Tuesday, November 23, 2010

Did Meditating Make Us Human? -- by Matt J. Rossano

Matt Rossano’s article provides an interesting contrast to our previous two posts extracting Thomas Metzinger’s article on out of body experiences. Altered states here are seen as a prelude to the evolutionary development via Baldwinian selection of working memory and eventually the ability to symbolize, which characterizes modern humans. Rossano is a professor of Psychology at University of Southeastern Louisiana University. He is a frequent contributor to the Huffington Post (Link). His recent book is SUPERNATURAL SELECTION : HOW RELIGION EVOLVED, and a list of his recent publications can be found here. The original article contains more extensive citations.


The thesis of this article is that this commonplace activity, which I will call campfire rituals of focused attention, created an important selective pressure in the evolution of the modern human mind. Ritualized gatherings before an open fire — repeated night after night, generation after generation for thousands of years — contributed significantly, though not necessarily exclusively, to the evolution of the enhanced working memory capacity required for symbolic thinking.

The scenario is grounded in the following five propositions.


1. Convincing evidence of symbolism in the form of ceremonial tools, artwork and grave goods appears late in the archaeological record (largely after 50,000 bp) and post-dates the emergence of anatomically modern humans.

Late emergence of symbolism

In this article, ‘symbolism’ is Peirce’s definition, arbitrary referents based on cultural convention. Peircian symbolism is what appears to have arrived late in the archaeological record and it is this that required enhanced working memory. Genetic and fossil evidence points to the emergence of anatomically modern humans (Homo sapiens sapiens) somewhere between 200,000 and 150,000 years bp in Africa . Some have argued that the relatively sudden appearance of sophisticated tools, burial with grave goods, and image-making in the European Upper Palaeolithic signifies a ‘revolution’ in human thought and behaviour . Peircian symbolism most likely did not occur until the Upper Palaeolithic, when grave goods, sophisticated tools, image making and what appear to be purely ceremonial artifacts arrive on the archaeological scene. For the purposes of the current model, what is pivotal is that the evidence for this‘higher-level’ symbolism emerges late and post-dates the arrival of anatomically modern humans.


2. Recent work combining cognitive science and archaeology has built a compelling case for explaining the late emergence of symbolism as the result of a fortuitous genetic mutation (or combination of mutations) that enhanced human working memory capacity.

Fortuitous Mutation (s)

The ultimate mechanism [responsible for symbolism] must come down to a fortuitous genetic mutation that reorganized brain structure and function, thus giving Homo sapiens a cognitive advantage over other archaic hominin forms . While Klein typically talks in terms of a single genetic mutation (terminology, which for simplicity’s sake, I will retain), this change could have involved a series of mutations that affected the interaction of genes and, or, their manner of expression. Coolidge & Wynn (2001...) have elaborated on Klein’s proposal, arguing that the most likely target of this mutation would have been an enhancement of working memory capacity. In this context, working memory capacity refers to the ability to hold information in mind, especially information about behavioural procedures and intended goals, in spite of interfering stimuli or response competition .

Enhanced working memory capacity, however functionally envisioned, is a prerequisite to the emergence of symbolism. Our ancestors had an enhanced capacity to recall, consciously retain and manipulate information. This enhanced working memory capacity was essential to crossing the threshold to purely arbitrary or convention-based symbolism . To understand this level of purely arbitrary reference, one must be able to hold in mind both what the signifying image is perceptually and what it means conceptually, while at the same time understanding that these two are not the same.

The exact time of emergence is less important than when this change became widespread, which, I would argue, was not until around 50,000 bp, immediately prior to the emergence of symbolism.


3.Evolutionary developmental biology indicates that genetic adaptation can sometimes follow somatic adaptation (the Baldwin effect). Put another way, environmental conditions that require bodily adaptation (such as high-altitude conditions which require the production of more red blood cells) simultaneously create selection pressure for genetic mutations that more permanently establish the adaptive phenotypic state.

The Baldwin effect updated

Environmentally induced somatic modifications (resulting from either learning or physiological adaptation) ... become heritable changes. According to this principle, acquired traits do not directly affect genes but these traits could create or importantly contribute to selective conditions that would, in time, genetically establish them in the population.... In other words, an initially environmentally induced trait eventually became encoded and transmitted genetically. .

