Monday, January 12, 2009

Gaia Shibboleth 2: Is Religiosity in the Genes?

Twins marrying twins in Russia

Religious belief has traditionally among social scientists been viewed as being largely a matter of culture and parental upbringing, that is until a series of twin studies, capped by Dean Hamer's 'The God Gene: How Faith is Hardwired into our Genes' (2) hit the pulp science shelves.

Hamer, having already written a controversial book on the 'gay gene' (1) which Carl Zimmer (3), in a critical review of 'The God Gene', noted "brought a huge media fanfare, but other scientists who tried to replicate the study failed", carried on to claim, on the basis of twin studies of other authors, and work he had done using his own study of smoking habits, that 'self transcendence', a measure of spiritual tendencies, had around 40% genetic heritability.

This raises all manner of issues on both the secular and religious sides of the debate about God, society and evolution. For some religious people, to say religiosity is merely a product of animal evolution is an insult to God's intelligently created design, however for others it is a sign that God intended his creation to be religious. To secular scientists, a genetic basis might also explain the social dominance of many religious systems as strategic belief systems, but it goes against the idea that religion and belief are part of culture and learning.

The self-transcendence scale is composed of three sub-sets: "self-forgetfulness" (as in the tendency to become totally absorbed in some activity, such as reading); "transpersonal identification" (a feeling of connectedness to a larger universe); and "mysticism" (an openness to believe things not literally provable, such as ESP). The difficulty with this as a measure is that it correlates as closely with trendy green environmentalism as it does with blue-blooded religious conservatism and with contemplative mysticism rather than the fundamentalism that causes major concern in the West.

Hamer claimed self-transcendence was associated with a particular variant of the VMAT2 Vesicular Monoamine Transporter gene, that plays a key role in regulating the levels of the brain chemicals serotonin, dopamine and norepinephrine, which made it more active, and Hamer suggests makes people more optimistic, which makes them healthier and likely to have more children. However this has little to do with issues of religious traditions imposing conservative social regimes, expansionist political aims and utopian visions of world domination.

The self-transcendence measure was shown to be heritable by classical twin studies conducted by Lindon Eaves and Nicholas Martin (4, 5, 7). Interestingly, these studies show that specific religious beliefs (such as belief in Jesus) have no genetic basis and are instead based on purely cultural transmission.

A happy reunion! Identical twin sisters who were separated at birth have been reunited after 35 years. Paula Bernstein and Elyse Schein discovered that they had been part of a secret social experiment. Researchers had kept them apart with different adoptive families to investigate theories over 'nature and nurture'. The twins, born in New York, said they might have remained oblivious if Elyse, who had been living in Paris, had not decided to look for her birth mother. She was told that the mother was not interested in meeting her, but was then informed she had an identical twin called Paula. Social workers eventually managed to reunite the pair. After their emotional meeting, twin sisters discovered that, they had been part of research conducted by psychologists - thought to be the only study of its kind on twins separated from infancy. This experiment was so secret that not even their adoptive parents were told the full truth. The twins tracked down and confronted the scientists behind the study, including Peter Neubauer, a child psychiatrist. They allege he showed no remorse and offered no apology. A year after the study ended, in 1980, the State of New York issued guidelines stopping the separating of identical twins by adoption. Mr Neubauer reportedly locked the study in a university archive not to be opened until 2066.

Follow up studies in more detail were reported in Twin Studies (5-9):

Kirk et. al. (5) investigating self-transcendence, gave heritability estimates of 37% and 41% for men and women respectively, whilst shared environment effects were not found to be significant. Modeling of self-transcendence and self-reported church attendance indicated substantially different etiologies for these variables, with shared environment playing a substantial role in church attendance behavior. This supports criticisms that church attendance alone is not necessarily an adequate measure of religiosity or spirituality, as it is evidently subject to different influences from those affecting a person’s more intrinsic characteristics.

The types of questions used give the closest idea of what 'self-transcendence' is measuring:

1. Often I have unexpected flashes of insight or understanding while relaxing
2. I often feel a strong spiritual or emotional connection with all the people around me
3. I often feel that I am a part of the spiritual force on which all life depends
4. I love the blooming of flowers in the spring as much as seeing an old friend again
5. I sometimes feel so connected to nature that everything seems to be part of one living organism
6. I seem to have a ‘sixth sense’ that sometimes allows me to know what is going to happen
7. Sometimes I have felt as if I was part of something with no limits or boundaries in time or space
8. I sometimes feel a spiritual connection to other people that I cannot explain in words
9. Sometimes I have felt my life was being directed by a spiritual force greater than any human being
10. I often become so fascinated with what I’m doing that I get lost in the moment – as if I’m detached from time and place
11. I have made real personal sacrifice in order to make the world a better place – like trying to prevent war, poverty and injustice
12. I have had personal experiences in which I felt in contact with a divine and wonderful spiritual power
13. I have had moments of great joy in which I suddenly had a clear, deep feeling of oneness with all that exists
14. I believe that all life depends on some spiritual order or power that cannot be completely explained
15. Often when I look at an ordinary thing, something wonderful happens – I get the feeling that I am seeing it fresh for the first time

