The Evolutionary Psychology of Religion

Steven Pinker
Harvard University

Presented at the annual meeting of the Freedom from Religion Foundation, Madison, Wisconsin, October 29, 2004, on receipt of “The Emperor’s New Clothes Award.”

Thank you very much; this is a tremendous honor. I look forward to displaying the Emperor proudly in my office at Harvard. It's a special honor to be here on the occasion that is recognizing the accomplishments of Anne Gaylor and I'd like to express my appreciation for the wonderful work that she has done in this Foundation.


Do we have a “God gene,” or a “God module”? I'm referring to claims that a number of you may have noticed. Just last week, a cover story of Time magazine was called "The God Gene: Does our deity compel us to seek a higher power?" Believe it or not, some scientists say yes. And a number of years earlier, there were claims that the human brain is equipped with a “God module,” a subsystem of the brain shaped by evolution to cause us to have a religious belief. "Brain's God module may affect religious intensity," according to the headline of the Los Angeles Times. In this evening's talk, I want to evaluate those claims.



There certainly is a phenomenon that needs to be explained, namely religious beliefs. According to surveys by ethnographers, religion is a human universal. In all human cultures, people believe that the soul lives on after death, that ritual can change the physical world and divine the truth, and that illness and misfortune are caused and alleviated by a variety of invisible person-like entities: spirits, ghosts, saints, evils, demons, cherubim or Jesus, devils and gods.



All cultures, you might ask? Yes, all cultures. I give you an example of a culture we're well familiar with, that of the contemporary United States. The last time I checked the figures, 25% of Americans believe in witches, 50% in ghosts, 50% in the devil, 50% believe that the Book of Genesis is literally true, 69% believe in angels, 87% believe Jesus was raised from the dead, and 96% believe in a god or a universal spirit. You've got your work cut out for you!



So what's going on? In many regards, the human mind appears to be well-engineered. Not literally well-engineered, but it has the signs or appearance of engineering in the biologist’s sense. That is, we can see, think, move, talk, understand, and attain goals better than any robot or computer. You can't go to Circuit City and buy Rosie the Maid from "The Jetsons" and expect to it to put away the dishes or run simple errands. These feats are too difficult for human-made creations, though they're things that a five-year-old child could do effortlessly. The explanation for signs of engineering in the natural world is Darwin's theory of national selection, the only theory we've come up with so far that can explain the illusion of design in causal terms.



The question is, how can a powerful taste for apparently irrational beliefs evolve? H.L. Mencken said that “the most common of all follies is to believe passionately in the palpably not true. It's the chief occupation of humankind.” This poses an enigma to the psychologist.



There is one way in which religious belief could be an adaptation. Many of our faculties are adaptations to enduring properties of the real world. We have depth perception, because the world really is three-dimensional. We apparently have an innate fear of snakes, because the world has snakes and they are venomous. Perhaps there really is a personal, attentive, invisible, miracle-producing, reward-giving, retributive deity, and we have a God module in order to commune with him. As a scientist, I like to interpret claims as testable hypotheses, and this certainly is one. It predicts, for example, that miracles should be observable, that success in life should be proportional to virtue, and that suffering should be proportional to sin. I don't know anyone who has done the necessary studies, but I would say there is good reason to believe that these hypotheses have not been confirmed. There's a Yiddish expression: "If God lived on earth, people would break his windows."



There have been other, more plausible attempts to explain religion as a biological adaptation. Even though I'm far more sympathetic to Darwinian explanations of mental life than most psychologists, I don't find any of these convincing.



The first is that religion gives comfort. The concepts of a benevolent shepherd, a universal plan, an afterlife, or just deserts, ease the pain of being a human; these comforting thoughts make us feel better. There's an element of truth to this, but it is not a legitimate adaptationist explanation, because it begs the question of why the mind should find comfort in beliefs that are false. Saying that something is so doesn't make it so, and there's no reason why it should be comforting to think it so, when we have reason to believe it is not so. Compare: if you're freezing, being told that you're warm is not terribly soothing. If you're being threatened by a menacing predator, being told that it's just a rabbit is not particularly comforting. In general, we are not that easily deluded. Why should we be in the case of religion? It simply begs the question.



The second hypothesis is that religion brings a community together. Those of you who read the cover story of Time might be familiar with this hypothesis because the geneticist Dean Hamer, whose new book The God Gene inspired the cover story, offered this as his Darwinian explanation of religion. Again I think again there's an element of truth in this. Religion certainly does bring a community together. But again it simply begs the question as to why. Why, if there is a subgoal in evolution to have people stand together to face off common enemies, would a belief in spirits, or a belief that ritual could change the future, be necessary to cement a community together? Why not just emotions like trust and loyalty and friendship and solidarity? There's no a priori reason you would expect a belief in a soul or a ritual would be a solution to the problem of how you get a bunch of organisms to cooperate.



