The perils of genetic determinism

Searching for the gene that causes criminality is a waste of time and money, argues Patrick Bateson

This week a meeting was held in London on the genetic influences on crime. A number of scientists, including myself, felt that the organisers had not tried very hard to produce a balanced programme on such a potentially explosive issue.

Doubtless they wanted a strong and coherent message to emerge from their meeting. Sequencing of the human genome attracts so much funding that it would be surprising if a few of those in the behavioural sciences were not interested in some of that gravy.

What is more, members of the public are frightened by the crime statistics and the Home Office would like someone to come up with a quick fix. A drug that would silence the gene for football hooliganism (I joke) may be a gleam in the eye of some pharmaceutical company.

Predictably, the meeting produced headlines like "Biological make-up may hold key to criminal behaviour" (the Times, 14 February). In the same week, and much more plausibly, the crime wave was blamed on high unemployment. The sad thing was the determinism that accompanied the media coverage of the claims. It was obvious that, in certain quarters, the dreadful old nature-nurture debate was rampant once again.

By contrast, the Independent leader on 13 February pointed out calmly: "The determinants of human behaviour are likely to be a complicated mixture of environmental factors and perhaps a mlange of various genetic influences." Yes, indeed. So why aren't others so reasonable? Why do they ask whether differences in genes will provide the key to explaining differences in the way in which people behave?

Part of the trouble, I suspect, is that everybody knows about the genetic code and supposes that having a code means a one-to-one correspondence between genes and behaviour patterns.

The mistake arises because the coding occurs only at a very early stage in the whole process. Genes code for a sequence of amino acids used to build proteins. These products of gene expression combine with various substances in the cells of the body to form in different ways the separate parts of the developing nervous system. The ways in which they do so are influenced strongly by the local conditions in which the young individual is developing.

These effects may be striking. The plague locust that developed in crowded conditions was regarded incorrectly as a separate species from the non- migratory form, which developed solitarily.

By degrees, both sides in the nature/nurture dispute have come to appreciate that behavioural development cannot be treated as though it were wholly under the control of the genes or wholly influenced by the environment.

Dispositions to respond strongly to some features of the environment often develop without direct experience of those features, and stereotyped motor patterns often develop without obvious opportunities for practice. The human baby smiles at about four weeks after birth but does so even when the baby is blind.

Even so, such aspects of a behavioural repertoire, once developed, may be modified by experience; indeed, people adopt the smiles that are characteristic of their culture. If some people possess genes that predispose to violence, are they more likely to behave violently than others without such genes, irrespective of the conditions in which they grew up? If they grew up in an especially psychopathic culture, are they more likely to behave dangerously, irrespective of their temperament?

In the absence of evidence, your response to these questions will depend on whether you adopt what might be called a muesli view of behavioural development. On such a view, you will suppose that the origins are all easily recognisable in the final product as the behavioural equivalent of raisins, nuts and oats.

An alternative to simply slinging the ingredients together is to cook them. As in baking, the flour, eggs, butter and other ingredients react together to form a product that is different from the sum of the parts. The actions of adding ingredients, preparing the mixture and baking all contribute to the final effect. You would not expect to recognise each ingredient and each action involved in cooking as a separate component in the finished cake.

Like all analogies, likening behavioural development to cooking has its limitations. The cake is passive whereas the developing animal is equipped with a set of rules for dealing with the world, one or more opening moves, and some conditional instructions about what must be done in particular circumstances.

I study animals that are much, much simpler than humans. Yet what they do is pretty impressive. Just after hatching, ducklings will work to present themselves with objects whose details they will learn. They choose environments that match their own capabilities and characteristics. The outcome of events of a moment ago becomes part of the conditions that control behaviour now.

The development of individuals is an interplay between them and their environment. Individuals choose and change the conditions to which they are exposed; then they are themselves changed by those conditions.

The prescription that all we have to do is locate the single, genetic cause of criminal behaviour and then get rid of it simply does not seem plausible. For that reason I am not especially worried about the implications of the genetic analysis to criminal behaviour because I doubt very much whether it could ever be very effective on its own. It could waste a great deal of money, however.

Much more useful are those programmes that were designed to improve the social and educational environment of deprived children in the United States. They may not have done much to boost intelligence, as was hoped for at the time, but they had remarkable effects later in life.

Unlike their contemporaries who did not enter the programmes, these children did not settle into crime or spend a large part of their subsequent lives in prison. The cost of providing help for the children was not great, whereas the cost of incarcerating an adult in jail is enormous. The saving to society might be as much as a hundredfold.

Professor Bateson is Provost of King's College, Cambridge.