New Book


From the Preface

[An ESP experiment] “immediately appeals to his [or her] unconscious readiness to witness a miracle, and to the hope, latent in all [people], that such a thing may yet be possible. Primitive superstition lies just below the surface of even the most tough-minded individuals, and it is precisely those who most fight…” 

C.G. Jung, 1952.

It is of natural science to investigate nature, impartially and without prejudice.

J.R. Smythies, 1967.


  • something that defies explanation – adds spice. Beyond spice, anomaly offers hope, the hope that something – whatever it may be – exists beyond the everyday. We humans live in hope eternally. But what exactly is an ‘anomaly’? I do not mean the kind of oddness or peculiarity in human behaviour that is everywhere to be seen. I am referring to things that really should not be so, the weird, the spooky, the face in the mirror that isn’t you. Anomalistic experiences are curious, strange, ‘funny peculiar’.  As we engage with the experience itself, we freely ruminate and craving to understand, we dig to discover something new. The goal here is to do precisely that, to dig below the surface of anomalistic experience, to take a close look at the psychology of the paranormal, to put psi ‘under the microscope’.  One should not be surprised if all is not as it seems and we can expect surprises aplenty here.

I approached the writing of this book with anticipation

wondering where the adventure might lead. I hoped it would lead towards new insights, explanatory theory and nuggets of new knowledge.

In the end, I reached an altogether unexpected conclusion…

How, you may well ask, can that be?  Surely, an ‘expert’ about psychology and the paranormal should already have reached an opinion one way or the other, a strong point of view?

Not so.

I genuinely have no idea where this new investigation will lead.I write as a zetetic.[1] I have a map and a set of place names[2],  but what exists at each place is uncertain. I last visited this field 20 years ago. Now, with ‘new eyes’ and new evidence, one’s understanding could be significantly different compared to 20 years ago.  Unlike previous visits, I am giving the psi hypothesis an initial probability of being a real, authentic and valid experience of 50%.

Please take a minute to consider your own current degree of belief in ESP.  Indicate your current belief with an arrow on the Belief Barometer below.[3]

My objective

is to cut a path through the vast, tangled jungle of publications with a machete that is sharp and decisive. With each new claim, one must reads, reflect, question, reflect some more, and ultimately decide at one particular moment the degree of plausibility that each specific claim possesses. Belief Barometers will be used to mark your and my degree of belief for each individual claim. The amount of variation in one’s degree of belief indicates a sensitivity to evidence.  If somebody simply says ‘0%’’ or ‘100%’ to absolutely everything, that surely indicates intransigence and intolerance of ambiguity.

One cannot profess definite explanations in advance because that would be blinkered. If we already KNEW the answers, we would cease to investigate, I would not be writing, and you would not be reading. The truth would already be out and we would be picking at the flesh of dead learning like vultures at a dead elephant.

No true zetetic starts from a fixed position. She/he suspends judgement while seeking and exploring with an open mind. In any science, all ideas are provisional, pending further investigation. Those who assert a fixed point of view before looking at the evidence break the ‘Golden Rule of Science’, which is to let conclusions follow the evidence.

Anomalistic psychology

includes the entire spectrum of conscious experience in all of its glorious splendour. By examining in-depth the evidence both pro and con any particular claim, one gains an entitlement to offer conclusions. Even then, the conclusions are tentative, pending further investigation by independent investigators. I am also minded to recall Heraclitus’ well-known dictum, “You cannot step into the same river twice, for other waters are continually flowing on.”  Having stepped into the paranormal river on a few occasions, it was each time a different river.

It is impossible here to include everything in Anomalistic Psychology. The selected exemplify phenomena that have received significant attention from researchers over the last 50 years.  Fun though they may be: Big Foot, the Loch Ness Monster, Clever Hans, mediums, Ouija boards, and stage mentalists didn’t make the cut. See them in the ‘red tops’ and on YouTube.