This could provide a model for how hominins acquired increasingly complex cognitive skills. These skills may first have appeared as novel acquired traits induced by atypical environmental demands. Then, as those demands persisted, a Baldwinian process could have led to the traits becoming genetically heritable and stabilized. Over the course of hominin evolution, the atypical environmental demands were increasingly products of hominins themselves.

Wright (2004) has recently reviewed a range of studies providing support for the process of ‘stress-directed mutagensis’, where feedback mechanisms within the organism allow environmental stressors to target specific genes that must mutate in order to surmount the stress. Though a great deal is still to be learned about how mutations arise, it is becoming increasingly clear that dismissing them as simply random is too simple.

Modifications are more likely to arise in those systems that are under selection pressure — where the adaptive range of a physiological system is under stress. Any mutation or genetic reassortment that resets the range of a physiological system to a more adaptive level would then be positively selected by environmental conditions. Thus, a population of humans relocated to higher altitudes is biased toward the expression of any mutation that permanently resets their baseline levels of red blood cell production.


4. Neuroscience studies indicate that meditation produces short-term and long-term effects on both the structure and function of those areas of the brain closely associated with working memory and focused attention such as the dorsolateral pre-frontal cortex.

Meditation and the brain

Recent brain-imaging and EEG studies have shown that areas in the frontal lobe of the brain associated with working memory and focused attention, especially the dorsolateral prefrontal cortex and the anterior cingulate, are activated during meditation . [For example,] Newberg et al. (2001) found increased activation in the dorsolateral and orbital prefrontal cortices, anterior cingulate cortex, and the sensorimotor cortices of the brains of eight meditating subjects. [Moreover,] Carter et al. (2005) found that Tibetan monks experienced at one-point meditation (a type that involves focused attention on a single object) were able to exert conscious control over a typically automatic phenomenon of attention, binocular rivalry.

This accumulating body of research indicates that meditation produces long-term changes in those areas of the brain involved in attention and working memory. These areas are critical for the enhancement of working memory capacity. This enhancement may have given Homo sapiens a competitive edge over other hominins and produced the emergence of symbolism about 50,000 bp. However, it can rightly be pointed out that it seems quite unlikely that our ancestors of 100,000 years ago or more were engaging in one-point or compassionate meditation. While true, numerous other studies have shown that far more mundane memory and attention tasks also activate the same brain areas.

Numerous other studies with similarly simple cognitive demands have indicated the dorsolateral prefrontal cortex to be an important high-level filter of attention, sustaining cognitive energy on relevant information while suppressing the processing of and responding to irrelevant signals.

Campfire rituals practiced by our hominin ancestors need not have been as disciplined as those of Tibetan monks to have activated the brain regions important for attention and memory. However, they were probably more intensive than the tests used in typical neuroscience studies. Those most susceptible to the rituals’ physical and psychological healing effects reaped the greatest survival and reproductive advantage — a Baldwinian process. Finally, there is evidence to suggest that these conditions were unique to Homo sapiens and not a regular part of the social worlds of Neanderthals and other archaic hominins.


5. Hypnotizability, or the ability to achieve a ritually-induced, health-enhancing, suggestibility-prone conscious state, is individually variable and heritable; and would have been fitness-enhancing in our ancestral past.

Shamanistic healing rituals

Strictly speaking, shamanism is a practice confined to cultures of the higher latitudes of Eurasia where the term originated. More broadly, however, the shaman is anyone who uses consciousness-altering ritual as a means of connecting with the spiritual world for the purpose of individual or community healing.

There is considerable evidence that shamanism (broadly defined) is humanity’s oldest form of religion. It is found in nearly all traditional societies. An increasing number of scholars agree that some of the Upper Palaeolithic cave art and artifacts reflect shamanistic rituals and, or, experiences . If so, they also suggest that shamanism pre-dates the Upper Palaeolithic, since the depiction reflects an already present system.

McClenon (1997; 2002) has marshalled considerable evidence indicating that those of our ancestors who were most susceptible to the beneficial physical and psychological effects of shamanistic rituals had a selective advantage over others in surviving illness or injury, overcoming debilitating emotional states and enduring the rigours of childbirth. Ritual healing is often highly effective for a range of maladies where psychological factors are involved, such as chronic pain, burns, bleeding, headaches, skin disorders, gastrointestinal disorders, and the discomforts and complications of childbirth .

