May 26, 2009
The biology of faith
The battle for your soul rages in your DNA, says Prof Steve Jones
An odd business, religion, and not one - or so it appears - that has much to do with science. To me, it has always seemed no more than a bunch of silly old men in frocks squabbling, often murderously, about who has the best dress designer, but I accept that faith can add real purpose to some people's lives.
Why such a difference in attitude? I ascribe my agnosticism to compulsory school assembly, which long ago immunised me against the divine, but some of my fellow pupils came out of the experience as keen followers of the church. Now, the new science of molecular theology is moving in on why we respond to sermonising in such separate ways.
What unites all believers is the notion of a higher being who watches over them. To St Teresa of Avila, her ecstatic fusions with God were "a sort of fainting fit, which takes over breath and all the forces of the body so that one can no longer say a word", which is a pretty biological description of the sanctified state.
But what kind of biology is involved? Magnetic resonance imaging scans, those gaudy icons of quasi-science, show that meditating monks reduce blood flow in the cerebral cortex (although that does not prove much: the diabolical fury when a mug of coffee spills into one's lap changes brain activity too).
Some even claim to have found the molecule for faith. It is, they say, the nerve transmitter serotonin, the target of Prozac, a substance much involved in hunger, sleep, depression, and more. Some of the hallucinogens used by certain religions to attain a godly state attach themselves to its brain receptors and St Teresa's fainting fits might have been due to a sudden surge of the stuff.
Not everyone is convinced, for serotonin is, like the Holy Spirit, a little too all-pervading for those of a sceptical turn of mind. Even so, some theologians claim that humans are as much programmed by DNA to believe as they are to stand upright.
The more interesting question is whether individual differences in religious experience are influenced by genes. Inheritance is obviously involved, for a child's creed tends to resemble that of its parents - but there is more to divine heredity than that. Identical twins are more likely each to be believers, or non-believers, than are non-identicals, and the similarity between them is greater in adulthood than in adolescence.
That evidence is indirect, but now the biochemists - and the drug companies - are getting in on the act. Serotonin's machinery is complex indeed, but a certain receptor for the substance on the surface of brain cells plays a key part.
When it comes to real Ecstasy (the drug that interferes with serotonin pathways, rather than the mystical state of mind), rats, like teenagers, tend to snuggle up to strangers in a blissed-out way after a couple of tablets. Block the receptor and they return to their solitary selves, as further proof of the molecule's effects on the mental process.
Different individuals have very different numbers of copies of that binding protein. Mice with few copies are more anxious than others (they produce more droppings when they cross an open space - not, perhaps, a good model for human behaviour) and those in which the gene has been knocked out altogether seem to worry all the time.
Even worse, they do not respond to Prozac, which calms down their normal brethren. People with panic disorders or depression, too, are short of the magical molecule.
It has also been tied to schizophrenia (and lots of saints have shown symptoms of that). Now comes a claim that people with low levels of the receptor protein are more likely to turn to religion than are the rest of us. The effect is quite specific, for among the volunteers tested there was no fit across their four-fold range of receptor dose with any other element of personality, be it a tendency to act impulsively, to fear the unknown or to love company.
The molecular lock into which the serotonin key fits is, it seems, Beelzebub's own protein, for to inherit a decent dose of it is as good a vaccine against belief as was compulsory school assembly.
As so often in matters of dogma, the biology of faith is surrounded with doubt, but in today's atmosphere of sectarian conflict the new research might even be useful. In Tony Blair's planned universe of faith-based surveillance, perhaps a compulsory DNA check could pick up - or even lock up - people with the extremist gene. They might, on the other hand, just like St Teresa of Avila, use it to justify their behaviour.
* Steve Jones is professor of genetics at University College London
Religion | By doctormatt | 6:15 AM