Returning to the world of psi

after a 20-year respite, I am curious to see what has changed. Anomalistic Psychology is now the battle-ground of psi (Luke, 2011) and there is a growing stockpile of sophisticated methods and findings that can be considered to be supportive of paranormal interpretation.

My return to the field is not without some amount of trepidation, for now I risk being the target for pot-shots from both sides!

However, a strongly partisan view is unhelpful to making any progress in this, or any other part, of science.  Progress requires a dialogue between advocates of differing positions. I wish to put down a marker that says: “Peace. Nobody won. Stop fighting.” That’s not to say there won’t be criticism; there must be, otherwise there can never be progress.

To establish a dialogue, I invited seven *stars* of the field to respond to my criticisms and questions: Daryl Bem, Susan Blackmore, Stanley Krippner, Dean Radin, Hal Puthoff, Rupert Sheldrake, and Adrian Parker. Warm thanks to one and all.

Evidence, critique, new theories

In this book, I present evidence, critique, and new theories. Whenever possible, I use verbatim quotations of advocates concerning specific claims. Nobody can ever legitimately say that a claim has been ‘disproved’; if the truth of a claim is undecided, it is only possible to say that it is neither confirmed nor disconfirmed.

Whatever one thinks, the world is always independent of how we might wish it to be. There is nothing wrong about believing in psi if one chooses to, and scientists have no place disparaging such beliefs. Belief in the paranormal is normal.

Sociologist Andrew Greeley (1991) put it this way:

“The paranormal is normal. Psychic and mystic experiences are frequent even in modern urban industrial society. The majority of the population has had some such experience, a substantial minority has had more than just an occasional experience, and a respectable proportion of the population has such experiences frequently. Any phenomenon with incidence as widespread as the paranormal deserves more careful and intensive research than it has received up to now….People who have paranormal experiences, even frequent such experiences, are not kooks. They are not sick, they are not deviants, they are not social misfits, they are not schizophrenics. In fact, they may be more emotionally healthy than those who do not have such experiences.” (Greeley 1975: 7)

Scientists should be agnostic about the ontological status of paranormal experience and examine the circumstances that constrain or facilitate exceptional experiences.  In approaching each claim, I maintain a zetetic viewpoint, neither believing nor disbelieving,  attending to the evidence. Only after one has completed a thorough survey of evidence is one entitled to an informed opinion. A zetetic must not be naïve, however.

Master zetetic, Marcello Truzzi (1987):


“The ground rules of science are conservative, and in so far as these place the burden of proof on the claimants and require stronger evidence the more extraordinary the claim, they are not neutral. But, we also need to remember, evidence always varies by degree, and inadequate evidence requires a tolerant reply which requests better evidence, not a dogmatic denial that behaves as though inadequate evidence were no evidence” (p. 73).

Astronomer, Carl Sagan (1995) also offers wise advice:


“It seems to me what is called for is an exquisite balance between two conflicting needs: the most skeptical scrutiny of all hypotheses that are served up to us and at the same time a great openness to new ideas. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of these modes, whichever one it is, you’re in deep trouble.If you are only skeptical, then no new ideas make it through to you. You never learn anything new. You become a crotchety old person convinced that nonsense is ruling the world. (There is, of course, much data to support you.) But every now and then, maybe once in a hundred cases, a new idea turns out to be on the mark, valid and wonderful. If you are too much in the habit of being skeptical about everything, you are going to miss or resent it, and either way you will be standing in the way of understanding and progress. On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in you, then you cannot distinguish the useful as from the worthless ones.” (Sagan, 1995, p 25).

The first 20 years of the 21st century

brought many astonishing scientific discoveries: the first draft of the Human Genome, graphene, grid cells in the brain, the first self-replicating, synthetic bacterial cells, the Higgs boson, liquid water on Mars and gravitational waves. Not bad going in such a short time!  During this same period, Anomalistic Psychology has grown at an enormous pace with increased numbers of investigators and publications (Figure P2).  Disappointingly, however, new discoveries or theories are few and far between. If there has been one discovery, it might be stated thus: The science of anomalistic experience is more complex and obscure then most psychologists ever imagined. When we are at the beginning of new venture like this, we must not be deterred by having no real answer to two of the hardest questions in science: What is consciousness and what is it for? [5]

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One of the greatest scientific minds of the last century, Stephen Hawking, stated:


“Science is beautiful when it makes simple explanations of phenomena or connections between different observations” (Sample, 2011).

