Books: Undressing for success

At the end of The Language Instinct, his 1994 bestseller, Steven Pinker jumped off the springboard. Having argued that language is a capacity made possible by a special organ of the mind, he offered his readers an exuberant shopping list of 15 other faculties for which evolution might also have engineered special mental machinery. They included instincts for mechanics, biology, contamination, justice and kinship, and a yen for habitats resembling savannah. Promulgating these 15 articles was a foolhardy act, he suggested; for some readers the list would be "the final proof that I have lost my mind". Now the MIT psychologist has published a popular treatise on how to find our minds, using clues dropped by how we think and act, entitled How the Mind Works (Allen Lane, pounds 25).

This time round, fewer readers will decide he has taken leave of his senses. In about as long as it takes to pass from fresher to graduate, evolutionary psychology has established a public profile and secured a place on the list of things a thinking person needs to think about. Some of its critics now treat it as more bad than mad. Last year, Pinker and Stephen Jay Gould exchanged words in the New York Review of Books after Gould published two articles in which he attacked "Darwinian fundamentalism" and described the evolutionary psychologists' enterprise as "fatuous".

Steve Jones used subtler tactics when reviewing How The Mind Works in the same magazine. Jones warmed to Pinker's style: both scholars relish anecdotes and colourful examples, such as the report Pinker relays that 62 per cent of toddlers were prepared to eat fake dog faeces made of peanut butter and smelly cheese. But Jones divided the book into two; an exposition of cognitive science, which he judged a success, and an attempt to explain human nature by natural selection. He called this "less persuasive", rather than fatuous. Jones appears to have opted for a strategy of containment.

In separating the two halves of the book, he removes its keystone. Pinker begins by dwelling on the truth that the images we perceive are not mirrors of the external world, but the products of highly complex computational processes. These computations structure our mental images in ways which we can recognise as highly distinctive, once we have used tricks such as optical illusions to allow us to see how we see. The second part of Pinker's thesis is that what is true of seeing is true of thinking. The mind as a whole works by computations, and comprises a system of mental organs adapted by natural selection to handle functions critical to reproductive success in the environments that shaped our species.

Pinker argues that only an adapted mind could do all the things that minds do. The alternative view, deriving from the British tradition and the compelling idea of the mind as a blank slate, a tabula rasa, is that a mind can derive all it needs from experience. Today, the so-called "connectionists" are modelling neural networks on computers in an attempt to explore how far this may be true. Pinker's view is that their efforts have only demonstrated that dedicated organs are necessary, on hard disks or in skulls.

Because it embraces both cognition and modern Darwinism, this book will become a landmark in popular science. We are unlikely to get a more readable treatment of such a broad landscape. But deep in these 660 pages, it is easy to miss the joins.

Pinker's sparky aphorisms are not always perfectly tuned. "Compared to the mind-bending ideas of modern science, religious beliefs are notable for their lack of imagination (God is a jealous man; heaven and hell are places; souls are people who have sprouted wings)." Tell that to young Christian children, trying to bend their minds around the idea of a God that is three beings in one, and of a soul which is within the body but has no physical existence.

At one point, he conspicuously loses the popular-cultural touch that usually serves him so well. "Women do not seek the sight of naked male strangers," he confidently asserts. Evolutionary psychology prefers theory to empiricism, and according to the theory: "It would make no sense for a woman to be easily aroused by the sight of a nude male. A fertile woman never has a shortage of willing sexual partners, and in that buyer's market she can seek the best husband available, the best genes, or other returns on her sexual favours. If she could be aroused by the sight of a naked man, men could induce her to have sex by exposing themselves and her bargaining position would be compromised." So evolutionary psychology must be right; the Chippendales, their squads of imitators, and the genre's legions of female fans must all be wrong.

Although it's not exactly a fatal flaw, this oversight illustrates several weaknesses which may impede the development of evolutionary psychology. This branch of modern Darwinism disturbs many people because they associate it with the political Right. The real political danger of evolutionary psychology is not that it is inherently conservative, however, but that it is normative. In attempting to delineate a universal human nature shaped by natural selection, it is apt to disregard phenomena which don't obviously fit. As its ideas percolate into the public domain, they may give a Darwinian slant to a view of the world in which men are expected to be men, and women to be women. Although some of the most interesting practitioners of evolutionary psychology are feminists, their perspectives are among the subtleties most likely to be lost as the discipline is popularised.

Within academe, the discipline's external relations are a touch contradictory. One of the most refreshing things about modern Darwinism is that it offers a common language that can bring together psychologists and archaeologists, economists and geneticists. But scholars such as the archaeologist Steven Mithen, whose groundbreaking book The Prehistory of the Mind appeared in 1996, sometimes express frustration that evolutionists do not appreciate the importance of other bodies of knowledge. Entranced by the power of modern Darwinian theory in its pure form, the evolutionists are too preoccupied to build the new synthesis that promises to emerge under Darwinian auspices.

It's questionable how much momentum they will be able to sustain without commitment to such a project. When Pinker overlooks the male-stripping craze, but notes that Playgirl doesn't contradict his argument because it is really a gay men's magazine, his mildly dated frame of reference symbolises the age of the research findings he describes. While evolutionary psychology has made great strides in the public domain over the past couple of years, Pinker and other leading lights have not matched this with equally exciting new ideas. In the case of male strippers, ethologists might be able to help devise a Darwinian explanation, in terms of what they would call female coalitionary behaviour.

Most of us still have plenty of catching up to do, though, and in this regard How The Mind Works is a major public asset. Above all, it delineates the most useful way of thinking about the mind. Yet this approach fails to address all the currently favourite conundrums. If you duplicated a human brain's activity on a computer, would the computer become conscious? Is your experience of red the same as mine? How do I know you aren't a zombie? "Beats the heck out of me!" Pinker gleefully cries. And that's as it should be. Natural selection did not put pressure on our ancestors to contemplate such questions. If God had meant us to do philosophy, he would have created us.