The third spurious explanation is that religion is the source of our higher ethical yearnings. Those of you who read the book Rock of Ages by Steven Jay Gould, who argued that religion and science could co-exist comfortably, are familiar with his argument: since science can't tell us what our moral values should be, that's what religion is for, and each “magisterium” should respect the other. A big problem for this hypothesis is apparent to anyone who has read the Bible, which is a manual for rape and genocide and destruction. God tells the Israelites invading all Midianite villages, “Kill all the men, kill all the kids, kill all the old women. The young women that you find attractive, bring them back to your compound, lock them up, shave their heads, lock them in a room for 30 days till they stop crying their eyes out because you've killed their mom and dad, and then take her as a second or third or fourth or fifth wife." So the Bible, contrary to what a majority of Americans apparently believe, is far from a source of higher moral values. Religions have given us stonings, witch-burnings, crusades, inquisitions, jihads, fatwas, suicide bombers, gay-bashers, abortion-clinic gunmen, and mothers who drown their sons so they can happily be united in heaven.



To understand the source of moral values, we don’t have to look to religion. Psychologists have identified universal moral sentiments such as love, compassion, generosity, guilt, shame, and righteous indignation. A belief in spirits and angels need have anything to do with it. And moral philosophers such as Peter Singer (one of tomorrow’s honorees) who scrutinize the concept of morality have shown that it is logically rooted in the interchangeability of one's own interests and others. The world's enduring moral systems capture in some way the notion of the interchangeability of perspectives and interests, the idea that "I am one guy among many": the golden rule; the categorical imperative; Singer's own notion of “the expanding circle,” John Rawls' “veil of ignorance,” and so on. A retributive, human-like deity meting out justice doesn't have a role in our best explanations of the logic of morality.



To answer the “why is Homo sapiens so prone to religious belief?” you first have to distinguish between traits that are adaptations, that is, products of Darwinian natural selection, and traits that are byproducts of adaptations, also called spandrels or exaptations. An example: Why is our blood red? Is there some adaptive advantage to having red blood, maybe as camouflage against autumn leaves? Well, that’s unlikely, and we don't need any other adaptive explanation, either. The explanation for why our blood is red is that it is adaptive to have a molecule that can carry oxygen, mainly hemoglobin. Hemoglobin happens to be red when it's oxygenated, so the redness of our blood is a byproduct of the chemistry of carrying oxygen. The color per se was not selected for. Another non-adaptive explanation for a biological trait is genetic drift. Random stuff happens in evolution. Certain traits can become fixed through sheer luck of the draw.



To distinguish an adaptation from a byproduct, first of all you have to establish that the trait is in some sense innate, for example, that it develops reliably across a range of environments and is universal across the species. That helps rule out reading, for example, as a biological adaptation. Kids don't spontaneously read unless they are taught, as opposed to spoken language, which is a plausible adaptation, because it does emerge spontaneously in all normal children in all societies.



The second criterion is the causal effects of the trait would, on average, have improved the survival or reproduction of the bearer of that trait in an ancestral environment -- the one in which our species spent most of its evolutionary history, mainly the foraging or hunter-gatherer lifestyle that predated the relatively recent invention of agriculture and civilization.



Crucially, the advantage must be demonstrable by some independently motivated causal consequences of the putative adaptation. That is, the laws of physics or chemistry or engineering have to be sufficient to establish that the trait would be useful. The usefulness of the trait can't be invented ad hoc; if it is, you have not a legitimate evolutionary explanation but a “just-so story” or fairy tale. The way to tell them apart is to independently motivate the usefulness of the trait. An example: Via projective geometry, one can show that by combining images from two cameras or optical devices, it is possible to calculate the depth of an object from the disparity of the projections. If you write out the specs for what you need in order to compute stereoscopic depth, you find that humans and other primates seem to have exactly those specs in our sense of stereoscopic depth perception. It's exactly what engineers would design if they were building a robot that had to see in depth. That similarity is a good reason to believe that human stereoscopic depth perception is an adaptation.



Likewise for fear of snakes. In all societies people have a wariness of snakes; one sees it even in laboratory-raised monkeys who had never seen a snake. We know from herpetology that snakes were prevalent in Africa during the time of our evolution, and that getting bitten by a snake is not good for you because of the chemistry of snake venom. Crucially, that itself is not a fact of psychology, but it helps to establish that what is a fact of psychology, namely the fear of snakes, is a plausible adaptation.