It has also been said that advances in science come not from empiricism but from new theories.

Parapsychology, like its ‘big sister’ Psychology, has always been heavily empirical and short on theory. The rapid growth is indexed by multitudes of empirical studies in the absence of notable theoretical developments.

By becoming more theory-driven, the field of ‘Psychology + Parapsychology’ as an integrated whole seems likely to make faster progress.

It seems counterproductive to treat Parapsychology and Psychology as separate fields.

Bringing the ‘Para’ part back into mainstream Psychology helps to integrate the discipline. This book takes a step in that direction. Parapsychology and Psychology contain myriads of variables, A,B,C…N…X,Y,Z.  An established strategy for developing new research in Psychology and Parapsychology is for the investigator to identity ‘gaps’ in the field and to set about filling those gaps with correlational and experimental studies with almost every possible permutation and combination of variables.  The gap filling approach is one strategy for keeping productivity high but, often, it is at the expense of developing new theories. As already noted, the academic world is based on quantitative measures of performance[6] and the number of publications a researcher can claim matters. This drive towards publications leads to what I call ‘Polyfilla Science’.

Polyfilla Science

For every ‘hole’ investigators can fill, they are almost guaranteed a peer-reviewed publication. ‘Polyfilla Science’ exists on an industrial scale, keeping hundreds of thousands of scientists busily occupied in hot competition. The ‘winners’ of the Polyfilla competition are the ones who tick the highest number of boxes and harvest the most citations.[7]

‘Polyfilla Science’ can be represented as a multidimensional matrix of cells where the task of science is viewed as filling every last cell in the matrix (Figure P3).  This method of doing science is more akin to a fairground shooting gallery than to theory-driven science.  In the absence of theory, many researchers use a Polyfilla ‘shotgun’ by testing a dozen or more “hypotheses” in one shot. Popular though it is, ‘Polyfilla Science’ isn’t the only game in town, and a theory-driven approach is also available.  Theory is used to identify the principles behind questions that need answering in a process of confirmation and disconfirmation of predictions. When one considers the fact that there are one hundred thousand psychology majors in the US alone, all needing a research project, it is no wonder the Polyfilla approach is so popular.[8]

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The book is geared towards the needs of teachers, researchers and students interested in Anomalistic Experience, Parapsychology and Consciousness Studies.

In comparison to the scientific discoveries in other fields, Psychology or Parapsychology have made no world-changing discoveries in the last 50 years. By this, I mean discoveries that are worth telling your grandchildren. In my opinion, the lack of significant theoretical developments, and the Polyfilla Approach, are two of the main reasons for this lack of progress.  All this needs to change.

Avoiding the drunkard’s search

One must beware – and avoid – the drunkard’s search principle – searching only where it is easiest to look. You probably already know the parable:

A policeman sees a drunk man searching for something under a streetlight and asks what the drunk has lost. He says he lost his wallet and they both look under the streetlight together. After a few minutes the policeman asks if he is sure he lost it here, and the drunk replies, no, and that he lost it in the park. The policeman asks why he is searching here, and the drunk replies, “this is where the light is”.


We must look wherever psi could be found, not only where it is easiest to look.

The search for psi is a complex, winding trail of traps and pitfalls. When we observe evidence, we must not,  a priori, rule it out as subjective validation or confirmation bias. An openness to being wrong may cause uncomfortable feelings, but knowledge and truth are never givens. When we are lucky enough to discover something new, this is hard-won treasure.

I present here new theories in the spirit of open inquiry. There’s a saying that ‘today’s theories make tomorrow’s fish-n-chip paper’. Possibly, probably, these theories are wrong.  So be it. If possible, falsify my theories, throw them out, and develop better ones. By testing and falsifying existing theories, newer, better theories can be obtained and so on indefinitely. As I share thoughts and conclusions, the reader will be able to contest and challenge  and contrary evidence.

