Considering that the brain is increasingly being credited with having a role in everything we think, feel, and do, it was probably just a matter of time before it was postulated that religious belief has a neural substrate.
Considering that the brain is increasingly being credited with having a role in everything we think, feel, and do, it was probably just a matter of time before it was postulated that religious belief has a neural substrate. The question of how the brain might be "hardwired" for spirituality has captured the interest of many investigators who have established careers in fields as different as neurology, theology, and neuroscience and spawned the new discipline of neurotheology.1Neurotheology, neurons, and neurotransmitters
Neurotheologians argue that the structure and function of the human brain predispose us to believe in God. They claim that the site of God's biological substrate is the limbic system deep within the brain, which has long been considered to be the biological center for emotion. Rhawn Joseph, a prominent neurotheologian, goes a step further to suggest that the limbic system is dotted with "God neurons" and "God neurotransmitters."2
Among the limbic structures that have been associated with religious belief, the most frequently credited are the hypothalamus, amygdala, and hippocampus. Neurotheologians point to changes in functional MRI scans in these areas as research subjects engage in religious meditation. They reason that if thinking about God changes the way the brain works, there must be some inherent neural imperative to believe in God in the first place. In making this connection, neurotheologians are following the lead of neuroscientists who claim that changes seen in functional brain scans in persons who are happy, depressed, or obsessed demonstrate that these phenomena are brain driven.
Ilia Delio, who is a member of the Roman Catholic Franciscan Order and holds doctoral degrees in pharmacology and historical theology, gives this account of how neurotheologians conflate theology and neuroscience to make the case for a religious neural substrate. "It is tempting to speculate that there is a 'God module' in the brain and that such a module is located in the area of the limbic system; however, such speculation needs to be made cautiously. What these findings do point to, however, is that spirituality involves the brain. For the first time in human history we are beginning to understand spiritual experience not as something apart from the physical human but rather bound up with human matter, that is, the matter of the brain. Thus, matter and spirit are no longer seen to be opposed but are indeed mutually related, if not one and the same."3
Challenging the idea that religious belief is rooted in any particular brain structure or function, David L. Smith, a Roman Catholic priest and clinical psychologist, asks: "If 'God neurons' or 'God neurotransmitters' actually exist in the brain, are they defective in the agnostic and absent in the atheist?"4 Implicitly, Smith is holding the neurotheologians to the same standard that neuroscientists would feel obligated to meet when proposing a connection between specific neurons and neurotransmitters and some behavioral phenomenon: these neurons and neurotransmitters must be shown to exist. No scientist or theologian has come forward to stake a clear-cut claim to "God neurons" and "God neurotransmitters." Smith concludes that neurotheology is "a pseudoscience cloaked in the mantle of Cartesian dualism."4
The following quote from an article published in Zygon, the official journal of neurotheology, typifies the kind of language and reasoning found in neurotheological texts. The authors are Eugene d'Aquili, MD (a psychiatrist) and Andrew Newberg, MD (a neurologist). "We must now turn to the normal functioning of 4 tertiary association areas and to their relation-ship to the limbic system. We postulate that these areas, under certain conditions, may be involved in the genesis of various mystical states, the sense of the divine, and the subjective experience of God."5
Meaning seems to be more toyed with than revealed here as language slips and slides. This is about as far as the arguments of the neurotheologians ever go, yet they proceed to their conclusions as if they have made their point.
God: The genetic imperative
Dean Hamer, PhD, a behavioral geneticist who has worked at the National Cancer Institute (NCI) and the NIH, took the neurotheologians' proposal that religious belief has a neural substrate another step and asked: Is God, in effect, embedded in our genes and, if so, which genes? If this were the case, it would mean that people are not only wired to believe in God but genetically programmed to do so as well.