Furthermore, only minimal verbal expression is required (if any at all) to add to the persuasive impact of the ritual (‘relax’, ‘heal’ etc.). Indeed, part of the power of spiritual healing is that it is something beyond words and logic. What is required for spiritual healing appears to be well within the behavioural and cognitive repertoire of our hominin ancestors: a belief in a healing spiritual power accessible through conscious-ness-altering ritual.

More than likely, it was the immediate positive psychological (ecstatic emotions/social bonding) and physical (placebo benefits, ‘miracles’) effects of these rituals that provided the motivation for enactment. What is critical is that these rituals required focused attention which activated those areas of the brain associated with attention and working memory.


What made humans different?

These rituals may have been one of the few activities that consistently differentiated Homo sapiens from other contemporary hominins.

When Homo sapiens moved into Europe around 40,000 bp, it was for good. Neither Neanderthals nor cold conditions stopped them from laying claim to the entire continent. Whatever it was that changed them did not similarly affect Neanderthals. So what was the difference?

The evidence suggests that a capacity for symbolism was present in some nascent or measured form in Neanderthals and, under certain environmental conditions (such as close contact with Cro-Magnons), this capacity flowered; but apparently those conditions were not a regular aspect of the Neanderthal world prior to the Upper Palaeolithic. This again emphasizes the fact that something was different about the Homo sapiens world, something generally not present in that of other hominins.


Why Neanderthals did not meditate

If the critical difference between Homo sapiens and other hominins was campfire rituals of focused attention, then why did Neanderthals not engage in this activity? Were they and other archaic hominins not just as likely to have been singing, chanting and encountering healing spirits around their campfires? Odd as it may seem, the answer to this seems to be no. Evidence suggests that Neanderthals had neither the time nor the energy to engage in such activities. They lived hard lives— harder, apparently, than Cro-Magnons’.

They did not invest as much as Cro-Magnons in home bases and the activities associated with them, including (and especially) communal ones involving a central fire.



Intensified or altered states are characterized by increasingly non-rational processing and internally-directed focus ranging from fantasy to hypnagogic imagery to sensory hallucinations.


Tuesday, January 5, 2010

Out-of-Body Experiences as the Origin of the Concept of a "Soul" Part Two - Thomas Metzinger

This is Part 2 of a two-part post extracting Metzinger’s article. Part 1 characterizes out of body experiences and explores their relationship to the experience of self. In the passages in this post, Meztinger places out of body experiences in a historical context, considers their scientific explanation, and examines their relationship to dualism. Like Pim Van Lommel’s article on near-death experiences we extracted below, Metzinger's article considers an unusual phenomenon within a scientific framework that is rigorous but at the same time open.

What is the “proto-concept of mind”? In many cultures we simultaneously find prescientific theories about a “breath of life”, e.g., the Hebrew ruach, the Arabic ruh, the Latin spiritus, the Greek pneuma or the Indian prana and the five koshas, respectively, etc. (for historical details and further references see Verbeke 1974, Schrott 1974). Typically this is a spatially extended entity, keeping the body alive and leaving it during phases of unconsciousness and after death. It has a material aspect, though more subtle than that of the physical body. (58)

The Western history of the concept of mind can be read as a history of a continuous differentiation of a traditionalistic, mythical, sensory proto-theory of mind which gradually led to a more and more abstract principle. Finally, culminating in Hegel, mind is conceived as devoid of all spatial and temporal properties. (57)

… In non-scientific contexts, we all know what we mean by a “soul”: Our soul is the innermost and essential part of ourselves; it is the prime candidate for the “true self”; it is the phenomenal locus of identity; it bears a deep relation to the emotional layers of our self-model, to the emotional core of our personality. For many of us it is something of which we secretly hope that it may survive physical death, because it is not identical to our body. (58)

...There is a well-known class of phenomenal states in which the experiencing person undergoes the untranscendable and highly realistic conscious experience of leaving his or her physical body, usually in the form of an ethereal double, and moving outside of it. (59)