We’ve walked on the Moon and are heading to Mars, but we still don’t yet know the function of consciousness. One of the starting points must be to separate fact from fiction in anomalistic psychology.


[1] Zetetic from the Greek zçtçtikos, from zçteô [ζητέω (zéteó) — to seek] “to seek to proceed by inquiry”.

[2] [2] Tópos, the Greek name for “place” (τόπος); ‘topic’ in English.

[3] Belief Barometers appear throughout this book.

[4] The majority of so-called ‘skeptics’ are disbelievers and/or deniers who have adopted the label ‘skeptic’ for its more temperate connotations. The late Marcello Truzzi was one of two co-founding chairman of the leading US skeptical organisation CSICOP (the Committee for the Scientific Investigation of Claims of the Paranormal). Truzzi became disillusioned with the organization, saying they “tend to block honest inquiry, in my opinion… Most of them are not agnostic toward claims of the paranormal; they are out to knock them.” Using the title of ‘skeptic’, Truzzi claimed that this association of debunkers could claim an authority to which they were not entitled: “critics who take the negative rather than an agnostic position but still call themselves ‘skeptics’ are actually pseudo-skeptics and have, I believed, gained a false advantage by usurping that label.” Genuine or ‘classical’ skepticism is the zetetic view to suspend judgement and enter into a genuine inquiry that assumes any claim requires justification. Maintaining a zetetic position of open inquiry requires a steady hand and a critical mind. There is no room for naivety but a touch of Socratic irony may at times be helpful. A protracted correspondence between Martin Gardner and Marcello Truzzi , indicating their two contrasting viewpoints, has been published by Richards (2017).

[5] Nagel (2013) and Strawson (2006), among others, argue for the ancient philosophy of pan-psychism, in which all physical objects from atoms to the cosmos all have conscious experience.  Elsewhere, I have described Consciousness  as “a direct emergent property of cerebral activity” (Marks, 2019)..

[6] Numbers of publications, citations, grant monies, prizes, promotions and awards.

[7] One of the world’s most published and ambitious ‘Polyfilla’ psychologists told me a self-effacing story about the occasion he went for an interview at the University of Oxford. A member of the panel asked: “Dr X, you have a huge number of publications. But what does it all mean?” He didn’t know the answer and got rejected for the post.

[8] Polycell Multi-Purpose Polyfilla Ready Mixed, 1 Kg, i#1 best seller on, 16 May 2019.

[9] The history of the field is adequately reviewed by others e.g. John Beloff (1993) or Caroline Watt (2017).

A General Theory of Behaviour IV: Entrainment, Rhythm and Synchronicity


The fourth part in a series about A General Theory of Behaviour. I examine homeostasis, synchronicity and circadian systems in the regulation of arousal, behaviour and sociality.


This is a beautifully engineered system where homeostatic and circadian influences at multiple levels are integrated to permit optimal integration of mediators in the internal milieu and external world.

Silver and LeSauter, 2008, p. 272


Flashing fireflies, singing cicadas, parading flamingos, murmurating starlings, marching soldiers, chanting sports fans, and crowd participation at rock concerts – all have something in common. To varying degrees, they have  ‘got rhythm’ –  a shared, synchronized, irresistible rhythm of entrainment.

Entrainment is manifested by an endogenous rhythm that is synchronized with an external cycle such as the light-dark cycle with the result that both oscillations converge towards the same frequency. Behavioural entrainment involves a dynamic coupling of behaviour and brain activity between two or more individuals, which may include ‘mirroring’ [1] or other forms of coordinated joint action. In this post I examine the contribution of entrainment, rhythm and synchrony to individual and social behaviour.

