God, Dopamine, and 3-Dimensional Space
The Ingenious Theories of Fred Previc
What are god and heaven doing up in the clouds?
Space. The final frontier. And when it comes to religiosity, it just might be. Out of the clouds, Fred Previc has constructed an ingenious theory of religiosity based on the multiple mechanisms employed by the brain to map and direct its behaviors in 3-dimensional space. As we shall see, Previc's theory of religiosity has many similarities with Brack's hemisphericity theory of political orientation, both of which propose a key role to the dopaminergic system in the modulation of religiosity (and in our case, political conservatism).
Although our theories were derived independently, Previc's original manuscript, The role of extrapersonal brain systems in religious activity, predates the introduction of our theory (via the web) by several months. Although it does not specifically address political disposition, it is such a theory by proxy, via the strong relationship between religiosity and political conservatism. While Previc's theory makes full use of the large volume of literature implicating the dopamine system in religious behavior, it is a quantum leap in the theory of religiosity, and centered upon the various mechanisms on how the brain behaves in the four 3-dimensional spatial realms it has constructed for itself, and how time itself has become enmeshed with the brain's rendering of space.
Fred Previc knows something about space. Previc was the lead of the United States Air Force's Spatial Disorientation Countermeasures Task Group, which studied pilot spatial disorientation in flight, a major cause of aeronautic accidents. How he has subsequently woven his research and theories on the brain's rendering of space into a theory of religiosity is one the great insights in the history of neuropsychology. But what exactly is Previc's theory?
Previc's Four Realms of 3-Dimensional Space
While we take the existence of 3-dimensional space for granted, things are not so simple in the brain. This is seen in lesion studies, where certain regions of the brain have a very specialized function in handling the space around us. Let's take a look at hemineglect, which is typically associated with damage to the right posterior parietal cortex.
A patient with hemineglect was asked to redraw
the pictures on the left.
As can be seen above, patients with the curious condition of hemineglect are missing half of space, and even worse, often aren't aware that it is missing. How does one walk around not noticing half of space is missing? Further, these patients, when presented with a plate of food, will often only eat the food on half of the plate.
The piecing together of the data from numerous lesion studies and visual experiments led to a break down in the conventional view that the brain constructs a single view of space. Rather, it seems to construct more specific versions of space that optimize the simultaneous execution of various categories of behaviors. And according to Previc, it has constructed four spatial realms: the peripersonal (PrP); the ambient extrapersonal (AeP) ; the focal extrapersonal (FcE); and the action extrapersonal (AcE). (See Previc's The Neuropsychology of 3-D Space, 1998, Psychological Bulletin, Vol 124.)
Previc's four realms of space are depicted in the diagram below (excerpted from Fred Previc's The role of extrapersonal brain systems in religious activity, 2006, Conciousness and Cognition 15).
Diagram 1: Previc's Four Spatial Realms
Peripersonal Space: a Liberal Connection?
The yellow field in the above diagram represents the well-known concept of peripersonal (PrP) space, which is the space within our grasp. The neurology surrounding peripersonal space is interesting, as it supports the control of the upper limbs. In primates, these limbs are positioned in the lower visual field. There is a distinctive downward bias of the peripersonal visual field, as can be easily be seen in the disproportionate time we spend manipulating objects that are beneath eye level.
The peripersonal system also has a distinctive neuroanatomy and neurochemistry, one that runs right into our theory of political orientation. Previc describes the neuroanatomy of the peripersonal system as "mainly housed in the dorsal cortical networks extending from the dorsal visual pathways through the lateral and medial portions of the parietal lobe and finally into the superior-lateral portions of the frontal lobe".
Interestingly, the right hemisphere has a greater role in the management of the peripersonal system. The PrP system is also associated with the greater role of both noradrenaline and serotonin in its neurochemical management. Noradrenaline and serotonin are distributed asymmetrically in the right hemisphere, and the regular readers of this web site will immediately see the connection to political-religious disposition.