These states correspond to a class (or at least a strong cluster) of intimately related phenomenal models of reality characterized by a visual representation of one’s own body from a perceptually impossible, externalized third-person perspective (e.g., lying on a bed or the road below oneself) plus a second representation of one’s own body, typically (but not in all cases) freely hovering above or floating in space. This second body-model is the locus of the phenomenal self. It forms the “true” focus of one’s phenomenal experience and also functions as an integrated representation of all kinesthetic qualia and all non-visual forms of proprioception. Such experiences are called out-of-body-experiences or OBEs…(59)

It is not at all inconceivable that there are physically or emotionally stressful situations, in which an information-processing system is forced to introduce a “representational division of labor” by distributing different representational functions into two or more distinct self-models (in what was previously called “multiple personality disorder”, see Metzinger 2003a, section 7.2.4). The OBE may be an instance of transient functional modularization, of a purposeful separation of levels of representational content in the PSM. (69)

For instance, if cut off from somatosensory input, or if flooded with stressful signals and information threatening the overall integrity of the self-model as such, it may be advantageous to integrate the ongoing conscious representation of higher cognitive functions like attention, conceptual thought and volitional selection processes into a separate model of the self. This may allow for a high degree of integrated processing, that is, for “mental clarity,” by functionally encapsulating and thereby modularizing different functions like proprioception or attention and cognition in order to preserve at least some of these functions in a life-threatening situation. Almost all necessary system-related information is still globally available, and higher-order processes like attention and cognition can still operate on it as it is presented in an integrated manner. (69)

Blackmore, … explicitly operating under the information-processing approach and analyzing the representational needs and resources of persons undergoing OBEs,… arrives at a theory describing OBEs as episodic models of reality, constructed by brains cut off from sensory input during stressful situations and having to fall back to internal sources of information. For instance, she draws attention to the remarkable fact that visual cognitive maps reconstructed from memory are organized from a bird’s eye perspective in the majority of subjects. She also points out an important phenomenological feature of intended bodily motion in the OBE-state: frequently, the way in which OBE subjects move around in the currently active model of reality is not smooth, as in walking or flying, but occurs in discrete jumps from one salient point in the cognitive map to the next. Blackmore’s observation emphasizes that, whatever else OBEs are, they certainly are internally simulated behavioral spaces. This phenomenological observation indicates that frequently these behavioral spaces, typically simulated by a brain under great stress, are spatially underdetermined – i.e., they are coarse-grained internal simulations of landmarks and salient spots in certain perceptual scenes that were seen and acted upon at an earlier stage in life. (72)

However, taking a more careful look at abstract, non-spatial aspects of the phenomenal self in these states, one discovers how it is not completely empty. An attentional and cognitive subject engaging in selective processing is modeled, and actually in existence: OBE subjects generally have good control over their attentional and their thought processes as such, even if almost all the contents of these processes may be hallucinatory. (73)

Let me point to a logical possibility, which is rarely noticed: OBEs may, at the same time, be both confabulatory states or complex hallucinations and information-bearing states correctly representing certain aspects of the environment. (78)

… OBEs show that self-models are not necessarily subject-models: You can represent something as your own body, without representing it as an agent with which you are identical, and you can do so under a perceptual model of the subject-object-relation. OBEs are like a “perceptualized” variant of reflexive self-consciousness. OBEs constitute a strong argument for the thesis that, while an accompanying bodily self-model may be fully “confabulated” by subpersonal mechanisms fighting for global coherence, the phenomenal locus of the self is always where the locus of cognitive and attentional agency is (see section 3.1). Interestingly, this is not true of bodily agency (recall the example of the marathon runner above). It is easy to conceive of systems that are not cognitive, but only attentional agents (for instance, animals) and nevertheless have OBEs. Therefore, the experience of attentional agency may be the core of phenomenal selfhood and perspectivalness and the origin of all consciously experienced intentionality. (77)

… It is as if, in situations where the self-model can no longer be anchored in internal somatosensory input or a low-level egocentric frame of reference (see Metzinger 2003a, section 5.4), higher cognitive functions like attentional processing or categorical thought simply take over in centering the global model of reality. In this way some persons undergoing an OBE truly are disembodied, thinking selves in a neurophenomenologically reduced version of the original Cartesian sense. However, it is not subjectively available to them that all this is just a model of reality generated by their central nervous system. (77)