Our sweet tooth is yet another example. It’s not terribly adaptive now, but biochemistry has established that sugar is packed with calories, and therefore could have prevented starvation in an era which food sources were unpredictable. That makes a sweet tooth a plausible adaptation.



In contrast, it's not clear what the adaptive function of humor is, or of music. I think the explanations of religion that I've reviewed have the same problem, namely not having an independent rationale, given an engineering analysis of why that trait should, in principle, be useful.



The alternative, then, is that just as the redness of blood is a by-product of other adaptations, so may our predisposition to religious belief. A crucial corollary of the theory of evolution is that conflicts of interests among organisms, of different species or of the same species, lead to the biological equivalent of an arms race. An organism evolves more clever or lethal weapons, another organism evolves even more ingenious defenses, and so on, spiraling the process spiral. At any given stage in an arms race, a feature can be adaptive for one organism but not for its adversaries, as long as the first is overcoming the defenses of the second. That's another reason why not everything in biology is adaptive, at least not for every organism. What's adaptive for the lion is not so adaptive for the lamb.



So a way of rephrasing the question “Why is religious belief so pervasive?” is to ask, Who benefits? Another way of putting it is that one must distinguish the possible benefits of religion to the producers of religious belief – the religious establishment of shamans and priests and so on—from the benefits to the consumers of religion -- the parishioners, the flock, the believers. The answer might be different for the two cases. One must distinguish the question "What good is an inculcation of religious belief by priests, shaman, and so on?" from the question "What good is an acceptance of religious belief by believers?"



A number of anthropologists have pointed out the benefits of religion to those causing other people to have religious beliefs. One ubiquitous component of religion is ancestor worship. And ancestor worship must sound pretty good if you're getting on in years and can foresee the day when you're going to become an ancestor. Among the indignities of growing old is that you know that you're not going to be around forever. If you plausibly convince other people that you'll continue to oversee their affairs even when you're dead and gone, that gives them an incentive to treat you nicely up to the last day.



Food taboos are also common in religious belief, and might be explained by the psychology of food preference and dispreference, in particular, disgust. If you withhold a food, especially a food of animal origin, from children during a critical period, they'll grow up grossed out at the thought of eating that food. That's why most of us would not eat dog meat, monkey brains, or maggots, things that are palatable in other societies. There are often ecological reasons why food taboos develop, but there are probably also reasons of control. Since neighboring groups have different favored foods, if you keep your own kids from having a taste for the foods favored by your neighbors, it can keep them inside the coalition, preventing them from defecting to other coalitions, because to break bread with their neighbors they'd have to eat revolting stuff.



Rites of passage are another intelligible feature of religion. Many social decisions have to be made in categorical, yes-or-no, all-or-none fashion. But a lot of our biology is fuzzy and continuous. A child doesn't go to bed one night and wake up an adult the next morning. But we do have to make decisions such as whether they can vote or drive or buy a gun. There's nothing magical about the age of 13 or the age of 18 or any other age. But it's more convenient to arbitrarily anoint a person as an adult on a particular, arbitrarily chosen day, than to haggle over how mature every individual is every time he wants a beer. Religious rites of passage demarcate stages of life, serving the function that we have given over to driver's licenses and other forms of ID. Another fuzzy continuum is whether someone is available as a potential romantic partner or are committed to someone else. Marriage is a useful way of demarcating that continuum with a sharp line.



Costly initiations or sacrifices are also present in almost all the world's religions. A general problem in the maintenance of cooperation is how to distinguish people who are altruistically committed to a coalition from hangers-on and parasites and free-riders. One way to test who's genuinely committed is to see who is willing to undertake a costly sacrifice. To take an example close to home: To see whether someone is committed to an ethnic group I am familiar with, you can say, "You've just had a baby. Please hand over your son so I can cut some skin off his penis." That's not the kind of thing that anyone would do unless they took their affiliation with the group seriously. And there are far more gruesome examples from the rest of the world.



Yet another explicable feature of religion is signs of expertise in occult knowledge. If you're the one who knows mysterious but important arcane knowledge, then other people will defer to you. Even in non-religious contexts, most societies have some division of labor in expertise, where we accord prestige and perquisites to people who know useful stuff. So a good strategy for providers of religion is to mix some genuine expertise -- and indeed, anthropologists have shown that the tribal shaman or witch doctor really is an expert in herbal medicine and folk remedies – with a certain amount of hocus-pocus, trance-inducing drugs, stage magic, sumptuous robes and cathedrals, and so on, reinforcing the claim that there are worlds of incomprehensible wonder, power, and mystery that are reachable only through one's services.