We have previously proposed an elevated influence of the right hemisphere and both the noradrenergic and serotonergic systems in liberal cognitive styles and behavior. Does this mean that liberalism is more oriented towards the peripersonal system than conservatism? This is probable. But this isn't the only space that seems to be favored by liberals, as we also suspect a stronger orientation towards ambient extrapersonal space.
Ambient Extrapersonal Space: where the liberals are?
Extrapersonal space is the area outside our immediate grasp, and as organisms increase in complexity, they devote proportionately more neurology to its analysis. In Previc's theory, there are three functional realms of extrapersonal space.
Previc's ambient extrapersonal space (AmE), depicted as the green field in diagram 1, is essentially the brain's version of gravitational space, which supports the orientation and posture of the body in the earth's gravitational field. As such, it is largely responsible for the movement of the lower limbs. Previc's AmE space starts where PrP space ends, about 2 meters from the body, and "extends to the outermost boundaries of the visual field" that "lie outside our frame of motion".
Driving an automobile provides an excellent example, as maintaining velocity and lanekeeping are predominately the function of AmE space. AmE functionality also includes the stabilization of the perceptual world, allowing the other visual systems to function more efficiently. And like peripersonal space, there is a downward bias towards the lower visual field.
While the sense of vision predominates in the AmE realm, both vestibular (balance) and proprioceptive (body position) inputs complement visual inputs. Interestingly, vestibular and proprioceptive inputs also participate in the functioning of the PrP system. The AmE system is not very concerned about details, as "spatial orientation can easily be maintained despite considerable optical degradation".
The AmE system employs dorsal visual pathways that course through the parietal lobe, and has a distinctive neurochemistry dependent on noradenergic and serotonergic transmission. This links it to its sister spatial system, the PrP, and further, links it to liberal political-religious orientations via the elevated adaptation of noradrenaline, serotonin, and the right hemisphere. Are the nonreligious liberals more oriented towards peripersonal and ambient extrapersonal space than the religious conservatives? Based on Previc's theories, this is highly probable. But first, where do god and the conservatives live?
Focal Extrapersonal Space
When it comes to god, the real action of Previc's religious theories start with the action extrapersonal system and its close cousin, the focal extrapersonal system (FcE). The FcE just happens to be the only spatial system associated with retinotopic coordinates. Retinotopy is the mapping of locations in the visual field onto the cortical surface of the brain. As such, the focal extrapersonal system is the most limited in scope (see the red area in diagram 1), but the most important in visual search, and the critical functions of object and facial recognition.
As opposed to the dorsal orientation of the PrP and AmE systems, the FcE system runs "ventrally through the occipital-temporal pathways and finally on into the lateral and medial-basal portions of the frontal lobe". The FcE is dominated by visual inputs confined to the central 30 degrees of the visual field. The FcE is directed towards distant space, but can focus on objects within peripersonal space as well.
Unlike the downward bias of the PrP and AmE systems, the FcE has a strong bias towards the upper visual field. The FcE system is where motion, local form, and depth processing prevail. But what makes the FcE system particularly relevant to political-religious disposition is its reliance on dopaminergic transmission. In fact, key dopaminergic pathways of the FcE system run right through the inferior temporal lobe--a key region implicated in religious disposition and political conservatism.
Action Extrapersonal Space
Previc's action extrapersonal space, AcE, "uses mainly visual and auditory information to enable us to orient, navigate, and interact in topographical space". It also orients to targets, and is "closely involved with episodic memory for places and events". AcE integrates visual, auditory, proprioceptive, and vestibular inputs "concerning the movement of the head in space", and shares common temporal-occipital neural substrates with the FcE, along with coursing through the politically-hot orbitofrontal cortex.
Like its sister system, the FcE, the AcE system is biased toward the upper visual field. "Attentional neglect of upper, distant space is a frequent sequel to inferior temporal lobe damage". As previously noted, there is a strong relationship between the temporal lobe and religious disposition. According to Previc's theory, it is the action extrapersonal system that is most closely linked with religiosity.