…Even if a reductive explanation of all types of OBEs as deviant configurations of the human PSM should be achieved in the future, and even if the hypothesis about the history of the concept of a soul presented here is correct, it still remains logically possible that souls do exist. We would then not need the concept of a soul any more for the purposes of science or philosophy, because it would not play an explanatory role in any rational, data-driven theory any more. We would also have a deeper understanding of its genesis in human culture. But from a strictly logical point of view it remains possible that one day we discover a sense in which it is not an empty concept at all. (76)

This again leads to a number of issues of a more general philosophical interest. For anyone who actually had that type of experience it is almost impossible not to become an ontological dualist afterwards. In all their realism, cognitive clarity and general coherence, these phenomenal experiences almost inevitably lead the experiencing subject to conclude that conscious experience can, as a matter of fact, take place independently of the brain and the body: what is phenomenally possible in such a clear and vivid manner must also be metaphysically possible or actually the case. Although many OBE reports are certainly colored by the interpretational schemes offered by the metaphysical ideologies available to experiencing subjects in their time and culture, the experiences as such must be taken seriously. Although their conceptual and ontological interpretations are often seriously misguided, the truthfulness of centuries of reports about ecstatic states, soul-travel and second bodies as such can hardly be doubted. (78)

In conclusion, first-person reports about OBEs are available in abundance not only from all times, but also from many different cultures. There is a culturally invariant core to the phenomenon which obviously forms a coherent cluster of properties. The experience of a soul-like entity, an ethereal or astral body leaving the physical body during sleep, after accidents and in death can be called a “phenomenological archetype” of mankind. (79)

The functional core of this kind of phenomenal state is formed by a culturally invariant neuropsychological potential common to all human beings. Under certain conditions, the brains of all human beings, through specific properties of their functional and representational architecture, which have yet to be empirically investigated, allow for this set of phenomenal models of reality. (79)

Phenomenal states such as OBEs, which indicate a commonality in the neurofunctional architecture underlying the process of conscious human self-modeling, are the historical root of the proto-concept of mind. The proto-concept of mind eventually developed into Cartesian dualism and idealistic theories of consciousness. In short, the particular phenomenal content of OBEs led human beings to believe in a soul.(Let us simply call this the “soul-hypothesis.”…Given the epistemic resources of early mankind, it was a highly rational belief to assume the possibility of disembodied existence. And it was the PSM of homo sapiens which made this step possible.) (79)

The history of the concept of mind is a history of increasing differentiation and abstractness. Initially there was a theory of something concrete, an ethereal and spatially extended double, a breath of life. Eventually we find something entirely unworldly, an abstract, ideal principle. It is remarkable how the best theories of mind available today again turn it into a concrete process, fully endowed with temporal and spatial properties. However, in the light of contemporary cognitive neuroscience it is even more remarkable how, at the beginning of human theorizing about mind and consciousness, we find a very similar basic motive across very different cultural contexts: the idea of a “subtle body” which is independent of the physical body and the true carrier of higher mental functions like attention and cognition (Mead 1919). (80-81)

Taken as an ontological metaphor, the phenomenology of OBEs inevitably leads to dualism, and to the concrete idea of an invisible, weightless, but spatially extended second body. This, then, may actually be the folk-phenomenological ancestor of the soul, and of the philosophical proto-concept of mind: The soul is the OBE-PSM. (81)

Centuries of phenomenological reports describing it as a subtle body pointed in the right direction, and now we begin to see how it actually is a purely informational structure modeling bodily self-experience in cases of absent or disintegrated somatosensory/vestibular input. (81)

Out-of-Body Experiences as the Origin of the Concept of a "Soul" Part One - Thomas Metzinger

Philosopher Thomas Metzinger argues that out of body experiences are “the proto-concept of mind;…they are what led human beings to believe in a soul.” We have extracted his essay, originally published in the journal Mind and Matter in 2005, into two consecutive posts. This the first characterizes out of body experiences and explores their implications with respect to the experience of self. We have rearranged some of the material to fit our two post format. The numbers in parenthesis correspond to the page numbers in article. Metzinger is the head of the Theoretical Philosophy Group at Johannes Gutenberg University in Mainz Germany. His most recent book is The Ego Tunnel. (Reprinted with permission)


