The Believing Brain - Michael Shermer [92]
Of course, genes do not determine whether one chooses Judaism, Catholicism, Islam, or any other religion. Rather, belief in supernatural agents (God, angels, and demons) and commitment to certain religious practices (church attendance, prayer, rituals) appear to reflect genetically based cognitive processes (inferring the existence of invisible agents) and personality traits (respect for authority, traditionalism). Why did we inherit this tendency?
One line of research that may help answer this question is related to dopamine, which as we saw in chapter 6 is directly connected to learning, motivation, and reward. There may be a genetic basis to how much dopamine each of our brains produces. The gene that codes for the production of dopamine is called DRD4 (dopamine receptor D4) and is located on the short arm of the eleventh chromosome. When dopamine is released by certain neurons in the brain it is picked up by other neurons that are receptive to its chemical structure, thereby establishing dopamine pathways that stimulate organisms to become more active and reward certain behaviors that then get repeated. If you knock out dopamine from either a rat or a human, for example, they will become catatonic. If you overstimulate the production of dopamine, you get frenetic behavior in rats and schizophrenic behavior in humans.
The first people to associate the DRD4 gene with spirituality were medical researcher David Comings and his colleagues, when they went looking for genes associated with novelty seeking.12 Their research was subsequently picked up and linked to risk-taking behavior by National Cancer Institute geneticist Dean Hamer. Most of us have four to seven copies of the DRD4 gene on chromosome eleven. Some people, however, have two or three copies, while others have eight to eleven copies. More copies of the DRD4 gene translate into lower levels of dopamine, which stimulates people to seek greater risks in order to artificially get their dopamine fix. Leaping off of buildings, antennae, spans, or earth (so-called BASE jumping) is one way to do it, although high-risk gambling in Las Vegas or Wall Street may also do the trick. As a test of this hypothesis, Hamer first had subjects take a survey that measures desire to seek novelty and thrills. (BASE jumpers score very high on this test.) He then took a sample of their DNA from chromosome eleven and discovered that people with high numbers on the risk-taking survey had more copies than normal of the DRD4 gene.13
From risk-taking behavior to religious belief, Hamer considered the possibility that dopamine might be implicated in faith, and he published his results in a controversial book entitled The God Gene. To his credit, Hamer disclaims the book’s title (they are almost always determined by the sales and marketing departments of publishing companies), explaining that there is, of course, no single gene that could possibly represent something as complex and variegated as belief in God, much less the rich tapestry that is religious faith. But he does argue that some of us are born with genes that make us more or less “spiritual,” which is a component in both belief in God and religious faith.14 This time Hamer tagged another dopamine-related gene called VMAT2 (vesicular monoamine transporter 2), which regulates the flow of serotonin, adrenaline, norepinephrine, and our friend dopamine. Starting with a database of siblings with cigarette addiction, Hamer wanted to know if there was a family genetic connection to an addictive personality, and so gave his subjects a battery of psychological questionnaires, one of which included the personality trait self-transcendence.
First identified by Washington University psychiatrist Robert Cloninger, people scoring high in self-transcendence tend toward “self-forgetfulness” (becoming totally absorbed in an activity), “transpersonal identification