Unlike the retinotopic coordinate system utilized by the FcE, AcE space is gaze-centered, dependent on the position of the head in space. Neurons in the hippocampus are activated by the space upon which gaze is directed. AcE space is interesting in that it completely maps a 360 degree surround, using auditory cues to handle the space behind the head. The AcE system extends from the outer boundary of peripersonal space, about 2 meters, to about 30 meters.
And like the FcE system, dopaminergic neurotransmission prevails in the AcE. In fact, Previc has not only constructed a theory of the dopaminergic origins of religiosity, he has also constructed a theory linking dopamine with human evolution. And all this from studying the way the brain maps space.
God and the DRD4 Gene
According to Previc, the action extrapersonal system is the most closely aligned to religiosity. In Previc's abstract, he states "the ventral dopaminergic pathways involved in religious behavior most closely align with the action-extrapersonal system in the model of 3-D perceptual motor interactions....These pathways are biased toward distant (especially upper) space and also mediate related extrapersonally dominated brain functions such as dreaming and hallucinations".
"Hyperreligiosity is a major feature of mania, obsessive-compulsive disorder, schizophrenia, temporal-lobe epilepsy and related disorders, in which the ventromedial dopaminergic systems are highly activated and exaggerated attentional or goal-directed behavior toward extrapersonal space occurs....the evolution of religion is linked to an expansion of dopaminergic systems in humans, brought about by changes in diet and other psychological influences."
Previc cites a genetic study regarding dopamine and religion: "it is consistent with the finding...that 'spiritual acceptance' is by far the most highly correlated (p < .001) personality trait with the number of repeat alleles of the dopamine D4 receptor gene (DRD4)". The higher reproductive output of the religious may indeed be advancing the occurrence of the DRD4 gene in the human gene pool.
The Stargazer Rat: hyper-dopaminergic activity has moved this rat's
field of vision towards upper space
(Adapted from Previc, 1998)
Religion, to Previc, "represents the extension of distant extrapersonal space and time into abstract and cosmic realms---e.g., heaven and eternity---even as it relies on mammalian brain pathways that ordinarily oversee whole-body, head- and oculomotor orienting and exploration in the distal portions of actual 3-D space".
Dopamine, Extrapersonal Space, Religious Hallucinations, and Near-Death Experiences
Previc reviews a lot of evidence pertaining to the dopamine connection with religiosity. As seen above with the stargazer rat, dopamine stimulates a "variety of upward-directed movements, including vertical rearing, climbing, jumping, and upward head and eye movements". Conversely, upper visual field neglect occurs with damage to the substantia nigra dopamine pathways.
The proposal that hallucinations and dreams have inspired the foundation of major religions (St. Paul, Mohammed, and Joseph Smith) ties in well with Previc's extrapersonal space. "Dreams and hallucinations represent the triumph of the extrapersonal systems over the body-oriented or peripersonal systems".
Previc goes on to state that hallucinations and dreams are associated with "extrapersonal space (out-of-body experiences, distant scenes, etc.), little reaching, consummatory, tactile or other peripersonal experiences, and a preponderance of upward eye movements". People usually don't dream or hallucinate about eating, drinking, or feeling things, which are all associated with the peripersonal system.
Mohammed's vision of the star in the dark side of the moon.
A dopaminergic hallucination?
St. Paul reported a light shining down from heaven, Joseph Smith reported a light shining directly overhead, and Mohammed's vision of the crescent and star were all upper visual field events, and all in action extrapersonal space. Out-of-body hallucinations, which often accompany near-death episodes, originate from the brain's construction of extrapersonal space. 100% of all dreams contain visual imagery, 65% contain auditory sensations, and only 1-2% contain tactile sensations.
Corroborating the relationship between Previc's action extrapersonal space and near-death out-of-body experiences, increased dopaminergic transmission occurs during hypoxia. Previc noted that "out-of-body hallucinations are particularly likely to involve the activation of the left hemisphere...and to appear predominately in the right visual field".
