Natural gold dust

Nobody who has even the slightest passing acquaintance with modern science still asks that nonsensical old question about "nature versus nurture". We know that nature and nurture both play an important role in our development. We are all interactionists now.

This has been a common theme in popular-science writing recently. Patrick Bateson and Paul Martin explored it brilliantly in their book, Design for a Life. More recently, Steven Pinker went over the arguments again in The Blank Slate (2002). And now science writer Matt Ridley has pitched in with another analysis of the debate.

The conclusions he comes to are broadly the same as those of his forerunners. Nature and nurture act together in complex ways so that it is more accurate to talk of nature via nurture (a nifty phrase that Ridley borrows from David Lykken) than nature versus nurture. So what's new?

The novelty of this book lies in the details rather than in the wellworn claim that constitutes its central thesis. Ridley reports many of the intriguing findings which have emerged in recent years from human genetics.

Whether describing the way that a single point mutation in a gene on chromosome 11 affects how neurotic you are, or discussing the role of celladhesion proteins in wiring up the developing brain, these snippets from the cutting edge of biology are the real meat of the book, and they allow Ridley to display his obvious talent for combining clarity, concision and accuracy.

The organisation of these details into a coherent whole is less satisfying. They are stitched together into a single narrative by means of an "imaginary photograph", which Ridley conjures up in the prologue. The photograph Ridley dreams of shows a group of 12 men gathered at some international meeting in 1903.

Among the group are Francis Galton, Ivan Pavlov, Sigmund Freud and Darwin (or rather, his ghost, since Darwin was dead by then). Ridley intends his imaginary photo to be a psychobiological equivalent of the group photo of Einstein and other leading physicists taken at the Solvay Conference in 1927.

Just as the scientists gathered there pioneered modern physics, the men at Ridley's imaginary meeting laid the foundations of our current understanding of human nature.

Unlike the physicists, most of these men never met, though if they had it is hard to imagine them getting on well enough to pose for a joint photo; these men held such different opinions about human nature that their exchanges would surely have made the spats between Einstein and Niels Bohr look relatively benign.

In view of the widely differing views proposed by the men in the imaginary photo, it is a bold move to claim, as Ridley does, that all of them were right, in the sense that "they all contributed an original idea with a grain of truth in it".