen) in leadership.

Separately, 26% of Israelis think a way can be found for Israel and an independent Palestinian state to coexist peacefully with each other – down from  35% who said the same last year , prior to the war, and about half as many as took that position when the question was first asked in 2013.

Research in the West Bank and Gaza

Pew Research Center has polled the Palestinian territories in previous years, but we were unable to conduct fieldwork in Gaza or the West Bank for our March/April 2024 survey due to security concerns. We are actively investigating possibilities for both qualitative and quantitative research on public opinion in the region and hope to be able to provide more data in the coming months.

These are among the key findings of a new survey of 1,001 Israelis, conducted via face-to-face interviews from March 3 to April 4, 2024.

The survey also asked Israelis about the U.S. role in the conflict. (It was conducted before U.S. President Joe Biden took a tougher stance toward Israel in the wake of an Israeli airstrike that killed seven World Central Kitchen aid workers. And it predates Biden’s declaration that the U.S. would not provide offensive weapons to Israel in the event of a Rafah invasion as well as the subsequent Israeli strikes in Rafah .)

The survey shows:

• 60% of Israelis disapprove of the way Biden is handling the Israel-Hamas war.
• 41% think Biden is striking the right balance between Israelis and Palestinians. Still, 27% of Israelis say he is favoring Israelis too much, while roughly the same share (25%) say he favors Palestinians too much.
• Most Israelis express confidence in Biden to handle world affairs and have a favorable view of the U.S. But ratings of both Biden and the U.S. have fallen at least 10 percentage points since last year. (For more on this, read “How Israelis and Americans view one another and the U.S. role in the Israel-Hamas war.” )

Nonetheless, a large majority (72%) still want the U.S. to play a major role in diplomatically resolving the war – more than say the same about any of the other countries or organizations asked about, including Egypt (45%), Saudi Arabia (29%), Qatar (27%) and the United Nations (24%).

Arab and Jewish Israelis

People across Israeli society perceive the war in vastly different ways, depending on their views of the current leadership, how they identify ideologically, their religious backgrounds and other factors. One of the starkest divides is between Arab and Jewish Israelis:

• Arab Israelis are less likely than Jewish Israelis to think Israel will succeed in achieving its war aims (38% vs. 76%) and less optimistic when thinking about the future of the country’s national security (21% vs. 63%).
• Israeli Arabs are much more likely than Jews to say the country’s military response has gone too far (74% vs. 4%).
• Almost no Israeli Arabs (3%) want Israel to govern the Gaza Strip after the war, while half of Israeli Jews think it should do so. A plurality of Arabs would like the people who live in Gaza to decide who governs (37%), while only 8% of Jews prefer this outcome.
• Arab Israelis have much less favorable views of the U.S. than Jewish Israelis do (29% vs. 90%), as well as less confidence in Biden (21% vs. 66%). They are also much more likely to disapprove of Biden’s handling of the war (86% vs. 53%) and to think he favors Israelis too much (86% vs. 11%).
• Although a majority of Arabs (63%) want the U.S. to play a major role in diplomatically resolving the war between Israel and Hamas, an even greater share of Jewish Israelis (74%) want this. And roughly two-thirds of Arabs are open to Qatar and Egypt playing a major role, while only about four-in-ten Jews or fewer say the same.
• Roughly nine-in-ten Arabs (92%) have a negative view of Israeli Prime Minister Benjamin Netanyahu, compared with around half of Jews (48%). Views of the two other war cabinet members , Benny Gantz and Yoav Gallant, are also divided along ethnic lines. (The survey was conducted before Gantz threatened to leave the war cabinet .)

In many cases, there are also large ideological differences, with Israelis who describe themselves as being on the left generally more critical of Israel’s war response, less optimistic about its success and more critical of the U.S. than those on the right. There also tend to be differences among Israeli Jews based on how religiously observant they are. For more on how we looked at these differences, refer to the box below.

Jewish religious groups in Israel: Haredim, Datiim, Masortim and Hilonim

Nearly all Israeli Jews identify as either Haredi (commonly translated as “ultra-Orthodox”), Dati (“religious”), Masorti (“traditional”) or Hiloni (“secular”). The spectrum of religious observance in Israel – on which Haredim are generally the most religious and Hilonim the least – does not always line up perfectly with Israel’s political spectrum. On some issues, including those pertaining to religion in public life, there is a clear overlap: Haredim are furthest to the right, and Hilonim are furthest to the left, with Datiim and Masortim in between. But on other political issues, including those related to the Israeli-Palestinian conflict and views of the United States, differences between religious groups do not always mirror those between people at different points on the ideological spectrum. Because of sample size considerations, we combine Haredim and Datiim for analysis in this report.

For more information on the different views of these religious groups, read the Center’s 2016 deep dive on the topic, “Israel’s Religiously Divided Society.”

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a Department of Psychiatry, All India Institute of Medical Sciences, Bhopal, 462020, India

Anju Dhawan

b National Drug Dependence Treatment Centre (NDDTC) & Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, 110029, India

Associated Data

Yoga and meditation-based interventions have been extensively utilized in the field of contemporary complementary and alternative medicine for various physical and mental health conditions. Ongoing COVID-19 pandemic has rekindled the interest of researchers in yoga and meditation for its preventive and therapeutic utilities. However, the available literature in this area has several methodological concerns, limiting formers’ clinical utility. A comprehensive literature on this topic would stimulate researchers and guide them to conduct research on this topic with robust methodologies. The current review highlights the methodological issues with the yoga and meditation-based Research (henceforth, MBR), discusses some of the contentious issues, and provides future directions. The PubMed, Medline, and google scholar databases were searched to screen records dealing with the methodological issues on MBR. The search yielded 299 records, upon screening, only 24 articles were found suitable for the current study. Common methodological issues with MBR: lack of the consensus definitions of the yoga and meditations, interventions lacking theoretical framework of meditation; inadequate description of the study design; difficulty with participants recruitment, setting up the control groups, and blinding; difficulty in assessing the baseline characteristics of the participants, and validity issues with the outcome measures. A few research, however, have also highlighted the potential measures to overcome these methodological challenges. Yoga and meditation-based interventions are promising for several health conditions. However, literature suffers from considerable methodological issues, thus, limiting its utility in modern clinical practice. The study findings can stimulate and guide future research on this topic.