Dreaming is the domain of the extrapersonal systems and the upper visual field. There is a preponderance of upward eye movements during REM sleep, highlighting the relationship between dreaming and the upper space. Based on fMRI studies of REM sleep, Previc concluded that "forebrain activation during dreaming most closely resembles that of the action-extrapersonal pathways".
Further, "dreaming relies mainly on dopaminergic and cholinergic systems located in the cerebral cortex. These are the major neurotransmitters in the ventromedially based 'action-extrapersonal' cortical network". Hallucinations tend to be of the auditory variety, however, visual hallucinations are most likely to occur with stimulation of the temporal lobe. Hallucinating schizophrenics activate the temporal lobe, along with the anterior cingulate and the dopamine-rich striatum. Remarkably, these regions have also been implicated in religious meditation and prayer.
Further, Previc noted that "lesions (i.e., under-activation) of the right hemisphere are almost twice as likely as left-sided ones to produce complex visual hallucinations...Similarly, epileptiform activity (i.e., overactivation) in the left hemisphere is almost twice as likely to produce hallucinations and delusions." "Drugs that simulate [dopamine], such as amphetamine and L-dopa, are hallucinogenic".
God, Heaven, and Upper Extrapersonal Space
"In the beginning..." Apollo 8's crew has a religious experience in outer space.
Across almost all religions, the good gods live in upper space, be it on top of a mountain, beyond the clouds, or on distant planets. This is not so much a property of the gods, rather, it is a property of how the brain organizes space. Previc writes "the religious significance of upper space is further reflected in upward oriented behaviors and orientations during individual religious experience and practice".
"Upward eye shifts...accompany meditation...upward eye deviations promote generation of EEG alpha rhythm characteristic of the initial meditative state...upward ocular deviations...occur in mystical states induced by magnetic stimulation of the brain." The relationship of religion "and distant, upper space may partly account for the religious experiences and conversions frequently found in pilots and astronauts while flying high above the ground."
The Confusion between Religiosity, Spirituality, and Hemisphericity
Previc reviews a lot of scientific literature pertaining to hemisphericity, religiosity, and spirituality, and notes a mild relationship between the left hemisphere and religiosity. We have proposed that religiosity is primarily the construct of the left hemisphere, and spirituality is primarily the construct of the right. This proposal is based on a substantial amount of cognitive evidence we have collected.
Those that classify themselves as spiritual, rather than religious, are actually the cognitive cousins of the agnostics and atheists. Unfortunately, the neuroimaging community generally perceives religiosity and spirituality as the same thing, which explains the contradictory findings pertaining to hemisphericity and religiosity. Previc's review highlights this problem, although Previc indeed does not make the distinction between the religious and spiritual.
While Previc cites a litany of studies implicating the left hemisphere in religiosity, he goes on to state "other behavioral studies have inferred greater right-hemispheric activity in clinically normal individuals disposed to magical ideation and paranormal beliefs". In other words, the spiritual indeed seem to exhibit a right hemispheric cognitive bias, although Previc lumps spirituality in with religiosity. Further, Previc goes on to say "the notion that mixed-handedness (i.e., reduced left-hemispheric dominance) is more likely to be associated with paranormal ideas...is somewhat contradicted by the finding that mixed-handers are less likely to believe in religious dogma such as Creationism".
Again, the fact that mixed-handers are more likely to hold paranormal beliefs and less likely to believe in Creationism is evidence for our theory that religiosity and spirituality are more likely to be associated with the left and right hemispheres, respectively. Will the neuroimaging community properly differentiate religiosity and spirituality in future experiments? To date, this has created substantial confusion in the interpretation of imaging results.
Religiosity and Mental Disorders: Who is crazier, Conservatives or Liberals?
Ever since the 1977 study of Frumkin and Ibrahim, which concluded that psychotics were more likely to be supporters of Ronald Reagan, the relationship between schizophrenia and political conservatism has been controversial. The more recent Christopher Lohse study, which purportedly found a similar relationship between George W. Bush supporters and psychosis (we have been unable to obtain a manuscript), is certainly plausible based on the relationship between hyper-dopaminergic activity, schizophrenia, the left hemisphere, and political conservatism.
