With the politics of behaviour in the ascendancy, there is increasing interest in what science can tell us about why people behave the way they do. The British government is funding the creation of the National Academy for Parenting Practitioners, with the express aim of training a 'parenting workforce' to provide science-based child-rearing advice to parents. In the USA, the MRI scanner and the neuroscientific community are entering the court room to give evidence about whether defendants can be regarded as being responsible for their alleged crimes. UK policymakers cite scientific 'evidence' to explain new interventions on everything from early years' education to the alleged impact of school dinners on academic performance. The science of nutrition now informs earnest discussions about how children's diets improve their classroom behaviour, in order to justify policing lunchboxes and putting school meals at the top of the political agenda. Studies of teenage brain development now regularly inform social debates about the impact of new technologies on young people.

But how much can science tell us about behaviour? Do scientific findings justify the government's many interventions into the early years of children's lives? Should neuroscience enjoy an exalted place in the courtroom? Are policies being developed because of genuine advances in scientific knowledge - or is science being (mis)used, perhaps in the place of political conviction, to justify policies?