1. Introduction

Meditation and yoga (defined as a combination of meditation and its context) [ 1 ], have gained popularity in contemporary scientific research and have been used for several mental health (stress, anxiety, depressive disorders, etc.) [ 2 , 3 ] and physical conditions (pain, etc.) [ 4 , 5 ]. Worldwide, yoga and meditation are explored as an alternative and complementary approach to the treatment for both psychological and physical disorders, and to attain a better quality of life [ [6] , [7] , [8] , [9] ]. Apart from the clinical population, it has also gained popularity among the non-clinical population as a means to attain a state of general wellbeing. It is seen as a relatively safe, inexpensive, and sustainable measure that can be used as a standalone or as an adjunct to the standard treatment, in achieving good health or for a specific health condition [ 10 , 11 ]. Ongoing COVID-19 pandemic has rekindled the interest of researchers on yoga and meditation for its preventive and therapeutic utilities. Both yoga and meditation (meditation, henceforth) have been utilized for various mental health problems and to boost immunity to fight against the physical impact of the SARS-CoV-2 (COVID-19) infection [ 12 , 13 ].

However, the available research on the yoga and meditation-based interventions suffered from several methodological limitations: non-incorporation of the theoretical framework of the yoga/meditation practices while developing the interventions, lack of validated instruments to measure the practitioners’ experience, issue related to participant recruitment, and setting up effective control arm, concern over monitoring of meditation-based clinical trials, difficulty in assessing the role of various overt and covert factors on the outcome, etc. [ [14] , [15] , [16] , [17] , [18] ]. This has also been reflected in the ongoing research on the efficacy of yoga and meditation-based intervention for mental and physical consequences of COVID19 pandemic [ 19 ].

Despite literature highlighting several methodological issues with yoga and meditation-based Research (henceforth, MBR), available literature is largely restricted to mindfulness meditation, while literature concerning other common forms of yoga and meditation practices is elusive, which have distinct methodological concerns. Furthermore, a comprehensive account on the ontological aspects of the yoga and meditation practices and their adaptation in the modern contemplative neurosciences, and associated challenges, particularly those centering around the meditation-based intervention, is still lacking. An inclusive literature on this topic can stimulate researchers and guide them to conduct research on this area with robust methodologies, which this paper intends to provide.

Hence, the current review is aimed to highlight various methodological issues in conducting research based on meditation-based interventions, discuss some of the contentious issues, and provides future directions.

2.1. PubMed, Medline, and Google Scholar databases were searched with the search terms

‘Yoga’ OR “meditation” (for yoga and meditation), ‘research’ and ‘methodologic issues’ or ‘research implications’ (for methodological concerns) were used to identify the relevant records ( Supplementary file 1 ). The inclusion criteria for the studies to be considered for the current review were articles primarily dealing with the methodological issues on MBR or research implications of these limitations (e.g., issues with the definition, study design, participants recruitment, intervention delivery, outcome assessment, statistical analysis, etc.), irrespective of the type of yoga and meditation practices, from the inception till 14th May 2020. However, articles not directly dealing with the methodological issues, those papers whose full text was not available (despite making efforts to contact the authors), and those not in the English language were excluded. Additional relevant records were obtained through the bibliographic search.

A total of 299 records were obtained. Upon title and abstract screening, only 24 records were found suitable for the current review. Among the 24 articles selected for the review, most were related to methodological issues in researching MM followed by those with transcendental meditation and yoga-based therapies (described in Table 1 ).

Table 1

Summary of the relevant research/papers on the methodological issues with the yoga and meditation.

AT: autonomic transcendence, a/w: associated with, CVDs: cardiovascular disease, d/t: due to, EEG: electroencephalogram, FA: focused attention, HCPs: Healthcare providers, MBR: mindfulness-based research, med.: medium, MEQ30: Revised Mystical Experience Questionnaire, MM: mindfulness meditation, MBI: mindfulness-based interventions, OM: open monitoring, PTSD: post-traumatic stress disorders, RCTs: randomized controlled trials, S/E: side-effects, TM: transcendental Meditation Tt: treatment.

4. Major methodological issues with the available MBR

Literature suggests the common methodological issues with MBR to be lack of the consensus definitions of the meditations, meditation-based interventions lacking theoretical framework of meditation; inadequate description of the study design; difficulty with participants recruitment, setting up the control groups, and blinding; difficulty in assessing the baseline characteristics of the participants, and validity issues with the outcome measures.