These practical benefits take some of the mystery over why people like to encourage religious belief in others, without committing oneself to a specific biological adaptation for religion. The inculcation of religious belief would be a byproduct of these other, baser, motives.



What about the other side of these transactions, namely the consumers? Why do they buy it? One reason is that in most cases we should defer to experts. That's in the very nature of expertise. If I have a toothache, I open my mouth and let a guy drill my teeth. If I have a bellyache, I let him cut me open. That involves a certain amount of faith. Of course, in these cases the faith is rational, but that deference could, if manipulated, lead to irrational deference, even if the larger complex of deference can be adaptive on the whole.



There are also emotional predispositions which evolved for various reasons and make us prone to religious belief as a by-product. The anthropologist Ruth Benedict summed up much of prayer when she said, "Religion is universally a technique for success.” Ethnographic surveys suggest that when people try to communicate with God, it's not to share gossip or know-how; it’s to ask him for stuff: recovery from illness, recovery of a child from illness, success in enterprises, success in the battlefield. (And of course, the Red Sox winning the World Series, which almost made me into a believer.) This idea was summed up by Ambrose Bierce in The Devil's Dictionary, which defines "to pray" as "to ask that the laws of the universe be annulled in behalf of a single petitioner, confessedly unworthy." This aspect of religious belief is thus a desperate measure that people resort to when the stakes are high and they've exhausted the usual techniques for the causation of success.



Those are some of the emotional predispositions that make people fertile ground for religious belief. But there also are cognitive predispositions, ways in which we intellectually analyze the world, which have been very skillfully explored by the anthropologists Dan Sperber, Pascal Boyer, and Scott Atran. Anyone who is interested in the evolutionary psychology of religion would enjoy Pascal Boyer’s Religion Explained and Scott Atran called In Gods We Trust. Hamer's The God Gene is also good, but I am more sympathetic to Boyer and Atran.



The starting point is a faculty of human reason that psychologists call intuitive psychology or the “theory of mind module” – “theory” here not referring to a theory of the scientist but rather to the intuitive theory that people unconsciously deploy in making sense of other people's behavior. When I try to figure out what someone is going to do, I don't treat them as just a robot or a wind-up doll responding to physical stimuli in the world. Rather, I impute minds to those people. I can't literally know what someone else is thinking or feeling, but I assume that they're thinking or feeling something, that they have a mind, and I explain their behavior in terms of their beliefs and their desires. That's intuitive psychology. There is evidence that intuitive psychology is a distinct part of our psychological make-up. It seems to be knocked out in a condition called autism: autistic people can be prodigious in mathematics, art, language, and music, but they have a terrible time attributing minds to other people. They really do treat other people as if they were robots and wind-up dolls. There's also a concerted effort underway to see where intuitive psychology is computed in the brain. Parts of it seems to be concentrated in the ventromedial and orbital frontal cortex, the parts of the brain that kind of sit above the eyeballs, as well as the superior temporal sulcus farther back.



Perhaps the ubiquitous belief in spirits, souls, gods, angels, and so on, consists of our intuitive psychology running amok. If you are prone to attributing an invisible entity called “the mind” to other people’s bodies, it's a short step to imagining minds that exist independently of bodies. After all, it's not as if you could reach out and touch someone else's mind; you are always making an inferential leap. It's just one extra inferential step to say that a mind is not invariable housed in a body.



In fact the 19th-century anthropologist Edward Tyler pointed out that in some ways, there is good empirical support for the existence of the soul, or at least there used to be, until the fairly recent advent of neuroscience, which provides an alternative explanation for how minds work. Think about dreams. When you dream, your body is in bed the whole time, but some part of you seems to be up and about in the world. The same thing happens when you're in a trance from a fever, a hallucinogenic drug, sleep deprivation, or food poisoning.



Shadows and reflections are rather mysterious, or were until the development of the physics of light with its explanation of those phenomena. But they appear to have the form and essence of the person but without any of their actual matter.



Death, of course, is the ultimate apparent evidence for the existence of the soul. A person may be walking around and seeing and hearing one minute, and the next minute be an inert and lifeless body, perhaps without any visible change. It would seem that some animating entity that was housed in the body has suddenly escaped from it.



So before the advent of modern physics, biology and especially neuroscience, a plausible explanation of these phenomena is that the soul wanders off when we sleep, lurks in the shadows, looks back at us from a surface of a pond, and leaves the body when we die.