Hamer's work is not about demonstrating the existence of God, which is the domain of religion, but about showing that spirituality is a real phenomenon that can be described and measured. Spirituality, as Hamer sees it, derives from genes, and religion from memes-the cultural counterpart of genes-ideas, values, or patterns of behavior that are passed from one generation to another nongenetically, often by imitation. Religion, he believes, is rooted in nurture and spirituality in nature.
In 2004, Hamer published The God Gene: How Faith Is Hardwired Into Our Genes,6 which was showcased in a Time cover story on neurotheology.7 Hamer made it clear that he had approached his work with the tools of natural science: "The first task for any scientist attempting to link genetics to spirituality is to show that spirituality can be defined and quantified." (This quote and subsequent quotes by Hamer are from The God Gene.)
But how does one quantify spirituality, a quality that would seem by its very nature to defy measurement? As part of a study on genetics and personality in cigarette smokers sponsored by the NCI,8 Hamer had previously used the Temperament and Character Inventory, which includes a self-transcendence scale developed by C. Robert Cloninger, MD,9 professor of psychiatry at Washington University Medical School in St Louis. Hamer felt that Cloninger's self-transcendence scale made it possible to quantify "people's capacity to reach out beyond themselves-to see everything in the world as part of one great totality."
Having found a way to measure self-transcendence, Hamer's next step was to identify candidate genes that might influence people to be spiritual. He started with the observation that certain drugs altered consciousness toward self-transcendence and mysticism. Psilocybin, a hallucinogen derived from mushrooms, is known to induce mystical and sometimes religious states.10 Certain amphetamines, including ecstasy (3,4-methylenedioxymethamphetamine, MDMA), have well-documented hallucinogenic and mind-expanding properties. Hamer asked: Is there some chemical in the brain that is structurally similar to these drugs and that could endogenously promote transcendent experience?
Mind-altering drugs are thought to work primarily through receptors that bind monoamine ligands in the brain. Hamer looked at factors that would generally influence monoamine function in the drug-free brain, especially in the serotonin, dopamine, and noradrenaline neurotransmitter systems. After several false starts, Hamer had a chance meeting with George Uhl, MD, PhD, a neurobiologist at the National Institute of Drug Abuse, who studies generic vulnerability to substance abuse. Uhl had found some new variants in a gene called vesicular monoamine transporter 2 (VMAT2). This gene makes a protein for the vesicles that package neurotransmitters in the presynaptic neuron and later release these signaling chemicals into the neuronal synapse. He had sequenced the gene and mapped out a number of variants, including the polymorphism A33050C, located on chromosome 10. (In position 33050 of that chromosome, a person may have either A [adenine] or C [cytosine].) Uhl had shown that the VMAT2 polymorphism was highly associated with other VMAT2 mutations and could be used as a marker for the gene.
The fact that the protein made from the VMAT2 gene was involved in packaging all the monoamine neurotransmitters-Hamer's candidate endogenous molecules for self-transcendence and spirituality-made this gene a particularly attractive target for study. According to Hamer, "VMAT2 controls the flow of monoamines within the brain" and promotes a "higher consciousness."6 The packaging vesicles, besides delivering neurotransmitters to the synaptic cleft for signal transduction, protect these molecules from degradation by enzymes, particularly monoamine oxidases, which remove the neurotransmitter once the neuron fires and the signal has been sent.
Using a color-coded fluorescence assay for A33050C and a fast computer, Hamer compared his subjects' genotypes with their test scores on the Cloninger self-transcendence scale. "We hit pay dirt," is how Hamer described the result.
"There was a clear association between the VMAT2 polymorphism and self-transcendence. Individuals with a C in their DNA-on either one chromosome or both-scored significantly higher than those with an A... Somehow, this single-base change was affecting every facet of self-transcendence, from loving nature to loving God, from feeling at one with the universe to being willing to sacrifice for its improvement.