4.1. Defining meditation

One of the major methodological issues with MBR is the operational definition of the meditation practice under consideration and to explicitly describe its core component(s). There have been substantial variations in the definition/framework used across the studies, despite a large number of studies on meditation, including the MM, they lack an operational definition and that varies across the studies, as a result, the effect size of the intervention of a particular kind cannot be measured. Meditation has been classified under two broad categories: 1) Focussed attention (FA) (concentrative type), where the practitioner voluntarily focuses ones' attention within oneself (breathe, thoughts, imagery, etc.) or outside (candlewick, an image of the deity, etc.) to the exclusion of all other experiences e.g. Zen meditation, hath yoga, and Sudarshan kriya yoga (SKY) and 2) Open monitoring (OM), where the attention is not directed to a particular thing, but to remain aware in a non-reactive manner about whatever arises in the mental continuum of oneself e.g. MM, Vipassana meditation, etc. [ 20 ] However, this dual classification is limited because of considerable overlaps between the practices, resulting in ambiguity and inconsistencies in the definitions in the literature. Furthermore, a third category of meditation the automatic self-transcendence (AST)-which involves transcending the practice of meditation and harnessing the natural tendency of the body to attain pure consciousness (transcendental meditation [TM], Sahaj Samadhi Meditation)-has also been proposed. It is a state of complete letting go and settling into oneself [ 21 ]. Although AST-based meditations begin with the FA, the very practice of transcending the subject-object duality is effortless from the beginning itself as compared to FA-based meditations. For instance, in TM, the mantra chanting though begins with the FA, the practitioner from the very beginning learns to allow oneself to lose focus from the mantra and transcend the subject-object duality to attain self-awareness [ 22 ]. In fact, of the eight limbs of Yoga described by the ancient sage Maharishi Patanjali, one limb is Pratyahara or focussing inside e.g. focussing attention on the heart region, followed by Dhyana or meditation where thoughts/feelings/body sensations are observed and one is in a state of ‘witness consciousness’ followed by transcendence which is a deeper state where one has completely let go [ 21 , 23 ]. Yet, there is another proposed category, the guided-meditation (GM) (e.g. Love and kindnesses meditation), where the content of meditation takes precedence over other aspects of the meditation, and a practitioner is guided through a set of images, or chants to engage in a particular aspect of self (empathy, kindness, etc.) mindfully [ 24 ].

4.2. Characteristics and components of the yoga and meditation

The available research on yoga and meditation-based interventions has been criticized for not accounting for and not explicitly describing various components of the meditation under study including their key elements [ 2 , 25 ]. Likewise, these baseline differences among the participants of different interventions group can confound the research findings. Therefore, simply focussing on a particular aspect of meditation (like the degree of mindfulness achieved during the MM or level of physical exertion in the hath yoga or Qigong) and excluding other components (the practice of mindfulness in day-to-day activities including exercise, or routine work, etc.) could lead to inaccurate and inconsistent study findings [ 17 ].

Likewise, randomly dismantling the process of the meditative practice (e.g. eliminating the integral moral, or lifestyle changes associated with a particular mediation) as per convenience while developing an intervention, without considering its ontological significance, would lead to the development of a distorted or flawed intervention; the findings of such interventions would not be representative of the original contextual meditation. Consequently, the findings would be inconsistent and less-interpretable [ 14 , 26 ].

4.3. The theoretical framework of yoga and meditation

Yoga and meditations have been practiced since antiquity across different cultures. For instance, the concept of meditation in Hinduism is a practice that helps in attaining the pure-consciousness ( enlightenment or self-connection ) [ 27 ] while Buddhism considers it away to achieve emptiness ( Shunyata, skill to disentangle oneself from the defilement and dissatisfactions; state of no-attachment ) [ 28 ]. Neither of them has developed meditation merely for prevention or treatment of a particular health condition. The researchers involved in contemplative sciences have argued that simply adapting the traditional meditative practices for developing an intervention to treat a particular health condition raises validity concerns. For instance, there are now several MM-based interventions (incorporating the principles of mindfulness to varying degrees) such as mindfulness-based cognitive behavioral therapy (MB-CBT), dialectic behavioral therapy (DBT), acceptance and commitment therapy (ACT), etc. However, research analyzing the construct validity of these interventions is still lacking; similarly, the outcomes and their measures used to assess the effectiveness of these interventions also have validity concerns [ 17 , 25 ]. Such contextual issues act as a prominent hindrance in the field of the MBR. Although picking up these practices without the associated philosophical framework has increased its acceptability in the west and the medical and scientific community worldwide, however, researchers need to be mindful about the fact that such derivations, viewed only microscopically through the lens of modern science, could lead to concern over the time-tested practices that have benefitted people for time immemorial. Be that as it may, the current approach can be pursued for serving the purpose of research and science but with a clear understanding of its limitations.

4.4. Study design

Most of the studies were commentaries or perspectives of the experts followed by the review papers, including systematic review and metanalysis. In addition, one of the studies has supplemented its review paper with the findings of the cross-sectional online survey [ 56 ]. The nature of the current review, and methodological issues with the yoga and meditation-based research, however, restricted the incorporation of the original articles.

4.5. Sample size of the studies

Researchers have also suggested that MBR, especially those on MBI, suffers from the limited sample size of the participants across the comparison groups [ 26 , 29 ]. Moreover, baseline differences between the comparison groups, which often remain unaccounted, could act as confounders in assessing the effectiveness of the meditation-based interventions [ 16 , 26 ].

4.6. Assessment of the effect of the yoga/meditation as a state versus a trait phenomenon or an interaction between them

The existing evidence on the effectiveness of the meditation-based interventions has been criticized for studying and reporting the effect of the meditation only during the meditative state (a state phenomenon) i.e. trying to assess its impact merely based on the neuro-psychological findings during the practice of meditation or by comparing the mental state immediately before and after practice [ 14 , 26 ].