Previc's review of religiosity and mental disorders also adds fuel to the fire of a schizophrenic-conservative link. Previc writes "psychotic delusions are a common feature of mania, [temporal lobe epileptic] psychosis, and paranoid schizophrenia...all of these disorders are to varying degrees associated with overactivity of the fronto-temporal pathways (mostly on the left side), elevated [dopamine], and a bias toward extrapersonal space".
Previc then goes on to make the connection between the above mental disorders and religiosity: "the limited evidence to date indicates that persons suffering from mania are much more likely than normals to profess a belief in major religious tenets....Religious delusions and hallucinations were reported by 90% of bipolar manic patients...manic patients were second only to schizophrenics in their religious experiences and ranked ...ahead of patients with seizure disorders, depression, personality disorders, and anxiety disorders".
Previc makes a mild case for a connection between OCD and religiosity: "there is undeniably at least a moderate relationship between OCD and religiosity, in that obsessive traits are much more common in highly religious persons". But his case for a schizophrenic connection to religiosity is much stronger: "schizophrenia, especially of the paranoid variety, is the clinical disorder most clearly linked to hyperreligiosity....Because schizophrenia additionally represents the disorder most closely aligned with extrapersonal space, it is arguably the most valuable disorder for understanding the relationship between religious activity and extrapersonal brain mechanisms".
Previc continues "as with schizophrenia in general, functional imaging studies point to a left-temporal predominance for delusions of a religious nature". Previc then discusses the well-known link between temporal lobe epilepsy and religiosity: "...TLE is associated with hyperreligiosity and further argued the hyperreligiosity was more likely to occur in left-sided TLE".
The evidence is certainly consistent with the elevated political conservatism-schizophrenic link noted in the Frumkin and Ibrahim study, and also (presumably) in the Lohse study. The conservatives seem to be more prone to mental disorders of the left hemisphere, while, based on the evidence we've gathered, liberals are more prone towards depression and anxiety disorders, which are predominately right hemispheric in origin. The mental disorder evidence supports both Brack's hemisphericity theory of political orientation and Previc's dopaminergic-spatial theory of religiosity.
Dopamine and the Evolution of Man
Previc's perspective on the world is a very wide one, starting from the inner reaches of peripersonal space and extending all the way to the evolution of the human brain. Previc has formally proposed a dopaminergic theory of human intellect: "the expansion [of the dopamine system] began early in primate evolution and produced a more homogenous distribution of DA throughout the brain, particularly in its upper layers...one reflection of the continued expansion of DA systems in humans is the large increase (near-doubling, relative to body-weight) of the DA-rich neostriatum of humans relative to chimpanzees, who spend the majority of their day in peripersonal activities".
Previc continues: "the final expansion of DA could have prompted the rise in abstract reasoning, human creativity in the form of art and music, and religious behavior....Both abstract reasoning and religious thought involve an emphasis on nonvisible (distant) space and time, and both are linked to the upper field....It might also seem strange that two ostensibly antagonistic processes--religious behavior and abstract (scientific) reasoning--may have co-evolved....both phenomena are concerned with abstract concepts and comprehensive frameworks with which to comprehend spatio-temporal events in the external environment".
The Previc, Persinger, and d'Aquili-Newberg Models of Religious Experience
Previc sums up his theory: "religious behavior...are largely a product of the extrapersonal brain systems that predominate in the ventromedial cortex and rely heavily on dopaminergic transmission. By contrast, systems dealing more with body-oriented space in parietal and other dorsal brain areas and predominately utilizing serotonergic and noradrenergic [note Brack's proposal, developed independently, that liberalistic behaviors correlate with the behaviors associated with the noradrenergic and serotonergic systems] circuits appear to be less activated during religious behavior. Like the extrapersonal systems and other phenomena mediated by them such as dreams and hallucinations, religion appears to be biased toward distant (upper) space and time".