Entrainment is a biological construct borrowed from classical mechanics. It is alleged that, in 1666, the Dutch scientist Christiaan Huygens noticed that when two pendulum clocks are set on the same flexible surface, they eventually become synchronized. This interesting phenomenon has been observed with many kinds of devices and also in living organisms that exhibit rhythmic behaviour with a periodic oscillation. Two necessary conditions for rhythmic synchronicity to qualify as entrainment are: (i) at least two autonomous oscillating systems must be present; and (ii) the two systems must interact.  The first condition, autonomy, differentiates entrainment from resonance, an increase in an object’s natural frequency amplitude following exposure to another object with a similar frequency. The oscillations of a resonating system cease when the influence of the original impulse emitting system is removed while an entrained oscillation continues.

Over hundreds of millions of years in an environment that changes dramatically over every 24-hour cycle, evolution has produced universal rhythms throughout the plant and animal kingdoms such that each organism’s biochemistry, physiology, and behaviour are organized in diurnal cycles. Many circadian rhythms are persistent even in the absence of the normal diurnal cues of night and day or temperature changes, e.g. while living in caves.  Such demonstrations are interpreted as reflecting the operation of an internal biological clock or clocks. The circadian clock system serves as a biological ‘alerter’ that lets us know when significant events are due to happen.

Principle V (Entrainment): The internal CLOCK controls physiological and behavioural processes in synchrony with regular changes in the environment.[2]

Figure 2Figure 1. The circadian clock and disease. Relationships and interactions between the circadian clock and disease may either be direct or indirect via behaviour and/or sleep (for description of arrow numbers see main text). Social schedules exert their influence on physiology mainly via behaviour (arrow S). The regular daily changes in the environment that the clock uses for its synchronisation (entrainment) to the 24-h world are indicated by arrow Z. Reproduced with permission from The Circadian Clock and Human Health’ by Till Roenneberg & Martha Merrow (2016).

The light-dark (LD) cycle is the most reliable of the external signals enabling entrainment[3] and is referred to as a zeitgeber (i.e. time-giver). LD information is perceived by mammals with retinal photoreceptors and conveyed directly to the suprachiasmatic nucleus (SCN) of the hypothalamus, where it entrains oscillators in what is regarded as the master clock of the organism [4]. Other cyclic inputs, such as temperature, noise, social cues, or fixed mealtimes, also can act as entraining and predictive agents, although usually to a less reliable extent than LD.

An entrainable circadian clock is present in the SCN during fetal development and the maternal circadian system coordinates the phase of the fetal clock to environmental lighting conditions. Even before birth, the organism is entrained to the LD cycle.[5]

Having a CLOCK system is advantageous for predicting and preparing for important events.  When food is available only for a limited time each day, it has been observed that rats increase their locomotor activity 2 to 4 hours before the onset of food availability [6]. Similar anticipatory behaviour occurs in other mammals, and in birds, accompanied by increases in body temperature, adrenal secretion of corticosterone, gastrointestinal motility, and activity of digestive enzymes.[7]

It has been proposed that a common design principle applies to the CLOCK in all organisms, from bacteria to humans, and that the circadian clock has existed for at least 2.5 billion years.[8]  The predictive mechanism in which physiology and behaviour are ‘tuned’ to the timing of external events allows a competitive advantage.


A zeitgeber can entrain or synchronize an organism’s biological rhythms to the 24-hour LD cycle and 12-month seasonal cycle. Normal circadian rhythms depend upon zeitgebers. When zeitgebers are absent, for example, when a person is placed in a cave or a windowless room, an endogenous rhythm with a period close to that of the Earth’s rotation is provided.

The human CLOCK system consists of a ‘master clock’ in the SCN of the hypothalamus and secondary clocks in different bodily organs. The endocrine system regulates the circadian rhythm and sleep/waking cycle by producing regular hormone releases. Melatonin is produced in the pineal gland under the control of the central circadian pacemaker in the SCN. Melatonin production is low in the light of day and high during the dark of night when it induces and supports sleep. Melatonin supplementation can be used for the treatment of winter depression, sleep disorders, and as a therapy for epilepsy.