To sum up. The universal propensity toward religious belief is a genuine scientific puzzle. But many adaptationist explanations for religion, such as the one featured in Time last week, don't, I think, meet the criteria for adaptations. There is an alternative explanation, namely that religious psychology is a by-product of many parts of the mind that evolved for other purposes. Among those purposes one has to distinguish the benefits to the producer and the benefits to the consumer. Religion has obvious practical effects for producers. When it comes to the consumers, there are possible emotional adaptations in our desire for health, love and success, possible cognitive adaptations in our intuitive psychology, and many aspects of our experience that seem to provide evidence for souls. Put these together and you get an appeal to a mysterious world of souls to bring about our fondest wishes.



Is God in Our Genes?


A provocative study asks whether religion is a product of evolution. Inside a quest for the roots of faith

By Jeffrey Kluger

It’s not hard to see the divinity behind the water temples that dot the rice terraces of Bali. It’s there in the white-clad high priest presiding in the temple at the summit of a dormant volcano. It’s there in the 23 priests serving along with him, selected for their jobs when they were still children by a bevy of virgin priestesses. It’s there in the rituals the priests perform to protect the island’s water, which in turn is needed to nurture the island’s rice.

If the divine is easy to spot, what’s harder to make out is the banal. But it’s there too—in the meetings the priests convene to schedule their planting dates and combat the problem of crop pests; in the plans they draw up to maintain aqueducts and police conduits; in the irrigation proposals they consider and approve, the dam proposals they reject or amend. “The religion has a temple at every node in the irrigation system,” says David Sloan Wilson, professor of biology and anthropology at Binghamton University in Binghamton, New York. “The priests make decisions and enforce the code of both religion and irrigation.”

Ask true believers of any faith to describe the most important thing that drives their devotion, and they’ll tell you it’s not a thing at all but a sense—a feeling of a higher power far beyond us. Western religions can get a bit more doctrinaire: God has handed us laws and lore, and it’s for us to learn and practice what they teach. For a hell-raising species like ours, however—with too much intelligence for our own good and too little discipline to know what to do with it—there have always been other, more utilitarian reasons to get religion. Chief among them is survival. Across the eons, the structure that religion provides our lives helps preserve both mind and body. But that, in turn, has raised a provocative question, one that’s increasingly debated in the worlds of science and religion: Which came first, God or the need for God? In other words, did humans create religion from cues sent from above, or did evolution instill in us a sense of the divine so that we would gather into the communities essential to keeping the species going?

Just as a hurricane spins off tornadoes, this debate creates its own whirlwind of questions: If some people are more spiritual than others, is it nature or nurture that has made them so? If science has nothing to do with spirituality and it all flows from God, why do some people hear the divine word easily while others remain spiritually tone-deaf? Do such ivied-hall debates about environment, heredity and anthropology have any place at all in more exalted conversations about the nature of God?

Even among people who regard spiritual life as wishful hocus-pocus, there is a growing sense that humans may not be able to survive without it. It’s hard enough getting by in a fang-and-claw world in which killing, thieving and cheating pay such rich dividends. It’s harder still when there’s no moral cop walking the beat to blow the whistle when things get out of control. Best to have a deity on hand to rein in our worst impulses, bring out our best and, not incidentally, give us a sense that there’s someone awake in the cosmic house when the lights go out at night and we find ourselves wondering just why we’re here in the first place. If a God or even several gods can do all that, fine. And if we sometimes misuse the idea of our gods—and millenniums of holy wars prove that we do—the benefits of being a spiritual species will surely outweigh the bloodshed.

Far from being an evolutionary luxury then, the need for God may be a crucial trait stamped deeper and deeper into our genome with every passing generation. Humans who developed a spiritual sense thrived and bequeathed that trait to their offspring. Those who didn’t risked dying out in chaos and killing. The evolutionary equation is a simple but powerful one.

Nowhere has that idea received a more intriguing going-over than in the recently published book The God Gene: How Faith Is Hardwired into Our Genes by molecular biologist Dean Hamer. Chief of gene structure at the U.S. National Cancer Institute, Hamer not only claims that human spirituality is an adaptive trait, but he also says he has located one of the genes responsible, a gene that just happens to also code for production of the neurotransmitters that regulate our moods. Our most profound feelings of spirituality, according to a literal reading of Hamer’s work, may be due to little more than an occasional shot of intoxicating brain chemicals governed by our dna. “I’m a believer that every thought we think and every feeling we feel is the result of activity in the brain,” Hamer says. “I think we follow the basic law of nature, which is that we’re a bunch of chemical reactions running around in a bag.”

