Writing on the wall for nature?

Michael Rutter finds a well-known science populariser unscientific.

What a strange mixture this is. In many ways The Blank Slate is fundamentally silly, despite the deservedly high academic standing of its author, Steven Pinker. Both the title of the book and its rationale, as set out in the text, presuppose that most researchers believe that the mind is a "blank slate", unaffected by genetic influences, with the whole of psychological development shaped entirely by patterns of rearing. That is simply nonsense. Of course, it is possible to find individuals who hold such a ridiculous view, just as it is possible to find individuals who support extreme genetic determinism. However, neither view is typical, as is obvious from looking at the leading British texts on psychology, psychiatry or child psychiatry in the past half-century. The blank-slate position has also not been characteristic of most leading researchers in the field of child development on either side of the Atlantic (see, for example, the writings of Judy Dunn, Anne and Alan Clarke, Rudolph Schaffer and Robert Hinde in the UK, and Eleanor Maccoby, Steve Suomi, Jerry Kagan, Terrie Moffitt, Stella Chess and Leon Eisenberg in the US - to mention just a few). Yet Pinker persists with his accusation that there is "a contempt among many scholars for the concepts of truth, logic and evidence"; that "the denial of human nature has not just corrupted the world of critics and intellectuals but has done harm to the lives of real people", with "in almost every instance, the most extreme position - that parents are everything - the only one researchers entertain".

Despite its scholarly cloak, this is tabloid evangelism. Pinker claims that authors who invoke nurture and nature have been assaulted or threatened with criminal prosecution - giving Arthur Jensen, Philippe Rushton and Hans Eysenck as examples. It is true that some people resorted to behaviour that was illiberal, unseemly and offensive in protesting at views that were interpreted as racist. But Pinker has chosen to ignore the much more measured (but severely critical) scientific assessments of the work of such individuals. Throughout the book there is heavy reliance on unpublished papers and media reports of interviews with researchers and others, as well as an uncritical acceptance of unreplicated findings. The book provides a reasonable critique of the absurdity of the blank-slate view, but it gives a most misleading portrayal of the extent to which it is held. Pinker is at pains to point out that both nature and nurture have effects, but the arguments put forward in the book are almost entirely on the role of nature. There is no systematic discussion of the evidence on environmental influences, still less on how such influences might operate.

Because of this intemperate style, in which almost everyone, apart from evolutionary psychologists and biologists, is sweepingly castigated, the book gets off to a bad start. However, it is worth persisting with. Not for nothing is Pinker widely respected as an academic scholar and original thinker, as well as a persuasive and highly skilled populariser of science. Even the first part of the book is most engagingly written and it includes some considered critical reviews of topics such as connectionism and neural plasticity.

Connectionism is, as Pinker puts it, the theory that the brain is like the artificial neural networks simulated on computers to learn statistical patterns. This theory has been quite influential and neural-network modelling is an important research strategy. Connectionists do not espouse a blank-slate view, but Pinker argues that, on occasions, their belief in a general purpose learning device seems to ignore the innate basis of the wiring of the network. He argues that, properly considered, neural network modelling should bridge the gap between the elementary steps of cognition and the physiological activities of the brain, thus providing an important link in the long chain of explanation between biology and culture.

Pinker's approach to neural plasticity is similarly critical but integratory. He emphasises the probabilistic nature of brain development and notes the role of experience in its sculpting and shaping. But, rightly, he pours scorn on the notion that experiences determine the whole of brain development. Pinker's critique is incisive and on target, but he is less successful in describing just what developmental programming might involve, and which aspects of brain development or which kinds of experiences are involved. What he terms "the ghost in the machine" gets short shrift, but it is regrettable that he does not do more to put something more constructive in its place.

The third part of the book, "Human nature with a human face", aims to dispel people's fears in relation to the supposedly socially damaging effects of the concepts of inequality, imperfectibility, determinism and nihilism. Clearly, Pinker is right in differentiating between biological facts and human values. Manifestly, there are important individual differences with respect to all traits and it would be absurd to suppose that psychological features constitute an exception. He draws close parallels between Marxists and Nazis in their emphasis of inter-group hostilities, albeit on the basis of contrasting ideologies. However, the blank slate is specifically held to blame for some of the particular evils of Marxism.

The dread of a permanently wicked human nature is dealt with along similar lines. There is skilful debating swordplay to dispose of the notion, for example, that there are no biological differences between boys and girls (apart from their genitals) and that gender identification is malleable, but there is a strong whiff of straw men about this onslaught. Determinism is attacked rightly on the grounds that explanation and exculpation should not be confused. Pinker points out the parallels between genetic and environmental determinism and the fallacy of supposing that causal explanations necessarily erode responsibility. The final fear of biological explanations of the mind is that they strip our lives of meaning and purpose. Pinker counters that a moral sense is part of the standard biological equipment of the human mind.

The key message of this middle section of the book is that human nature does not undermine humane values. Most people would readily accept that this is so, but the arguments that Pinker puts forward are primarily ethical rather than scientific.

The fourth section attempts to deal with the nature of human nature and the difference it makes to our lives. Given that it is the author's main area of expertise, it is appropriate that he provides a thoughtful and well-informed discussion of language and its role in thinking. Nothing very controversial here, but in the next chapter, after a sideswipe at traditional education based on a blank-slate notion that schooling is designed to deposit knowledge that can be reproduced later in tests, Pinker uses the notion of "theory of mind" as a launching pad for a discussion of the soul and the decision of "when life begins". Unafraid, he discusses cloning, animal rights, abortion and genetically modified food, passes on to the topic of the reckoning of probabilities and the contrast between equality matching and market pricing as approaches to economics. The territory covered is very wide and, inevitably, much is dealt with rather superficially, although Pinker is never dull and much of what he writes is thought provoking. The same applies to the chapters that follow on the selfish gene and sociobiology, inveterate psychopaths versus conditioned psychopaths, rationalisation versus self-deception, and on gut feeling and moral judgements.

"Hot buttons", the fifth section of the book, is so called because it deals with the emotive issues of politics, violence, gender, children and the arts. Pinker argues for a bringing together of what he calls the tragic and utopian visions - under, of course, the banner of Darwinism. His discussion of violence is thoughtful and mostly balanced, but its reasonableness comes from Pinker's own humane approach rather than from scientific evidence. He has a neat way of summarising major issues under catchy headings that do much to capture the essence of the arguments - as, for example, in the contrast between what he calls gender feminism (which denies biological differences) and equity feminism, which is a moral doctrine about equal treatment.

The chapter curiously titled "Children" comprises a generally fair summary of behavioural genetics that emphasises both the range of ways that genes operate and the possible role of chance. However, Pinker misunderstands the meaning of the distinction between shared and non-shared environmental effects, and his discussion of peer-influences theory is uncritical. The last sentence of the chapter returns to the supposed belief that children are blank slates rather than people.

Having provided us with some entertaining, urbane and scholarly discussions on a range of important topics, Pinker ends the book by blaming the blank slate for the adverse effects of modernism and postmodernism on the elite arts and humanities, bringing about their decline and fall. Oh dear! He then concludes that the blank slate is an anti-life, anti-human theoretical abstraction that denies our common humanity.

What should one make of this curious book? That it is a good read is undeniable and, equally, there is much to admire in the breadth of Pinker's intellectual vision and incisive discussion of some really important issues. It is not science, however, and it is spoiled by his preoccupation with a conviction that blank-slate views remain the norm.

Sir Michael Rutter is professor of developmental psychopathology, Institute of Psychiatry, London.