The saving to society might be as much as a hundredfold.Professor Bateson is Provost of King’s College, Cambridge.. Last weekend, a backbench Tory who has been a close friend of Kenneth Clarke since the early 1970s telephoned the Chancellor. The cost of providing help for the children was not great, whereas the cost of incarcerating an adult in jail is enormous. 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. 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.

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. 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. 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.

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. 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. 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. 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. 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.