The impact of the meditations is also influenced by the duration of the practice (adept practitioner versus novice), both formal and informal, and the constellation of pre-existing traits of the practitioner (their level of motivation, baseline understanding and expectancies from the meditation, adherence to the practice, and the preparatory steps including the lifestyle modifications associated with the practice) [ 20 , 30 , 31 ]. For instance, in Buddhism, certain prerequisites are there before enrolling an individual into the MM which includes ones' life's goals and the baseline understanding about the Buddhist philosophy; such features determine at which level of meditation the participants to be enrolled in [ 32 ]. In contrast, simply studying the state effect of meditation without considering its long-term effect (trait effect) would limit its clinical utility in the real-world scenario. Thus, it would be prudent to study meditatation in the context of a state and trait interaction.

4.7. Participant recruitment process

Literature suggests that MBR often suffers from selection bias [ 26 ]. Research shows that most of the participants getting involved in the MBR have an inherently higher level of enthusiasm and expectancies towards the meditation than their less enthusiastic counterparts who either do not participate or exhibit lesser compliance with the instructions. Moreover, it is not uncommon for the participants to have a prior association with a particular meditation group, this may be a potential source of bias [ 33 , 34 ]. Lastly, participants’ association with the investigator, if both are part of the same yoga/meditation group, may also lead to a personal relationship effect [ 16 ]. Such samples are not representative of the population from which they are drawn and can also act as a major confounder, therefore, the results of such research have serious generalizability issues and a possibility of biased results (unduly higher effect size of the interventions) could not be ruled out [ 35 ].

4.8. Participant safety

The MBR has been criticized for not adequately accounting for and describing the potential adverse consequences of the meditation especially in the vulnerable population (those with pre-existing physical or mental illnesses) [ 26 ]. Further, MBR has been criticized for not providing adequate information to the participants while obtaining consent. This issue is particularly important as a certain vulnerable population are at risk of experiencing adverse effects which include psychological (depersonalization, psychosis, dysphoria, initial worsening of the anxiety symptoms, etc.), physical (worsening of the somatic symptoms and risk of epilepsy, et.), and spiritual-adverse effects (conflict between the philosophy behind the given meditation and the religious belief of a participant, etc.) [ 36 , 37 ]. This methodological limitation is to a certain extent has to do with the poor knowledge of investigators about the potential meditation-related adverse consequences [ 17 ].

4.9. Randomization, allocation concealment, and blinding

The randomization of the participants adds to the vigor of the study. However, the literature shows that MBR often inadequately describes the process of randomization of the participants. Another methodological limitation is the participants' selection for the study. For instance, if a given intervention is expected to affect the cognitive ability (e.g. multitasking) of the participants, then it is prudent to recruit participants for whom multitasking forms an important part of their work or life [ 18 , 38 ]. This criticism, however, stems from the belief that meditation may affect a specific cognitive ability. However, based on the neurobiological findings that show involvement of multiple areas of the brain during meditation, it is unlikely that the benefits of meditation are so specifically limited to a specific cognitive ability as would happen during a psychological intervention designed to enhance a specific cognitive skill.

The greater issue is related to allocation concealment and blinding. Lack of allocation concealment can introduce a bias in assigning participants to a particular group. This can stem from the association between the participants and the investigators and a potential tendency towards allocating the more enthusiastic participants to the active group than their less interested counterparts. Usually, the MBR follows a wait-list control design or control arm receiving the non-specific interventions like general exercise, dietary advice, self-help books, etc.; consequently, the participants are liable to exhibit demand characteristics (behaving or experiencing in a manner that is expected of their placement in a particular group) [ 26 , 39 ]. Such a bias can also occur at the level of the instructor who may have an association with the meditation group or is aware of which arm they are training to, consequently, their level of effort and commitment may vary accordingly [ 26 ], though this potential bias needs further exploration.

Similarly, the findings of the effectiveness studies are vulnerable to getting biased if the participants, the assessor, or the analyzer/statistician are aware of the group to which a particular participant belongs. Thus, for MBR, blinding at multiple levels (at the level of the participant, assessor, and analyzer) becomes essential.

4.10. Fidelity in delivering the meditation-based interventions

For MBR to progress, it becomes vital that the intervention is delivered in a way it was traditionally intended to. For this to happen, the instructor must have adequate knowledge and experience (including the theoretical framework of meditation) about meditation and its delivery [ 40 ]. However, it has often been argued that researchers often do not provide an adequate description of the characteristics of the instructor (experience, certification, etc.), and the method adopted by them to ensure the fidelity of intervention delivery. These raise concerns about the methodological robustness of the research and also act as a roadblock in replicating the research findings [ 18 , 26 ].

4.11. Outcomes of the yoga and MBR

Although researchers have shown keen interest in studying the positive effects of yoga and meditation as alternative and complementary medicine for various psychological or physical health issues and have tried to develop various interventions based on them, the outcome measures used are still in its infancy and lack validations [ 41 , 42 ]. Without understanding the ontological context of yoga/meditation and the set goals with which it was practiced, which is quite fluid (enlightenment, self-actualization, or to attain pure-consciousness), the outcomes assessed with a reductionist approach (e.g., present-moment-awareness erroneously considered to be a reflection of the psychological construct of the traditional Buddhist concept of mindfulness or any meditation) could act as a major methodological limitation in the ongoing research on meditation [ 43 ]. One major observation is that a large part of the meditation research emanates from the West rather than from the eastern part of the world from where these practices originated and where there is an inherent better understanding of its philosophy and the context. The meditation research seems to have picked up only a minuscule part of the innumerable practices available in eastern culture for research.