Precise estimates of the periods of endogenous circadian rhythms of melatonin, core body temperature, and cortisol in healthy individuals show that the period of the human circadian clock averages 24.18 hours.[9] Cell-autonomous clocks consist of a ‘transcription–translation-based auto-regulatory feedback loop’.[10]

The coupling of internal and external changes by entrainment enables the organism to predict environmental changes. In humans, the circadian rhythm of melatonin production by the pineal gland and of core body temperature are good markers of circadian rhythms when collected under constant conditions. These markers are closely associated with the circadian component of the sleep-wake rhythm as well as with the circadian variation in neurobehavioural performance. [11]

Body temperature reflects predominantly the CLOCK and neurobehavioral functions are affected by a sleep pressure homeostasis which increases with time awake and may contribute to the phase delay through interaction with the circadian clock. Neurobehavioral functions usually show a circadian decline at night as is observed in CBT, but they continue their decline after CBT begins to rise, making the subsequent 2–6 hour period (clock time approximately 0600–1000) a zone of maximum vulnerability to loss of alertness and to performance failure.[12]

Sleep homeostatic pressure is produced by the SLEEP-REF, which is indexed behaviourally by intensified feelings of sleepiness that occur the longer the time we are awake. Sleep pressure automatically increases during wakefulness and declines during sleep and the feeling of sleepiness that it generates enables us to keep our wake-sleep balance in equilibrium. To some degree sleep pressure can be placed under voluntary control. We can force ourselves to remain awake when there is a strong reason to do so. In addition to subjective sleepiness, sleep homeostatic pressure is indicated by electroencephalographic (EEG) slow wave activity (SWA), which is prominent early in sleep but decreases over the course of sleep.  We return to sleep homeostasis in a later post.

Millions of years of evolution have equipped living organisms with two versatile systems that are designed to fine-tune tasks of daily living such as eating, drinking, eliminating, mating and sleeping, with the outside environment. By entraining essential activities to environmental zeitgebers, the CLOCK schedules the servicing of daily needs at optimal and non-overlapping times. In parallel, the REF provides corrective responses to the organism’s continuously changing needs including any unexpected challenges that may come over the horizon.  These two complementary systems seamlessly regulate the waking-sleeping cycle and integrate the internal milieu with the contingencies of the proximal world.[13] The CLOCK and REF systems successfully moderate levels of alertness enabling behaviour to be controlled and executed in a coordinated and coherent manner. To quote Silver and LeSauter (2009):  “This is a beautifully engineered system where homeostatic and circadian influences at multiple levels are integrated to permit optimal integration of mediators in the internal milieu and external world” (p. 272).


As if the advantages of the CLOCK and REF were not already enough, they also provide a fringe benefits. The most important is that they are responsible for a lot pure, unadulterated fun. When people share stories, singing, dancing, ceremonies, rituals and rites of passage, they experience special feelings of joy, social cohesion and fulfilment.

Principle VI (Coalescence): Entrainment and synchronicity occur in shared activity to create cooperation, cohesion and social bonding.

Behavioural entrainment and synchronization in movement, vocalization or beat enable people to match their actions in timing and rhythm and it is this synchronized form of matching that seems to be most beneficial to enjoyment.[14] Many types of joint action transition naturally towards synchrony such as smiling, laughing, cheering, dancing, marching, drumming, stamping, clapping, singing and chanting are all aspects of sociality that contain elements of synchonicity and/or rhythm. When Ed Sheeran packs a stadium of fifty thousand fans and invites them to sing along with him, they absolutely love it and come back for more.  Other social behaviours carried out on a reciprocal basis such as conversation, reciting, poetry reading, playing musical instruments in a band or orchestra involve similar levels of shared appreciation of timing and rhythm: The universality of synchronised action across time and space suggests an evolutionary advantage. Apart from having fun, synchronised shared action offers the advantage of increased social cohesion. [AP 014].

