Who’s afraid of genetic determinism?

The modern science of evolutionary psychology is a child of the Enlightenment, developing the 18th century concept of ‘human nature’ but adding vital insights from later centuries. From the 19th, it takes Charles Darwin’s notion of evolution and asks how human behaviour, and the thoughts and emotions that lie behind it, have been shaped by natural selection. Mendel’s genetics are incorporated too — the idea that particular behaviours or ways of thinking are influenced by particular genes. From the 20th century, evolutionary psychology borrows two great refinements of Darwin’s ideas: John von Neumann’s game theory, which enables us to quantify the efficacy of any particular behavioural strategy, and the insight that emanates mainly from Professor Bill Hamilton, which says that natural selection operates primarily on individual genes (including genes that influence behaviour) rather than on whole organisms or (still less) on groups. Because evolutionary psychology is concerned with the way that human beings behave, it bridges the perceived gap between the sciences and ‘the humanities’. Already there is a fine flow of ideas between evolutionary psychology, economics, and literature. It promises to be one of the most fruitful pursuits of the century to come.

Yet no subject arouses more opprobrium. In newspapers and on radio, otherwise affable commentators spit blood when anyone mentions Darwin in the context of human behaviour or emotion. Britain’s ‘arts — science’ divide is partly to blame, for ‘arts-trained’ people hate to think that scientists should presume to offer thoughts on the human mind. But some biologists are just as antagonistic, notably Stephen Jay Gould and Steven Rose, who accuse evolutionary psychologists of ‘genetic determinism’ which (so Rose suggests) is one small step from Nazism. ‘Genetic determinism’ sounds truly chilling. It implies that if particular aspects of our behaviour are underpinned by particular genes, then our whole behaviour must be driven by a genetic ‘programme’, and that we are merely puppets, acting out our genes’ directives. Fine ennobling concepts like ‘free will’ and personal responsibility seem to go out of the window.

But the idea of ‘genetic determinism’ is mere rhetoric. For a start, no evolutionary psychologist doubts that a gene is in constant dialogue with its surroundings, which include the other genes in the genome, the rest of the organism, and the world at large. Thus, Roslin Institute, creators of Dolly, have produced a clone of four young rams called Cedric, Cecil, Cyril, and Tuppence; although these four are genomically identical, they are in all observable ways quite different. Cedric is a big bullying fellow, while Tuppence is small and timid, with the other two in between. They developed in different wombs, and look at the world through different eyes, and this makes them distinct, whatever their DNA may say.

Then again, genes that influence the behaviour of mammals do not tell their owner, ‘Do this’, or ‘Do that’. They provide algorithms, whose advice is provisional: ‘If A happens, then respond with X; if B, then do Y’. Our behaviour is not ‘determined’: merely predisposed. Yet we should know what our predispositions are, and the ways and conditions in which they become manifest.

To be sure, evolutionary psychologists sometimes speak of particular genes coding for particular items of behaviour; this is an unfortunate expression, but it is only shorthand, and not to be taken literally. Thus, one favoured hypothesis holds that the brain function is modular — like a metaphorical Swiss army knife, with modules that help us to read or to recognise faces, and so on. There is nothing outrageous in this: no one has ever doubted that individual people (or human beings in general) tend to be good at some things, and less good at others. Many genes may cooperate to form any one module. But — as is common in Mendelian genetics — we notice that the module exists only when one or other of the contributing genes is not functioning properly. Thus, particular mutant genes seem to contribute to dyslexia, and sometimes people speak too casually of genes for dyslexia. All that this implies is that normal versions of the ‘dyslexia genes’ contribute to the modules that promote the skill of reading, and that defects in those genes compromise the ability. To say there are genes ‘for’ particular behaviours is sloppy perhaps, but it is not the naive or sinister concept that some critics suppose.

Finally, as the adage has it, ‘Genes make brains’. Insect brains are slavish, but in humans and other bright mammals, natural and sexual selection have pursued a mixed strategy. On the one hand, they have favoured quick-and-simple responses with survival value (run from lions and trust people who smile), and on the other they favoured variety of response, which requires a complicated brain capable of thought. The idea that we think and indeed are creative is perfectly compatible with the notion that our brains have been shaped by natural and sexual selection. By the same token, it would be very hard to dispense with the notion of free will, even if we wanted to.

So where, in the whole discipline of evolutionary psychology, is the notion of ‘genetic determinism’? By contrast, as Christopher Badcock of LSE points out, the politically correct notion that human beings are a tabula rasa, with protean brains that can be shaped ad lib by environment, has become the most potent agent of oppression, as in Stalin’s Russia and Pol Pot’s Cambodia. These regimes proved, if proof were needed, that human beings are not infinitely flexible, and are very unhappy when forced to act out of character.

We need to know what our character is, not to make regimes that copy ‘nature’ (for ‘is’ is not ‘ought to be’) but to shape societies in which we feel comfortable, and which play to our strengths. This is a necessary and humane pursuit, and future generations will surely condemn those who are now misrepresenting it.

Colin Tudge’s latest book, Neanderthals, Bandits, and Farmers is available from Weidenfeld & Nicolson at £4.99

(Reprinted from Biologist, the journal of the Institute of Biology, with permission.)