Dopamine, and 3-Dimensional Space
Theories of Fred Previc
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,
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.
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?
Four Realms of 3-Dimensional Space
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.
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.
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.)
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
Space: a Liberal Connection?
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.
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".
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.
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.
Extrapersonal Space: where the liberals are?
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.
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".
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.
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
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
Focal Extrapersonal Space
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.
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.
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, 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
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.
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.
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.
and the DRD4 Gene
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".
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."
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)
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".
Extrapersonal Space, Religious Hallucinations, and Near-Death Experiences
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.
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
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?
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.
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".
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".
"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.
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".
Heaven, and Upper Extrapersonal Space
"In the beginning..." Apollo 8's crew has a religious experience
in outer space.
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".
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."
Confusion between Religiosity, Spirituality, and Hemisphericity
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.
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
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".
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?
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
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".
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".
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".
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".
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.
and the Evolution of Man
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".
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
Previc, Persinger, and d'Aquili-Newberg Models of Religious Experience
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".
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.
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.
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.
"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.
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,
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.
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.
Conservatives in Outer Space
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
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
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.
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.
is indeed an interesting fact that the first lunar explorers were predominately
politically conservative. Coincidence? We don't think so.