Synchrony in all of these types of group performance involves sharing of intentionality in the deliberate production of rhythmic joint actions.[15]  Reinforcement of synchrony by the building of trust and cooperation flows from the group performance of music, chanting, drumming or dance and cooperative actions are reinforced by increasing levels of synchrony.  Indigenous music and dance facilitates synchrony and strengthens cooperative action and social cohesion.[16] Enjoyment of music and dance as performers or observers is universal to human beings. [AP 015].

When individuals participate in musical performances, even only as observers, any form of  joint action involves affective entrainment.[17]  More seems to be going on here than simply temporal entrainment because there is a strong affective tone. [18]  Group drumming is known to produce endocrinal and immunological responses that indicate relief of stress.[19]

Affective entrainment of rhythm and beat are associated with interpersonal bonding initiated by the pleasure of moving the body to music and keeping in time with others. The affective components of entrainment are  associated with temporal synchronization creating a ‘groove’ which carries a sense of affiliation.[20] This shared trance-like enjoyment can lead to ‘manic’ form of appreciation such as occurred with the “Beatle-mania” of the 1960s.[21]



Jackson et al. investigated the effects of synchrony and physiological arousal on cohesion and cooperation in large naturalistic groups.[22]  They manipulated the synchronous and physiologically arousing affordances of a group marching task within a sports stadium with large samples of strangers.  Participants’ subsequent movement, grouping, and cooperation were observed via a camera hidden in the stadium’s roof. Synchrony and arousal both showed main effects, predicting larger groups, tighter clustering, and more cooperative behaviour. Synchrony and arousal among participants in cultural rituals strengthen social cohesion. [AP 016].

The origins of social-affective entrainment appear in early-life musical and rhythmic interactions between infants and caregivers e.g., rocking of the cradle, rhythmic ‘baby talk’ and singing of lullabies.  When individuals exchange information reciprocally about each other’s mental processes, alignments unfold over time and space, creating a special form of social interaction, an intrinsically shared activity.[23] Alignment of words, thoughts, bodily postures and movements are all forms of “social entrainment” that can produce increases in positive affect, social cohesion and bonding. [AP 017].

Social entrainment can be detected at many levels both physical to the mental.  Gallotti, Fairhurst and Frith argue that interacting individuals are dynamically coupled. When people participate in cultural events such as concerts, plays and operas, alignment is detected in brain activity of the participants. Socio-affective entrainment involves continuous mutual adaptation, complementarity, reciprocity and a division of labour including leader–follower roles.[24] As we shall see, social forms of entrainment conspire to bond people together. Cultural events such as concerts, plays and operas, there is an alignment both in brain activity and behaviour of the participants.  [AP 018].


  • An entrained circadian CLOCK, which is universal to living organisms, synchronizes internal physiology and external behavior with the light-dark cycle and other zeitgebers.
  • The predictive CLOCK and reactive REF coordinate behaviour and physiology, including continuous modulation of alertness, waking and sleep.
  • Socio-affective entrainment synchronizes shared cultural activities and reinforces social cohesion and bonding.


[1] Mirroring occurs when one member of a couple does the same thing as the other member, at the same time.

[2] For simplicity’s sake, we will call the ‘internal circadian clock system’ the ‘CLOCK’.

[3] Entrainment can be understood as a form of classical conditioning.

[4] Stokkan, K. A., Yamazaki, S., Tei, H., Sakaki, Y., & Menaker, M. (2001). Entrainment of the circadian clock in the liver by feeding. Science291(5503), 490-493.

[5] Reppert, S. M., & Schwartz, W. J. (1983). Maternal coordination of the fetal biological clock in utero. Science220(4600), 969-971.

[6] Mistlberger, R. E., & Rechtschaffen, A. (1984). Recovery of anticipatory activity to restricted feeding in rats with ventromedial hypothalamic lesions. Physiology & behavior33(2), 227-235.

[7] A conservation project at Victoria Falls Safari Lodge in Zimbabwe provides meat to vultures every day at 1 o’clock. Dozens of vultures roost nearby for a few hours every day before feeding time.