Even for the casually religious, such seeming reductionism can rankle. The very meaning of faith, after all, is to hold fast to something without all the tidy cause and effect that science finds so necessary. Try parsing things the way geneticists do, and you risk parsing them into dust. “God is not something that can be demonstrated logically or rigorously,” says Neil Gillman, a professor of Jewish philosophy at the Jewish Theological Seminary in New York City. “[The idea of a God gene] goes against all my personal theological convictions.” John Polkinghorne, a physicist who is also Canon Theologian at England’s Liverpool Cathedral, agrees: “You can’t cut [faith] down to the lowest common denominator of genetic survival. It shows the poverty of reductionist thinking.”

Is Hamer really guilty of such simplification? Could claims for a so-called God gene be merely the thin end of a secular wedge, one that risks prying spirituality away from God altogether? Or, assuming the gene exists at all, could it somehow be embraced by both science and religion, in the same way some evolutionists and creationists—at least the less radicalized ones—accept the idea of a divinely created universe in which evolving life is simply part of the larger plan? Hamer, for one, hopes so. “My findings are agnostic on the existence of God,” he says. “If there’s a God, there’s a God. Just knowing what brain chemicals are involved in acknowledging that is not going to change the fact.”

Whatever the merits of Hamer’s work, he is clearly the heir of a millenniums-long search for the wellsprings of spirituality. People have been wrestling with the roots of faith since faith itself was first codified into Scripture. “[God has] set eternity in the hearts of men,” says the Book of Ecclesiastes, “yet they cannot fathom what God has done from beginning to end.”

To theologians in the 3rd century B.C., when Ecclesiastes is thought to have been written, that passage spoke to the idea that while all of us are divinely inspired to look for God, none of us are remotely capable of fully comprehending what we are seeking. Scientists in the 21st century may not disagree, provided that “hearts of men” is replaced with “genes of men.” The key for those researchers is finding those genes.

Hamer began looking in 1998, when he was conducting a survey on smoking and addiction for the National Cancer Institute. As part of his study, he recruited more than 1,000 men and women, who agreed to take a standardized, 240-question personality test called the Temperament and Character Inventory (tci). Among the traits the tci measures is one known as self-transcendence, which consists of three other traits: self-forgetfulness, or the ability to get entirely lost in an experience; transpersonal identification, or a feeling of connectedness to a larger universe; and mysticism, or an openness to things not literally provable. Put them all together, and you come as close as science can to measuring what it feels like to be spiritual. “This allows us to have the kind of experience described as religious ecstasy,” says Robert Cloninger, a psychiatrist at Washington University in St. Louis, Missouri, and the designer of the self-transcendence portion of the tci.

Hamer decided to use the data he gathered in the smoking survey to conduct a little spirituality study on the side. First he ranked the participants along Cloninger’s self-transcendence scale, placing them on a continuum from least to most spiritually inclined. Then he went poking around in their genes to see if he could find the dna responsible for the differences. Spelunking in the human genome is not easy, what with 35,000 genes consisting of 3.2 billion chemical bases. To narrow the field, Hamer confined his work to nine specific genes known to play major roles in the production of monoamines—brain chemicals, including serotonin, norepinephrine and dopamine, that regulate such fundamental functions as mood and motor control. It’s monoamines that are carefully manipulated by Prozac and other antidepressants. It’s also monoamines that are not so carefully scrambled by ecstasy, lsd, peyote and other mind-altering drugs—some of which have long been used in religious rituals.

Studying the nine candidate genes in dna samples provided by his subjects, Hamer quickly hit the genetic jackpot. A variation in a gene known as vmat2—for vesicular monoamine transporter—seemed to be directly related to how the volunteers scored on the self-transcendence test. Those with the nucleic acid cytosine in one particular spot on the gene ranked high. Those with the nucleic acid adenine in the same spot ranked lower. “A single change in a single base in the middle of the gene seemed directly related to the ability to feel self-transcendence,” Hamer says. Merely having that feeling did not mean those people would take the next step and translate their transcendence into a belief in—or even a quest for—God. But they seemed likelier to do so than those who never got the feeling at all.

Hamer is careful to point out that the gene he found is by no means the only one that affects spirituality. Even minor human traits can be governed by the interplay of many genes; something as complex as belief in God could involve hundreds or even thousands. “If someone comes to you and says, ‘We’ve found the gene for X,’” says John Burn, medical director of the Institute of Human Genetics at the University of Newcastle in England, “you can stop them before they get to the end of the sentence.”