4.12. Assessment measures

One of the major methodological issues with MBR is to accurately measure the subjective experiences (mindfulness, relaxation, attaining consciousness, etc.) of the practitioners with any self-report or objective measure [ 14 , 17 , 26 ]. Further, the outcome measures often being used in the research are unspecific, hence cannot delineate the effects of various subtypes of meditative practices and their variations and differentiate the effect of one practice from another. Probably, the reason for this may be that the researcher may expect that the outcomes of such variations among the meditations would differ qualitatively, but not quantitatively. However, this may not be true. For instance, the Sahaj Samadhi Dhyana Yoga is specifically expected to provide relief from past traumatic memories and so, may be studied for its potential benefit in Post-Traumatic Stress Disorders [ 44 ]. Further, relying on the third persons' account for the first-persons’ experience is vulnerable to depict a distorted picture unless the former has a deep knowledge and experience in recognizing and differentiating the various subjective meditative experiences and their outward manifestations [ 41 ]. Similarly, the objective measures (neuro-psychological or electrophysiological findings) used to infer the subjective experience may not accurately capture the real change brought about by the meditation. For instance, it is challenging to accurately and reliably tap the mind wandering, or non-judgemental approaches towards ones' thoughts or other mental states with the help of neuro-imaging. Overenthusiastic and undue attempts to quantify or measure the psychological state of an individual (e.g. mindfulness, non-judgemental, awareness, mind in the present moment) through reverse-inference (a neuro-cognitive sciences' approach in which based on the functional neuroimaging findings [brain activation] the mental state of an individual is inferred) is liable to suffer from biases, a common pitfall in neuro-imaging based study, especially when the pieces of evidence are still evolving [ 45 ]. The construct validity of the measuring instruments has also been debated especially in the absence of any gold-standard reference instrument [ 14 ]. Further, the self-report questionnaires are also likely to get biased depending on the participants' expectancies and prior experience with any meditation (e.g. an experienced practitioner may be better able to delineate and describe ones’ meditative experience as compared to a novice) [ 16 ]. Thus, first-person qualitative research needs to be used more often in meditation research, especially for hypothesis generation.

4.13. Effect of yoga and meditation and sustainability of their benefits

As has been discussed, the effect of the meditation is also determined by several associated factors (such as preparatory measures and lifestyle modifications) [ 14 , 32 ]. Similarly, there are several latent factors such as duration of the informal practice of the meditation (e.g. being mindfulness), ones' personality traits, or expertise in the meditation, etc., and their interrelation, which may influence the overall effect of the meditation on the practitioners [ 17 ]. Moreover, an experienced practitioner of the meditation is vulnerable to exhibit the ‘Hawthorne effect’ (a tendency to perform better or report in an exaggerated positive manner about the effect of the meditation one has been involved in) [ 16 ]. Many studies do not account for, or at least adequately describe these latent variables, thus their results should be interpreted with some caution [ 17 ]. Some of these latent variables may be quite difficult to assess, such as depth of meditation and level of expertise over it, while others such as personality traits may be more easily measurable.

Further, in the absence of long-term follow-up studies assessing the effects of meditation on the practitioner, its sustainable effects are yet to be established. Factors like duration, quality of meditation, compliance with the recommended practice, and practice of more than one type of meditation during the same period are difficult to be ascertained, hence, could act as a hurdle in conducting longitudinal studies on meditation. Moreover, self-report measures are often subjected to recall bias.

4.14. Statistical analysis-related issues

MBR is also limited by factors concerning the statistical analysis. Literature shows that studies often do not employ an intention to treat (ITT) analysis while analysing data rather only show findings of the per-protocol analysis (those participants who followed the interventions as per the protocol), resulting in inaccurate results. This also overlooks the feasibility and acceptability aspects of a meditation-based intervention for various health conditions [ 3 , 26 ]. Hence, the issue of dropouts needs to be addressed more comprehensively. Furthermore, as several factors act parallelly, mediator and moderator analysis, though may be difficult to perform, should be attempted, whenever feasible, to explain and understand the benefits of the interventions [ 26 , 46 ]. Finally, baseline differences between the participants (within the groups or between active and control groups) are often not analyzed.

5. Measures to overcome the methodological limitations with the MBR and the road ahead

5.1. operationalizing the definition of yoga and meditation.

It is highly recommended that the MBR should operationally define the meditation under study (e.g. mindfulness, transcendental meditation), giving due consideration to its ontological definition and psycho-philosophical context [ 14 , 17 , 26 ]. This would ensure research fidelity and replicability of studies across different populations and study designs. Furthermore, the theoretical framework of the meditation should be taken into account while developing any meditation-based interventions and generating a testable hypothesis; this would facilitate the progress of MBR. Most of the research is focused on a specific kind of meditation practice and the research base needs to be widened and be more inclusive.

5.2. Component analysis of the yoga/meditative practice

Meditation involves many preparatory steps (breathing, postures, lifestyles and philosophical changes, etc.) and components (e.g., Qigong meditation includes self-awareness, stilling of the mind, and also raising the Qi energy/prana through a concentrative focus on breath and posture etc.). Hence, it is worthwhile to systematically analyze various components of the meditation (breathing exercises, asanas, chanting, meditation-proper [dhyana], etc.) and also to differentiate between otherwise seemingly similar activities (e.g. exertion due to body moments in Qigong from the exertion during the aerobic exercise), to be able to find out the mechanism of its action and its uniqueness [ 2 , 3 , 23 , 40 ]. Similarly, different modifications of a particular meditation type (e.g. mindfulness-based practices: ACT, MBSR program, MB-CBT, etc.) should be compared among themselves to be able to identify the key component of the modified meditations bringing about the desired benefit. Furthermore, exploration of the non-core component of meditation in various permutations and combinations with the core element of meditation could bring about significant insight into the effect of the individual components of meditations and the most effective combinations among them. For instance, the non-attentional component of mindfulness meditation such as breathing pattern (chaotic Vs rhythmic), sensory involvement (deprivation Vs enhancement), moral discipline, and other contextual effects, etc. should be studied alongside its core component (e.g., attentional and non-reactive engagement with the subjective experiences). One of the potential study designs to realize these objectives are a single-case experimental design where a single participant, usually an expert in meditation, is assessed on multiple occasions after performing different elements of the meditation or different types of meditations [ 47 ]. A similar methodology could also be employed on a small number of participants in an experimental design.