[8] Loudon, A. S. (2012). Circadian biology: a 2.5 billion year old clock. Current Biology22(14), R570-R571.

[9] Czeisler, C. A., Duffy, J. F., Shanahan, T. L., Brown, E. N., Mitchell, J. F., Rimmer, D. W., … & Dijk, D. J. (1999). Stability, precision, and near-24-hour period of the human circadian pacemaker. Science284(5423), 2177-2181.

[10] Takahashi, J. S. (2016). Transcriptional architecture of the mammalian circadian clock. Nature Reviews Genetics.

[11] Cajochen, C., Chellappa, S., & Schmidt, C. (2010). What keeps us awake?—the role of clocks and hourglasses, light, and melatonin. In International review of neurobiology (Vol. 93, pp. 57-90). Academic Press.

[12] Goel, N., Basner, M., Rao, H., & Dinges, D. F. (2013). Circadian rhythms, sleep deprivation, and human performance. In Progress in molecular biology and translational science (Vol. 119, pp. 155-190). Academic Press.

[13] Silver, R., & LeSauter, J. (2008). Circadian and homeostatic factors in arousal. Annals of the New York Academy of Sciences1129(1), 263-274.

[14] Reddish, P., Fischer, R., & Bulbulia, J. (2013). Let’s dance together: Synchrony, shared intentionality and cooperation. PLoS ONE, 8(8), e71182. journal.pone.0071182.

[15] Reddish et al. (2013) experimentally examined the importance of shared intentionality in reinforcing cooperation from group synchrony.

[16] Mogan, Fischer and Bulbulia (2017) meta-analyzed 42 studies of synchrony effects on: (1) prosocial behaviour, (2) perceived social bonding, (2) social cognition, and (3) positive affect. Synchronous actions affected all four domains and synchrony in larger groups increased prosocial behaviour and positive affect, but did not influence synchrony effects on perceived social bonding and social cognition. See: Mogan, R., Fischer, R., & Bulbulia, J. A. (2017). To be in synchrony or not? A meta-analysis of synchrony’s effects on behaviour, perception, cognition and affect. Journal of Experimental Social Psychology72, 13-20.

[17] Musical entrainment appears in different species within the animal kingdom, e.g. synchronization to a beat in a sulphur-crested cockatoo (Cacatua galerita eleonora). Schachner, A., Brady, T. F., Pepperberg, I. M., & Hauser, M. D. (2009). Spontaneous motor entrainment to music in multiple vocal mimicking species. Current Biology, 19(10), 831-836).

[18] Phillips-Silver, J., & Keller, P. (2012). Searching for roots of entrainment and joint action in early musical interactions. Frontiers in human neuroscience, 6, 26.

[19] Bittman, B. B., Berk, L. S., Felten, D. L., Westengard, J., Simonton, O. C., Pappas, J., & Ninehouser, M. (2001). Composite effects of group drumming music therapy on modulation of neuroendocrine-immune parameters in normal subjects. Alternative therapies in health and medicine7(1), 38.

[20] Janata, P., Tomic, S. T., and Haberman, J. (2012). Sensorimotor coupling in music and the Psychology of the groove. J. Exp. Psychol. Gen. 141, 54–75. This study suggested that perceptions of ‘being in the groove’ depend on a strong underlying beat, feeling a part of the music, and wanting to move with the beat.

[21] Like the Beatles, the fans of Franz Lisz, the Hungarian pianist, are claimed to have displayed ‘mania’.

[22] Jackson, J. C., Jong, J., Bilkey, D., Whitehouse, H., Zollmann, S., McNaughton, C., & Halberstadt, J. (2018). Synchrony and Physiological Arousal Increase Cohesion and Cooperation in Large Naturalistic Groups. Scientific reports8(1), 127.

[23] Gallotti, M., Fairhurst, M. T., & Frith, C. D. (2017). Alignment in social interactions. Consciousness and cognition48, 253-261.

[24] Hasson, U., & Frith, C. D. (2016). Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions. Phil. Trans. R. Soc. B371(1693), 20150366.