Bouchard et. al. (6) investigating genetic and environmental influences on a somewhat different pair of measures Intrinsic (IR) and Extrinsic (ER) religiousness. The IR and ER scales distinguish between instrumental values (Extrinsic Religiousness) as a mode of conduct and terminal values (Intrinsic Religiousness) as an end state of existence: summed up as ‘the extrinsically motivated person uses his religion, whereas the intrinsically motivated person lives his religion’. Data on IR and ER from 35 pairs of monozygotic twins reared apart (MZA) and 37pairs of dizygotic twins reared apart (DZA) demonstrated significant heritability (43% and 39%), with a model containing genetic plus environmental factors fitting significantly better than a model containing only an environmental component. Twin similarity could not be explained by placement on a self-reported measure of family Moral Religious Emphasis. The questions in this study are substantially different and do come closer to measuring traditional religious values:

10. My religion is important because it answers many questions about the meaning of life. (IR) 0.77
1. I enjoy reading about my religion. (IR) 0.75
5. It is important to me to spend time in private thought and prayer. (IR) 0.74
20. I would prefer to go to my place of worship (IR) 0.74
6. I have often had a strong sense of God’s presence. (IR) 0.73
8. I try hard to live all my life according to my religious beliefs. (IR) 0.72
15. My whole approach to life is based on my religion. (IR) 0.71
18. Prayers I say when I’m alone are as important to me as those I say in my place of worship. (IR) 0.68
3. It doesn’t much matter what I believe as long as I am good. (ER) but IR= –0.63
11. I would rather join a religious study group (a group that studies the Bible, Koran, Torah or other religious text) than a social group at my place of worship (Church, Synagogue, Temple). (IR) 0.55
9. What religion offers me most is comfort in times of trouble and sorrow. (ER) IR=0.53 ER=0.36
12. Prayer is for peace and happiness. (ER) IR=0.44
19. Although I believe in my religion, many other things are more important in life. (ER) IR=–0.39
14. I go to my (Church, Synagogue, Temple) to spend time with my friends. (ER) 0.80
16. I go to my (Church, Synagogue, Temple) mainly because I enjoy seeing people that I know there. (ER) 0.79
2. I go to my place of worship (Church, Synagogue, Temple) because it helps me to make friends. (ER) 0.66
7. I pray mainly to gain relief and protection. (ER) 0.56
17. I pray mainly because I have been taught to pray. (ER) 0.50
4. Sometimes I have to ignore my religious beliefs because of what people might think of me. (ER) 0.42
13. Although I am religious, I don’t let it affect my daily life. (ER)

In a third study, Kirk et. al. (7) examined church attendance behavior in both in Australian and US populations. Although models fitted to the data from the two cohorts could not be equated, major influences appear to be additive genetic (15–35%), common environment (7–14%) and unique environment (35–48%), with small contributions from assortative mating (<10%), style="font-weight: bold;">

Robin Dunbar (10), a proponent of religion as an evolutionary trait, notes that evolutionary biologists have identified at least four ways in which religion might be of benefit in terms of evolutionary fitness. The first is to give sufficient explanatory structure to the universe to allow us to control it, perhaps through the intercession of God or a spirit world. The second is to make us feel better about life, or at least resigned to its worst vagaries - Marx's "opium of the masses". A third is that religions provide and enforce some kind of moral code, so keeping social order. Finally, religious belief might bring a sense of communality, of group membership.

Although the first is plausible and was supported by Freud, Dunbar suggests this doesn't make evolutionary sense as there is no real control of nature provided. The second is also plausible since recent sociological studies have shown that compared with non-religious people, the actively religious are happier, live longer, suffer fewer physical and mental illnesses, and recover faster from medical interventions such as surgery. Dunbar discounts the moral code thesis because he perceives it to be a more recent manifestation of organized world religions, rather than simple faiths held spontaneously by small bands of early humans, but opts for the sense of communality gained as the key, also favoured by Durkheim.

He suggests that religions bond societies because they exploit a whole suite of rituals that are extremely good at triggering the release of endorphins, natural opioids in the brain, noting that this may be why religious rituals so often involve activities that are physically stressful - singing, dancing, repetitive swaying or bobbing movements, awkward postures like kneeling or the lotus position, counting beads, and occasionally even seriously painful activities like self-flagellation.