First and foremost, Previc's theory explains some of the more ubiquitous characteristics of modern religions: the orientation of god, heaven, and other religious beliefs into upper, distant space. Previc's theory also accounts for the hallucinogenic nature of religious visions, the religious interpretations of near-death experiences, and the relationship between hyperreligiosity and mental disorders such as schizophrenia.
It also accounts for the tendency for religious behavior to induce emigration, which is the primary mechanism employed by animals to relieve the pressures of expanding populations. "Promised lands" are a recurrent religious theme, and could be interpreted in the Previc model as a stronger orientation towards distant space. The evolutionary value of an orientation towards distant space lies in the reproductive advantages associated with new lands and lower population density.
It also is a theory that encompasses both the Persinger and the d'Aquili-Newberg religious models. In other words, the Persinger temporal and d'Aquili-Newberg meditative models are a special case of the Previc dopaminergic-spatial model of religiosity. D'Aquili-Newberg's proposal of the "orientation-association" area is functionally and anatomically analogous to Previc's ambient extrapersonal space and peripersonal space.
D'Aquili-Newberg's "attention-association" area is functionally and anatomically analogous to Previc's action extrapersonal and focal extrapersonal space. While the dopaminergic system is central to both Previc's theory of religiosity and Brack's theory of political orientation, d'Aquili-Newberg and Persinger proffer no distinct role of dopamine in their respective theories. Previc's theories on how the brain constructs space are much more advanced than d'Aquili-Newberg and Persinger, which is to be expected, given Previc's specialty.
Previc discusses the work of Andrew Newberg and the late Eugene d'Aquili at length: "a review of the neuroanatomy and neurochemistry of dreaming, hallucinations, and religious beliefs, practices and experiences in normal humans indicates that there may be a common neural substrate of all behavioral phenomena that reflect a predominance of extrapersonal brain system activity and a reduction of bodily (self-oriented) activity (see also D'Aquili & Newberg, 1993)".
However, in Newberg's most recent book, Born to Believe, the work of Previc is never mentioned. Has the Machiavellian nature of scientific competitiveness raised its ugly head? The quiet Previc is a far cry from the headline-chasing component of the scientific community, but scientists, like the public in general, follow the same general rules of reproductive competition, which is unfortunately fought in pages of journals and books.
In our view, the Previc theory encapsulates and supersedes both the Persinger and d'Aquili-Newberg theories, and is the best current general model of religiosity. Unfortunately, like its predecessors, it does not distinguish between the strong cognitive and behavioral variations of those that describe themselves as religious, and those that describe themselves as spiritual.
White Conservatives in Outer Space
Finally, we must note some potential racial variations, on average, in the orientation towards Previc's four realms of space. It is certainly arguable that the northern European gene pool is responsible for man's initial incursion into outer space. Are the Caucasians more oriented towards action extrapersonal and focal extrapersonal space than the other races? Does this account for their greater propensity to spread out all over the planet--even into outer space?
Are the Asians, Hispanics, Indians, and Blacks more oriented towards peripersonal and ambient extrapersonal space? Does this explain the mystical nature of the eastern religions, such as Hinduism and Buddhism?
The white conservative tendency to explore space
Previc's peripersonal and ambient extrapersonal spatial realms match up hemispherically and neurochemically with our proposal that liberals are more likely to be oriented towards their right-hemisphere and their noradrenergic and serotonergic systems. Liberals may indeed be living in local peripersonal space, orienting this world with a watchful eye on the expansive horizon of ambient space.
Conversely, Previc's action extrapersonal and focal extrapersonal space match up well with our proposal of a left-hemispheric and dopaminergic orientation of political conservatism. The goal-seeking nature of political conservatism seems to be oriented towards targets in distant space. Indeed, this flavor of spatial orientation supports higher birth rates.
It is indeed an interesting fact that the first lunar explorers were predominately politically conservative. Coincidence? We don't think so.
Charles Brack, February 2008