5.3. Participants’ recruitment using the opt-out approach

To overcome the inherent flaw with the participants' recruitment in the MBR and issues with its generalization, some researchers have suggested an opt-out approach to participants' recruitment to be more suitable. This approach has been found to be associated with a higher recruitment rate, adherence rate, and better compliance with the intended meditation-based interventions. Since the opt-out approach require a lesser activation level (required confidence over ones’ ability to change the behavior) and reasonable baseline expectation and interest from the intervention, such participants are more representative of the population, thus making the research findings more generalizable and closer to real-world scenario [ 33 , 34 ].

5.4. Setting up an effective control/comparison group

To decipher the benefits of meditation and compare its impact with other practices or placebo, we need to conduct research having effective control arm(s). Some of the limitations of the wait-list control design (demand characteristics) could be surmounted by employing the dual blinding method (in which the participants are unaware as to which arm of the study is the intervention arm) [ 48 ]. One such example is the health enhancement program, which has been used to serve as a control arm for MBSR [ 49 ]. The latter differed from the MBSR in comprising of music therapy (Vs body scan), nutrition education (Vs sitting meditation), and just walking (vs mindful walking). Other useful strategies could be dismantling strategies (where the practice is systematically broken down into various parts and the key component is replaced by a neutral activity) and by having several comparison groups [ 50 ].

5.5. Adequate description of the study

For the MBR to progress, the researchers must provide adequate descriptions of the study design including the process of obtaining the informed consent; characteristics of the participants, trainers, and the investigator (including their affiliation with any meditation-based organization, experience in meditation, knowledge, and expertise in the field of contemplative sciences, etc.) and most importantly about the meditative practice under study (FA, OM, GM, ASD or mixed; kind of breathing; the level of exertion; modification of the practice based on age and culture of the participants, preparatory steps, etc.) [ 18 , 26 ]. It is also prudent to inform participants beforehand about the meditation-based intervention under study and its potential effect in a neutral yet specific manner. For instance, telling the participants that the technique would ‘train one in stabilizing one's mind’ in place of telling them they are going perform some meditation, would prevent unreasonable expectancies among them, which otherwise could act as a confounder. The researcher can use certain instruments such as credibility and the expectancies questionnaire (CEQ) to assess the baseline expectations of the participants on the effectiveness of the meditation [ 51 ]. Similarly, the fidelity of delivering meditation-based interventions by the instructor could be examined by videotaping the training sessions.

5.6. Ensuring fidelity of intervention delivery

To overcome the issues of the fidelity of delivering meditation-based interventions by the instructors, study protocols must adequately describe the mode of delivery of the intervention, who would provide the intervention, and how?; similarly, pilot testing of the intervention delivery, video-recording of the therapy sessions, feedback from the experts and necessary course corrections become crucial.

5.7. Validating outcomes and measures

The outcomes used to assess the effectiveness of the MBR must be specific and have adequate construct and content validity. Similarly, the outcome measures (questionnaire: self-report or interview-based) developed to assess the effectiveness of the interventions should have criterion validity. It can be achieved by incorporating the theoretical framework of meditation while developing the instruments.

Further, to precisely measure the outcome of meditation, a multi-model approach would be more robust. For example, one may couple the subjective experience of the practitioner (e.g. current level of mind-wandering, affective state, etc.) with an objective measure. One of the useful methods is an ‘Ecological Momentary Assessment’ (EMA), where the practitioner while meditating is asked about his/her current state of mind-wandering and simultaneously given a cognitive task (breath counting or a series of words, etc.) to assess their cognitive performance; such objective measures could also be complemented by a neuro-imaging or electrophysiological studies [ 52 ]. Further, the first persons' account about the meditative experience should be assessed by an experienced third person rather than someone lacking sufficient insights and expertise into the meditation and its effect. This would help in assessing the nuances of the meditative experience of the practitioner. Additionally, the experience of the first person, especially in a novice, can be indirectly assessed by enquiring about his/hers' behavioral change by the second-persons’ account (a family member or an instructor who is also in close terms with the practitioner). This could avoid recall bias and subjective biases while reporting ones' experience, thus provide an accurate result. It should be possible in at least some of the research studies though may be difficult in many others.

5.8. Trait-state interaction and longitudinal assessment of the effect of the yoga/meditation

The effectiveness of the meditation to a larger extent is determined by both the quantity and quality of the meditation practice. Future research must endeavor to capture these aspects, at least over some time, in a practitioners’ routine life. This should also account for the duration of each meditation practices separately if one is involved in more than one type of meditative practices; duration of both the home-based practice and the retreat course; and informal practice during the day to day life (e.g. practicing mindfulness or breathing exercises during the period of stress and cognitive task) [ 26 ]. Moreover, the personality characteristics of the practitioners and other psychological factors that facilitate their persistency in the practice should be assessed. Furthermore, factors related to compliance with the meditation need to be assessed.

The impact of meditation should be longitudinally assessed at different time points. Although it might be difficult, but not insurmountable. To avoid the recall bias, a daily reconstruction strategy could be utilized in which the participants systematically reconstruct their activities and experience of the preceding day [ 53 ]. More robust research design and assessment measures that would be less burdensome and effortless for the participants should be developed to capture the experiences of the practitioners.