Hamer also stresses that while he may have located a genetic root for spirituality, that is not the same as a genetic root for religion. Spirituality is a feeling or a state of mind; religion is the way that state gets codified into law. Our genes don’t get directly involved in writing legislation. As Hamer puts it, perhaps understating a bit the emotional connection many have to their religions, “Spirituality is intensely personal; religion is institutional.”

At least one faith, according to one of its best-known scholars, formalizes the idea of gene-based spirituality and even puts a pretty spin on it. Buddhists, says Robert Thurman, professor of Buddhist studies at Columbia University, have long entertained the idea that we inherit a spirituality gene from the person we were in a previous life. Smaller than an ordinary gene, it combines with two larger physical genes we inherit from our parents, and together they shape our physical and spiritual profile. Says Thurman: “The spiritual gene helps establish a general trust in the universe, a sense of openness and generosity.” Buddhists, he adds, would find Hamer’s possible discovery “amusing and fun.”

The Buddhist theory has never been put to the scientific test, but other investigations into the biological roots of belief in God were being conducted long before Hamer’s efforts—often with intriguing results. In 1979, investigators at the University of Minnesota began their now famous twins study, tracking down 53 pairs of identical twins and 31 pairs of fraternal twins that had been separated at birth and raised apart. The scientists were looking for traits the members of each pair had in common, guessing that the characteristics shared more frequently by identical twins than by fraternal twins would be genetically based, since identical twins carry matching dna, and those traits for which there was no disparity between the identicals and fraternals would be more environmentally influenced.

As it turned out, the identical twins had plenty of remarkable things in common. In some cases, both suffered from migraine headaches, both had a fear of heights, both were nail biters. Some shared little eccentricities, like flushing the toilet both before and after using it. When quizzed on their religious values and spiritual feelings, the identical twins showed a similar overlap. In general, they were about twice as likely as fraternal twins to believe as much—or as little—about spirituality as their sibling did. Significantly, these numbers did not hold up when the twins were questioned about how faithfully they practiced any organized religion. Clearly, it seemed, the degree to which we observe rituals such as attending services is mostly the stuff of environment and culture. Whether we’re drawn to God in the first place is hardwired into our genes. “It completely contradicted my expectations,” says University of Minnesota psychologist Thomas Bouchard, one of the researchers involved in the work. Similar results were later found in larger twin studies in Virginia and Australia.

Other researchers have taken the science in a different direction, looking not for the genes that code for spirituality but for how that spirituality plays out in the brain. Neuroscientist Andrew Newberg of the University of Pennsylvania School of Medicine has used several types of imaging systems to watch the brains of subjects as they meditate or pray. By measuring blood flow, he determines which regions are responsible for the feelings the volunteers experience. The deeper that people descend into meditation or prayer, Newberg found, the more active the frontal lobe and the limbic system become. The frontal lobe is the seat of concentration and attention; the limbic system is where powerful feelings, including rapture, are processed. More revealing is the fact that at the same time these regions flash to life, another important region—the parietal lobe at the back of the brain—goes dim. It’s this lobe that orients the individual in time and space. Take it off-line, and the boundaries of the self fall away, creating the feeling of being at one with the universe. Combine that with what’s going on in the other two lobes, and you can put together a profound religious experience.

Even to some within the religious community, this does not come as news. “In India in Buddha’s time, there were philosophers who said there was no soul; the mind was just chemistry,” says Thurman. “The Buddha disagreed with their extreme materialism but also rejected the ‘absolute soul’ theologians.” Michael Persinger, professor of behavioral neuroscience at Laurentian University in Sudbury, Ont., puts the chemistry argument more bluntly. “God,” he says, “is an artifact of the brain.”

Even if such spiritual deconstructionism is true, some scientists—to say nothing of most theologians—think it takes you only so far, particularly when it comes to trying to determine the very existence of God. Simply understanding the optics and wiring of the eyes, after all, doesn’t mean there’s no inherent magnificence in the Rembrandts they allow us to see. If human beings were indeed divinely assembled, why wouldn’t our list of parts include a genetic chip that would enable us to contemplate our maker?

“Of course, concepts of God reside in the brain. They certainly don’t reside in the toe,” says Lindon Eaves, director of the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University in Richmond. “The question is, To what is this wiring responsive? Why is it there?”

Says Paul Davies, professor of natural philosophy at Macquarie University in Sydney, Australia: “I think a lot of people make the mistake of thinking that if you explain something, you explain it away. I don’t see that at all with religious experience.”

Those religious believers who are comfortable with the idea that God genes are the work of God should have little trouble making the next leap: that not only are the genes there but they are central to our survival, one of the hinges upon which the very evolution of the human species turned. It’s an argument that’s not terribly hard to make.