The bus to the train station had already been late. And now you have even queued up in a line at the wrong ticket counter! Nevertheless you manage to reach your train just in time, finding an empty compartment and, completely exhausted, drop into the seat. In a slightly unfocused and detached state of mind you are now observing the passengers sitting in the train on the other side of the platform. Suddenly you feel how your own train starts to move, very slowly at first, but accompanied by a continuous acceleration, which you can feel in your own body. Two or three seconds later, with the same degree of suddenness, your bodily sensation disappears and you become aware that it actually is the other train, which has now started to slowly leave the train station (see also Metzinger 1993, p. 185f). (65)

Such an experience is a very rudimentary form of an OBE, a hallucinated bodily self. The center of your global model of reality was briefly filled by a kinesthetic and proprioceptive hallucination, a non-veridical model of the weight and acceleration of your body, erroneously activated by your brain. The dominating visual model of your environment, largely formed by the input offered through the “picture frame“ of the train window, was underdetermined. In the special input configuration driving your visual system it allowed for two coherent interpretations: either it is the other train, or it is the train in which you are sitting, which has just started to move. The visual model of reality allowed for two equally consistent interpretations. At the same time there was a state of general physical and emotional arousal, accompanied by an unconscious state of expectancy about what is very likely going to happen next, and very soon. (61-62)

The information-processing system, which you are, selected one of the two possible interpretations in accordance with constraints imposed by a preexisting internal context and, as a system that always tries to maximize overall coherence, “decided” to simultaneously activate a suitable self-model, one that can be integrated into the new phenomenal model of the world without causing any major problems. Unfortunately, the chosen model of the world was wrong… A possibility was depicted as a reality. (61-62)

They frequently occur during extreme sports, for instance in high-altitude climbers or marathon runners (Alvarado 2000, p. 184):

A Scottish woman wrote that, when she was 32 years old, she had an OBE while training for a marathon. “After running approximately 12–13 miles . . . I started to feel as if I wasn’t looking through my eyes but from somewhere else. . . . I felt as if something was leaving my body, and although I was still running along looking at the scenery, I was looking at myself running as well. My ‘soul’ or whatever, was floating somewhere above my body high enough up to see the tops of the trees and the small hills.” (65)

They also frequently occur during sleep.

The process of detachment started at the fingertips, in a way that could be clearly felt, almost with a perceptible sound, a kind of crackling. It was precisely the movement which I actually intended to carryout with my physical hands. With this movement, I detached from my body and floated out of it with the head leading. I gained an upright position, as if I was now almost weightless. Nevertheless I had a body consisting of real limbs. You have certainly seen how elegantly a jellyfish moves through the water. I could now move around with the same ease. I lay down horizontally in the air and floated across the bed, like a swimmer, who has pushed himself from the edge of a swimming pool. A delightful feeling of liberation arose within me. But soon I was seized by the ancient fear common to all living creatures, the fear of losing my physical body. It sufficed to drive me back into my body.(64)

A 29-year-old woman has had absence seizures since the age of 12 years. The seizures occur five times a week without warning. They consist of a blank stare and brief interruption of ongoing behavior, sometimes with blinking. She had an autoscopic experience at age 19 years during the only generalized tonoclonic seizure she has ever had. While working in a department store she suddenly fell, and she said, “... the next thing I knew I was floating just below the ceiling. I could see myself lying there. I wasn’t scared; it was too interesting. I saw myself jerking and overheard my boss telling someone to ‘punch the timecard out’ and that she was going with me to the hospital. Next thing, I was in space and could see Earth. I felt a hand on my left shoulder, and when I went to turn around, I couldn’t. Then I looked down and I had no legs; I just saw stars. I stayed there for a while until some inner voice told me to go back to the body. I didn’t want to go because it was gorgeous up there, it was warm – not like heat, but security. Next thing, I woke up in the emergency room.” No abnormalities were found on the neurological examination. Skull CT scan was normal. The EEG demonstrated generalized bursts of 3/s spike-and-wave discharges. (66)