5.9. Monitoring for any adverse effects of the yoga and meditation-based interventions

It is not uncommon that various meditative practices are inadvertently advertised as a technique that is free of any potential side-effects and contra-indications, which may not be true for all the meditations and all the participants [ 37 ]. Hence, a robust research methodology should include careful participant selection, explicitly describing the exclusion criterion of the study, and adequately informing the participants about the potential side-effects or adverse effects of the practice while obtaining their consent. Having a mental health professional and yoga expert on board could address this issue to a larger extent [ 26 ]. Till the sound evidence for all meditation-based interventions in mental health problems is established, it is imperative that the individuals, particularly those with mental health problems, should also be adequately informed about the more conventional and evidence-based interventions (e.g., CBT for depressive disorders or aerobic exercise/physiotherapy for the pains).

5.10. Statistical measures

Despite randomization, considerable baseline differences may exist among the participants, such cofactors influencing the response of meditation in the real world should be analyzed by the appropriate statistical tests [ 54 ]. In certain cases, especially when sample sizes are small, it is advisable to provide findings of both the ITT and per-protocol analysis to bring about greater insights into the effectiveness of the interventions. Furthermore, to be able to accurately measure the impact of meditation (e.g. attainment of the mindfulness or level of cognitive performances) on the participants, mediator (e.g. duration of practice, participants’ baseline interest for the meditation, etc.) and moderator analysis (e.g. change in the lifestyles, association with a meditation related organization) should be performed [ 55 ].

6. Limitations

The current review has a few significant limitations. Firstly, we have only included records that are available in English; therefore, we might have missed some of the crucial literature available on native/regional languages, which otherwise could have strengthened the current review. Secondly, most of the included papers were commentaries/perspectives, which were personal accounts of the researchers that might not have undergone strict scientific scrutiny; therefore, the inferences drawn from them might not be conclusive. Lastly, our review was focused mainly on the qualitative aspect of the MBR, including methodological issues, adverse effects with the meditation practice, the effectiveness of the MBI, statistical conundrums, etc. Hence, it could not comment upon quantitative data on the MBR and associated methodological concerns, which otherwise would have been valuable for the readers.

7. Conclusion

MBR has grown exponentially over the last few decades. Meditation-based interventions have been tried extensively for various psychological and medical conditions with some are backed by high-quality research. The ongoing COVID-19 pandemic and its psychological impact have opened a new research avenue to explore the effect of meditation (and meditation-based interventions) on general well-being and for its positive physio-psychological effect in the general public and clinical populations, respectively.

Despite some of the promising findings, MBR suffers from important methodological limitations. Major methodological limitations with the MBR include ambiguity about the definitions of the meditations, lack of testable hypothesis, difficulty with participants’ recruitment, issues with allocation concealment and blinding, difficulties in setting-up the comparative groups, assessing the characteristics of the participants, trainers, and investigators, lack of the validated outcome measures, statistical analysis, etc. However, these limitations are not insurmountable and can be overcome by robust research designs. Future research must take into account these findings while trying to generate evidence for yoga and meditation and interventions.

Authors’ credit statement

SG: Conceptualization ideas, development or design of methodology, maintaining research data, writing initial Draft.

AD: Conceptualization ideas, reviewing draft.

Authors’ disclosure

Dr. Anju Dhawan is a certified teacher of the Art of Living foundation with its head quarter based in Bengaluru, India. She conducts worskshop on Sudarshan Kriya Yoga and Sajah Samadhi Meditation. However, none of the authors report any financial or other incentives from any organization in writing this paper. Nothing to disclose.

Declaration of competing interest

Acknowledgment.

We are grateful to Dr. Suresh Thapaliya, Medical Training Initiative Fellow, RCPsych, Kent and Medway NHS and Social Care Partnership Trust Canterbury, Kent, the UK for his valuable inputs and language editing of the manuscript.

Peer review under responsibility of Transdisciplinary University, Bangalore.

Appendix A Supplementary data to this article can be found online at https://doi.org/10.1016/j.jaim.2022.100620 .

Appendix A. Supplementary data

The following is the Supplementary data to this article:

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Electric Cars Are Suddenly Becoming Affordable

More efficient manufacturing, falling battery costs and intense competition are lowering sticker prices for battery-powered models to within striking distance of gasoline cars.

By Jack Ewing

Alex Lawrence, a dealer in Salt Lake City who specializes in used electric cars, has seen a change over the last year in the kinds of customers who are coming into his showroom. They used to be well-heeled professionals who could drop $70,000 on a Rivian luxury pickup truck.

Recently, Mr. Lawrence said, customers have been snapping up used Teslas for a little over $20,000, after applying a $4,000 federal tax credit.

“We’re seeing younger people,” Mr. Lawrence said. “We are seeing more blue-collar and entry-level white-collar people. The purchase price of the car has suddenly become in reach.”

Regarded by conservative politicians and other critics as playthings of the liberal elite, electric vehicles are fast becoming more accessible. Prices are falling because of increased competition, lower raw-material costs and more efficient manufacturing. Federal tax credits of up to $7,500 for new electric cars, often augmented by thousands of dollars in state incentives, push prices even lower.

At the same time, technology is improving quickly and making electric vehicles more practical. Cars that can travel more than 300 miles on a fully charged battery are becoming common, and charging times are dropping below 30 minutes. The number of fast chargers, which can top up a battery in less than half an hour, grew 36 percent from April 2023 to April 2024.