For one thing, God is a concept that appears in human cultures all over the globe, regardless of how geographically isolated they are. When tribes living in remote areas come up with a concept of God as readily as nations living shoulder to shoulder, it’s a fairly strong indication that the idea is preloaded in the genome rather than picked up on the fly. If that’s the case, it’s an equally strong indication that there are very good reasons it’s there.

One of those reasons might be that, as the sole species—as far as we know—capable of contemplating its own death, we needed something larger than ourselves to make that knowledge tolerable. “Anticipation of our own demise is the price we pay for a highly developed frontal lobe,” says Persinger. “In many ways, [a God experience is] a brilliant adaptation. It’s a built-in pacifier.”

But the most important survival role religion may serve is as the mortar that holds a group together. Worshipping God doesn’t have to be a collective thing; it can be done in isolation, disconnected from any organized religion. The overwhelming majority of people, however, congregate to pray, observing the same rituals and heeding the same creeds. Once that congregation is in place, it’s only a small step to using the common system of beliefs and practices as the basis for all the secular laws that keep the group functioning.

One of the best examples of religion as social organizer, according to Binghamton University’s Wilson, is early Calvinism. John Calvin rose to prominence in 1536 when, as a theologian and religious reformer, he was recruited to help bring order to the fractious city of Geneva. Calvin, perhaps one of the greatest theological minds ever produced by European Christianity, was a lawyer by trade. Wilson speculates that it was Calvin’s pragmatic genius to understand that while civil laws alone might not be enough to bring the city’s deadbeats and other malefactors into line, divine law might be.

Calvin’s catechism included the familiar Ten Commandments—which, with their injunctions against theft, murder, adultery and lying, are themselves effective social organizers. Added to that were admonitions to pay taxes, perform civic duties, behave in a civil manner and submit to the authority of magistrates. “You must understand religions very thoroughly in relation to their environments,” says Wilson. “And one problem for Calvin was to make his city function.”

The heirs to Calvinism today—Presbyterians, many Baptists and believers in the Reformed tradition in general—see the roots of their faith as something far more divine than merely good civic management. But even some theologians seem to think that a deep belief in the laws of God can coexist with the survival demands of an evolving society. “Calvin had a reverence for the Scriptures, which then became institutionalized,” says James Kay, professor of practical theology at the Princeton Theological Seminary. “The Bible is concerned about justice for the poor, equity and fairness, and all of those things were seen to in Calvin’s Geneva.”

Other struggling cultures have similarly translated godly law into earthly order and in doing so helped ensure their survival. The earliest Christians established a rough institutional structure that allowed them to transmit their ideas within a generation of Christ’s death, and as a result succeeded in living through the Roman persecution; the Jews of the Diaspora moved as a cultural whole through the nations of Europe, finding niches wherever they could but maintaining their identity and kinship by observing the same rites. “All religions become a bit secular,” says Wilson. “In order to survive, you have to organize yourselves into a culture.”

The downside to all this is that often religious groups gather not into congregations but into camps—and sometimes they’re armed camps. In a culture of Crusades, Holocausts and jihads, where in the world is the survival advantage of religious wars or terrorism? One facile explanation has always been herd culling—an adaptive way of keeping populations down so that resources aren’t depleted. But there’s little evolutionary upside to wiping out an entire population of breeding-age males, as countries trying to recover from wars repeatedly learn. Why then do we so often let the sweetness of religion curdle into combat?

The simple answer might be that just because we’re given a gift, we don’t necessarily always use it wisely. Fire can either light your village or burn down the one next door, depending on your inclination. “Religions represent an attempt to harness innate spirituality for organizational purposes—not always good,” says Macquarie University’s Davies. And while spiritual contemplation is intuitive, says Washington University’s Cloninger, religion is dogmatic; dogma in the wrong hands has always been a risky thing.

Still, for every place in the world that’s suffering from religious strife, there are many more where spirituality is doing its uplifting and civilizing work. A God who would equip us with the genes and the smarts to cooperate in such a clever way is a God who ought to be appealing even to religious purists. Nonetheless, sticking points do remain that prevent genetic theory from going down smoothly. One that’s particularly troublesome is the question of why Hamer’s God gene—or any of the others that may eventually be discovered—is distributed so unevenly among us. Why are some of us spiritual virtuosos, while others can’t play a note? Isn’t it one of the central tenets of religion that grace is available to everybody? At least a few scientists shrug at the question. “Some get religion, and some don’t,” says Virginia Commonwealth University’s Eaves.

But this seeming inequity may be an important part of the spiritual journey.