Ape and monkey societies establish mutual trust through time-consuming mutual activities such as grooming. As human societies came to involve larger groups than such one-on-one contact provide, he suggests that gossip and then small-scale religious belief could have taken over the role of guarding against free-riders and social parasites.

Looking at the nature of theology cognitively, Dunbar suggests this involves fifth-order intentionality: "Take the statement: "I believe that god wants..." To grasp this an individual needs theory of mind - the capacity to understand that another individual (in this case, god) has a mind of his own. Philosophers call this "second-order intentionality" because such statements contain two notions of intent: I believe and god wants. But we need more than this to build a religion.

Third-order intentionality allows me to state: I believe that god wants us to act with righteous intent. At this level, I have personal religion. But if I am to persuade you to join me in this view, I have to add your mind state: I want you to believe that god wants us to act righteously. That's fourth-order intentionality, and it gives us social religion. Even now, you can accept the truth of my statement and still it commits you to nothing. But add a fifth level (I want you to know that we both believe that god wants us to act righteously) and now, if you accept the validity of my claim, you also implicitly accept that you believe it too. Now we have what I call communal religion: together, we can invoke a spiritual force that obliges, perhaps even forces, us to behave in a certain way."

He suggests Homo erectus would have aspired to third-order intentionality, perhaps allowing them to have personal beliefs about the world. Fourth-order intentionality - equating to social religion - appeared with archaic humans around 500,000 years ago. And fifth order didn't appear much before the evolution of anatomically modern humans around 200,000 years ago - early enough to ensure that all living humans share this trait, but late enough to suggest that it was probably a unique adaptation.

He points out the relationship between the brain's neocortex and social group size in primates, suggesting, this "social brain hypothesis" predicts that around the time our ancestors evolved the capacity for fifth-order intentionality their community sizes would have exceeded about 120 individuals. Religion may have evolved to provide the mechanism for bonding them into a coherent social unit.

In 'Born believers: How your brain creates God' (11) Michael Brooks looks at the alternative approach, that religion is not adaptive, but, are rather a natural consequence of the way humans perceive the world. Religious ideas are common to all cultures: like language and music, they seem to be part of what it is to be human. although, science has until recently shied away from asking why. "It's not that religion is not important," says Paul Bloom, a psychologist at Yale University, "it's that the taboo nature of the topic has meant there has been little progress."

However, religion-as-an-adaptation has its critics. Anthropologist Scott Atran points out, the evolutionary benefits of holding such unfounded beliefs are questionable. "I don't think the idea makes much sense, given the kinds of things you find in religion," he says. A belief in life after death, for example, is hardly compatible with surviving in the here-and-now and propagating your genes.

An alternative being put forward by Atran and others is that religion emerges as a natural by-product of the way the human mind works. "Children the world over have a strong natural receptivity to believing in gods because of the way their minds work, and this early developing receptivity continues to anchor our intuitive thinking throughout life," says anthropologist Justin Barrett.

Bloom and colleagues have shown that babies as young as five months make a distinction between inanimate objects and people. Shown a box moving in a stop-start way, babies show surprise. But a person moving in the same way elicits no surprise. To babies, objects ought to obey the laws of physics and move in a predictable way. People, on the other hand, have their own intentions and goals, and move however they choose.

Bloom says the two systems are autonomous, leaving us with two viewpoints on the world: one that deals with conscious minds, and one that handles bodies and physical aspects of the world. He calls this innate assumption "common-sense dualism". "We very naturally accept you can leave your body in a dream, or in astral projection or some sort of magic. These are universal views."

Roughly half of all 4-year-olds have had an imaginary friend, and adults often form and maintain relationships with dead relatives, fictional characters and fantasy partners. As Barrett points out, this is an evolutionarily useful skill. Without it we would be unable to maintain large social hierarchies and alliances or anticipate what an unseen enemy might be planning.

In 2004, Jesse Bering, put on a puppet show for a group of pre-school children in which an alligator ate a mouse. When asked 'physical' questions, such as: "Can the mouse still be sick? Does it need to drink?" The children said no. But when asked more 'spiritual' questions, such as "does the mouse think and know things?", the children answered yes. Bering thus considers a belief in some form of life apart from that experienced in the body to be the default setting of the human brain.

From there it is only a short step to conceptualising spirits, dead ancestors and, of course, gods, says psychologist Pascal Boyer, who points out that people expect their gods' minds to work very much like human minds, suggesting they spring from the same brain system that enables us to think about absent or non-existent people. Again, this over-attribution of cause and effect probably evolved for survival. If there are predators around, it is no good spotting them 9 times out of 10. Running away when you don't have to is a small price to pay for avoiding danger when the threat is real.