The VMAT2 gene variant containing a C-or "spiritual allele," as I began to think of it-was present on only 28% of chromosomes, compared with 72% carrying an A. But because both the C/C and the C/A genotypes had increased self-transcendence scores, compared to the A/A genotype, it worked out that 47%... were in the higher spirituality group, as compared with 53% in the lower group. ...While this one gene might not make one a saint, a prophet, or a seer, it was enough to tip the spiritual scales and predispose one toward spirituality (pp 73-74)".
Though Hamer claims that the VMAT2 polymorphism holds the key to understanding spirituality, he never explains why the C/C genotype is better than the A/A genotype in packaging and protecting brain monoamines from enzymatic degradation and other adverse fates.
God's hardwiring not empirically demonstrated
In searching out the God gene, Hamer wanted to know if consciousness can be explained "scientifically."
"By a scientific explanation, I mean one that can be expressed in terms of the basic principles of chemistry and physics. Proponents of this view often are called 'materialists' because they believe that all mental processes can ultimately be accounted for by a few basic physical laws. Most scientists, including myself, are materialists (p 94)."
As a materialist, Hamer must maintain that believing in God involves some kind of brain "wiring." Though the word hardwired appears in the subtitle of The God Gene, near the end of the text he offers this qualification.
"[J]ust because spirituality is partly genetic doesn't mean it is hardwired. Our genes are more like a family recipe handed down by word of mouth than a precise set of instructions that must be followed in exact detail. The final product depends a lot on how you interpret and execute the formula (pp 211-212)."
Hamer's materialism goes off on a curious metaphorical course here, right into the kitchen! In spite of this epigenetic qualification of his genetic theory of spirituality, and his acknowledgment that besides VMAT2 there may be other God genes, Hamer pushes through to his conclusion. We could ask what standard in science is being met here, or, for that matter, what standard in theology?
And then there is this question: However one might be impressed by the correlation between the VMAT2 gene polymorphism and spirituality, a difference in the vesicular covering of monoamine neurotransmitters in the brain seems to be a pretty small variant on which to hang so important and universal a phenomenon as the capacity for spirituality. One wonders how many other theories could have been put forward and how many other experiments could have been performed that would have also yielded "positive" results.
The "bottom up" explanations for religious belief and spirituality offered by neurotheologians and neurogeneticists derive from a science that sees our lives as being largely determined by biological factors. These theories are based on empirical data that have been "stretched" across a discontinuity that still separates the constructs of brain and mind.11 In spite of what some clinicians and theoreticians propose, no one can yet say how the brain-which is necessary for all activity that we recognize as human and is clearly a progenitor of what we call the mind-produces the contents of consciousness,12 including religious belief.
Acknowledgement: The author thanks David L. Smith, CSSp, PhD. His article on neurotheology cited here was Dr Muller's introduction to the subject, and he drew heavily from it in writing the first section of this article.
Neurotheology. Wikipedia. August 13, 2007. en. wikipedia.org/wiki/neurotheology. Accessed August 14, 2007.
Joseph R. The limbic system and the soul: evolution and the neuroanatomy of religious experience. Zygon. 2001;36:105-136.
Delio I. Are we wired for God? New Theol Rev. 2003; 16:31-43.
Smith DL. Does God slumber deep in the belly of the brain? A critique of neurotheology. Josephinum J Theol. 2006;13:81-99.
d'Aquili EG, Newberg AB. Religious and mystical states: a neuropsychological model. Zygon. 1993;28:177-200.
Hamer D. The God Gene: How Faith Is Hardwired Into Our Genes. New York: Doubleday; 2004.
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Griffiths RR, Richards WA, McCann U, Jesse R. Psilocybin can occasion mystical-type experiences having substantial sustained personal meaning and spiritual significance. Psychopharmacology. 2006;187:268-283.
Ellis RD. Phenomenology-friendly neuroscience: the return to Merleau-Ponty as psychologist. Hum Stud. 2006;29:33-55.
McHugh PR, Slavney PR. The Perspectives of Psychiatry. 2nd ed. Baltimore: The Johns Hopkins University Press; 1998:11-13.