The prevalence of OBEs ranges from 10% in the general population to 25% in students, with extremely high incidences in particular subpopulations like, to take just one example, 42% in schizophrenics (Blackmore 1986; for an overview and further references see Alvarado 1986, 2000, p. 18p, and Irwin 1985, p. 174p). However, it would be false to assume that OBEs typically occur in people suffering from severe psychiatric disorders or neurological deficits. Quite the contrary, most OBE-reports come from ordinary people in everyday life situations. (64)

At present it is not clear whether the concept of an OBE possesses one clearly delineated set of necessary and sufficient conditions. The concept of an OBE may in the future turn out to be a cluster concept constituted by a whole range of diverging (possibly overlapping) subsets of phenomenological constraints, each forming a set of sufficient, but not necessary, conditions. On the other hand the OBE clearly is something like a phenomenological prototype. There is a core to the phenomenon, as can be seen from the simple fact that many readers will have already heard about in one way or another. (59)

One can offer a representationalist analysis of OBEs by introducing the concept of a “phenomenal self-model” (PSM; for more on the concept of a PSM, see Metzinger 2003a). APSM is an integrated, conscious representation of the organism as a whole, including not only its spatial features, but also those of its own psychological properties to which it has access. An important feature of the human PSM is that it is almost entirely transparent. This means that we, as the organisms activating the PSM in their own central nervous system, cannot recognize it as a model: We become naive realists with regard to its content, the transparent representational content of the PSM is simply what we experience and later refer to as “our” conscious self. (59-60)

Given this conceptual background, we can analyze OBEs a class of deviant self-models. On the level of conscious self-representation a prototypical feature of this class of deviant phenomenal self-models seems to be the coexistence of (a) a more or less vertical representation of the bodily self, from an external visual perspective, which does not function as the center of the global model of reality, and (b) a second self-model, which according to subjective experience largely integrates proprioceptive perceptions – although, interestingly, weight sensations only to a lesser degree – and which possesses special properties of shape and form that may or may not be veridical. Both models of the experiencing system are located within the same spatial frame of reference (this is why they are out-of -body-experiences). (60)

…You see your own body, and you recognize it as your own, but presently it is not the body as subject, the body as the locus of knowledge and of lived, conscious experience. (67) OBEs, phenomenologically, are not states of disembodiment. On the contrary, there always seems to be a spatially located phenomenal self, even if its embodiment is reduced to a pure spatial point of visuo-attentional agency. (68) In general it seems safe to say that prototypical OBEs are fully transparent states. The model of reality generated during the experience is not experienced as a model, although in experienced subjects and practitioners this fact may well be cognitively available during the episode. It is precisely the transparency of OBEs, which has led generations of experiencers and theoreticians in many cultures and for many centuries in the past to naive-realistic interpretations of this deviant form of phenomenal self-modeling. However, many OBE subjects also report a “dreamlike quality, as if being awake in a dream”. (68)

The physical body viewed from an external perspective is very rarely distorted or changed in shape and size. However, the subject component of the intentionality-relation modeled in these states may vary greatly (note how just the opposite principle holds for ordinary waking states). Some OBE subjects see or feel themselves in a weightless replica of their original body, others experience themselves as being in no body at all or in a kind of indeterminate form, such as a ball of light or an energy pattern (Alvarado 1997, p. 18; Green 1968) or even as “pure consciousness” (Alvarado 2000, p. 186). (70)

This may indicate that spatial content is not strictly necessary in realizing the function fulfilled by the second self-model for the system as a whole. In other words, those higher functions such as attention, cognition and agency, which are integrated by the “dissociated” self, now are only weakly embodied functions. In order to be carried out they do not need the integration into a spatially characterized, explicit body image. Arguably, attentional and cognitive agency can functionally be decoupled from the process of autonomic self-regulation and the spatial self-representation necessary for generating motor behavior. Conceptually, this is an important insight about the human mind. As it is plausible to assume that also non-cognitive creatures like animals could undergo the type of fully disembodied OBEs described above, we may conclude that attentional agency actually is one of the essential core properties underlying the conscious experience of selfhood. Spatial self-representation and cognitive self-reference are not necessary for selfhood. (70)