Deborah Kelemen of the University of Arizona in Tucson asked 7 and 8-year-old children questions about inanimate objects and animals, she found that most believed they were created for a specific purpose. Kelemen has found that adults are just as inclined to see design and intention where there is none. Put under pressure to explain natural phenomena, adults often fall back on teleological arguments, such as "trees produce oxygen so that animals can breathe" or "the sun is hot because warmth nurtures life". Her results also show that most adults tacitly believe they have souls.

In subsequent studies she has found that this tendency to favour explanations invoking purpose-seeking yet false explanations of natural phenomena - promiscuous teleology - is shared by both religious and non-religious adults, suggesting that humans are neurobiologically predisposed to be susceptible to 'intelligent design' and creationist explanations (Cognition (DOI: 10.1016/j.cognition.2009.01.001, Callaway, Ewen "Humans may be primed to believe in creation" New Scientist 2 Mar 2009).

In similar experiments, Olivera Petrovich of the University of Oxford asked pre-school children about the origins of natural things such as plants and animals. She found they were seven times as likely to answer that they were made by god than made by people. Although religious adults have very different mindsets from children, concentrating more on the moral dimensions of their faith and less on its supernatural attributes.

Even so, religion is an inescapable artefact of the wiring in our brain, says Bloom. "All humans possess the brain circuitry and that never goes away." Petrovich adds that even adults who describe themselves as atheists and agnostics are prone to supernatural thinking, particularly during traumatic moments in their lives.

In an experiment in Science (12) Jennifer Whitson and Adam A, asked people what patterns they could see in arrangements of dots or stock market information. Before asking, Whitson and Galinsky made half their participants feel a lack of control, either by giving them feedback unrelated to their performance or by having them recall experiences where they had lost control of a situation. The results were striking. The subjects who sensed a loss of control were much more likely to see patterns where there were none.

These findings also challenge the idea that religion is an adaptation. "Yes, religion helps create large societies - and once you have large societies you can outcompete groups that don't," Atran says. "But it arises as an artefact of the ability to build fictive worlds. I don't think there's an adaptation for religion any more than there's an adaptation to make airplanes."

Supporters of the adaptation hypothesis, however, say that the two ideas are not mutually exclusive and may be complementary.

In The God Delusion, Richard Dawkins argues that religion is propagated through indoctrination, especially of children: Evolution predisposes children to swallow whatever their parents and tribal elders tell them, as trusting obedience is valuable for survival, leading to "slavish gullibility" in the face of religious claims. Dawkins also sees the two approaches as complementary: "I am thoroughly happy with believing that children are predisposed to believe in invisible gods - I always was," says Dawkins. "But I also find the indoctrination hypothesis plausible. The two influences could, and I suspect do, reinforce one another."


1. Hamer, Dean (1994) The Science of Desire: The Search for the Gay Gene and the Biology of Behavior, Simon and Schuster.
2. Hamer, Dean (2004) The God Gene: How Faith Is Hard-Wired Into Our Genes Random House.
3. Zimmer Carl (2004) Faith-Boosting Genes A search for the genetic basis of spirituality Scientific American Oct 110-114.
4. Eaves L, Martin N, Heath A (1990) Religious Affiliation in Twins and Their Parents: Testing a Model of Cultural Inheritance Behavior Genetics, 20/1 1-22.
5. Kirk K, Eaves L, Martin N (1999) Self-transcendence as a measure of spirituality in a sample of older Australian twins Twin Research 2, 81–87.
6. Bouchard T, McGue M, Lykken D and Tellegen A (1999) Intrinsic and extrinsic religiousness: genetic and environmental influences and personality correlates Twin Research 2, 88–98.
7. Kirk K, HH Maes H, Neale M, AC Heath A, Martin N and Eaves L (1999) Frequency of church attendance in Australia and the United States: models of family resemblance Twin Research 2, 99–107.
8. Winter T, Kaprio J, Viken R, Karvonen S and Rose R (1999) Individual differences in adolescent religiosity in Finland: familial effects are modified by sex and region of residence Twin Research 2, 108–114
9. Boomsma D, de Geus E, van Baal G and Koopmans JA (1999) A religious upbringing reduces the influence of genetic factors on disinhibition: Evidence for interaction between genotype and environment on personality Twin Research 2, 115–125.
10. Dunbar, Robin (2006) Belief special: How evolution found God New Scientist 2536 28 Jan, 30.
11. Brooks Michael (2009) Born believers: How your brain creates God New Scientist 2694 4 Feb.
12. Whitson J, Galinsky Science 322, 115.

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