Carmakers including Tesla, Ford, General Motors and Stellantis, the owner of Jeep, have announced plans for electric vehicles that would sell new for as little as $25,000.

“The E.V. market has hit an inflection point,” said Randy Parker, chief executive of Hyundai Motor America, which will begin producing electric vehicles at a factory in Georgia by the end of the year. “The early adopters have come. They’ve got their cars. Now you’re starting to see us transition to a mass market.”

All this is good news for proponents of electric vehicles and the Biden administration, which is aiming for half of new cars sold to be electric by 2030 as part of the president’s plan to combat climate change. Even if Republicans gain control of the White House and Congress and follow through on promises to dismantle electric vehicle subsidies, they may not be able to undo the market forces pushing down prices.

“There may be some hiccups in the exact pace and scale of E.V. sales if there are major policy changes, but I wouldn’t expect the E.V. market to flatline,” said Peter Slowik, who leads research on passenger cars at the International Council on Clean Transportation, a research organization. “Most automakers are committed to an all-electric future, and many are planning on a timeline that goes far beyond the next administration.”

Electric cars, sales of which have slowed in recent months, are still more expensive than gasoline models, costing an average of $55,252 in the United States in April, according to estimates by Kelley Blue Book. That is a decline of 9 percent from April 2023, but still about $6,700 more than the average for all vehicles.

But Mr. Slowik’s group estimates that cars and sport-utility vehicles capable of traveling 400 miles on a full battery will cost less than cars with internal combustion engines in 2030, even before taking into account government subsidies. (Pickup trucks, which require bigger batteries, will take a little longer, not reaching parity for 400-mile models until 2033.)

Those calculations do not take into account lower fuel and maintenance costs that strengthen the financial argument for electric vehicles. Electricity is almost always cheaper per mile than gasoline, and battery-powered vehicles don’t need oil changes, engine air filters or spark plugs. For people who drive a lot, electric cars may already be a better deal. At the same time, some automakers are offering strong discounts on E.V. models as an enticement for buyers.

While prices are clearly trending downward, there are risks. China supplies more than half of the lithium-ion batteries used in cars sold in the United States, according to Interact Analysis, a research firm. Those batteries will become more expensive because the Biden administration announced in May that it would raise tariffs on them to 25 percent from 7.5 percent.

Many companies are building battery factories in the United States and Canada , but most of these won’t produce enough batteries to replace China for several years.

Raw materials are another risk. The price of lithium and other materials required for batteries has plunged in the last 12 months, making electric cars cheaper. But commodity prices could soar again.

The recent slowdown in the growth of electric car sales has prompted Tesla, Ford and others to delay plans to expand manufacturing. But many analysts expect sales to pick up as a glut of models pushes down prices, and as the charging network grows. High prices and the fear of not being able to find a place to recharge are the two biggest reasons people hesitate to buy an electric vehicle, surveys show.

For many people, the car’s price is not the only expense to consider. People who live in apartments often depend on public charging plugs. Public charging, besides being less convenient, tends to be more costly than charging at home.

Still, the forces pushing prices down are powerful. Manufacturing costs are dropping as traditional carmakers, who were slow to sell electric vehicles, start to apply their decades of experience with mass production to the new technology.

Later this year, for example, General Motors will begin selling an electric version of its Chevrolet Equinox sport-utility vehicle that will have a range of more than 300 miles and sell for less than $30,000 after the $7,500 federal tax credit. And the company plans to sell an even cheaper car, a new Chevrolet Bolt, next year.

The Equinox and Bolt will be built on G.M.’s Ultium platform, a collection of components that can be used for a variety of vehicles including pickups and luxury Cadillacs. G.M., which has cut costs by using the same batteries and parts for different models, has said its electric vehicles will become profitable in the second half of this year.

Electric cars still cost more to manufacture than cars with internal combustion engines, said Prateek Biswas, an analyst at Wood Mackenzie, a research firm. But costs will come down as companies learn how to produce the cars more efficiently, Mr. Biswas said — for example, by eliminating rare minerals from electric motors or replacing copper wiring with aluminum.

At the same time, the cost to make a gasoline car is rising because of stricter emissions regulations. “At some point it will be easier to just move toward E.V.s,” Mr. Biswas said.

Competition is also intensifying. Toyota and other Japanese carmakers with a reputation for delivering reliable and affordable vehicles are belatedly offering electric vehicles. Honda plans to begin producing them at an Ohio factory next year.

There will be more than 100 fully electric models for sale in the United States by next year, according to Cars.com, an online sales platform, double the number available last year. “We’re at the point now where anybody that wants an E.V. for a price point can actually get an E.V.,” said Rebecca Lindland, senior director of industry data at Cars Commerce, which operates Cars.com.

Used car prices are arguably more important than prices of new cars. Most people buy used cars. A vibrant used market vastly increases the number of people who can consider an electric vehicle.

Models from Tesla, Nissan or G.M. have been on the road for three years or more, generating inventory for dealers as the original owners buy new ones. More than half of the used electric vehicles on the market sell for less than $30,000, according to Recurrent, a research firm that focuses on the used E.V. market.

Jesse Lore, owner of Green Wave Electric Vehicles in North Hampton, N.H., recently sold a used Chevy Bolt for $15,000. After applying a federal tax credit for used electric vehicles, the price was $11,000. Besides the lure of affordable prices, he noted, his customers like that electric vehicles are quieter than gasoline models, better for the environment, and faster because an electric motor generates instant torque.

“The car is more fun than whatever they’re driving now,” Mr. Lore said.

Jack Ewing writes about the auto industry with an emphasis on electric vehicles. More about Jack Ewing

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