This is a book that has caused something of a stir over the last year or so. In particular, the leader of UK Conservative party, David Cameron, is reportedly very interested in the ideas the book presents. Likewise, the Obama administration seems ready to take up the idea of ‘nudge’, and one of the authors, Sunstein, has just been appointed as head of White House office of Information and Regulatory Affairs. The idea of ‘nudge’ is therefore something we ought to take seriously.

But how seriously can we take it? In particular, what can we make of an idea that is built on a deliberate oxymoron, namely, the concept of ‘libertarian paternalism’? Have Thaler and Sunstein come up with something new and original, or is the appeal of ‘nudge’ precisely that it gives legitimacy to what politicians like Cameron and Obama wish to do anyway?

The book is clearly aimed at the general reader as well as academics and policy makers. It makes no great demands on its readers, being written in that rather informal and chatty style favoured by American authors when they are trying to reach beyond a purely academic audience. The book is divided into five parts, of which the first defines the idea of nudge itself. The authors are critical of policies built on straightforward economic incentives, and they take issue with what has become known as ‘efficient economy’ model. Instead, they use recent work in behaviour economics and psychology to build a more nuanced picture of human behaviour. Having established the core concept of ‘nudge’, Parts 2–4 provide examples of how what the authors call ‘choice architects’ can nudge individuals to take ‘better’ decisions, such as eating more healthily, saving more for their retirement, investing better, being more environmentally friendly and so on. The final part of the book considers some of the possible objections to the idea.

Central to the idea of ‘nudge’ is what the authors term ‘libertarian paternalism’ (p. 4). This is clearly taken to be an important concept, but it is defined only briefly and without any reference to key thinkers other than a passing mention of Milton Friedman. All they say is that the ‘libertarian aspect of our strategies lies in the straightforward insistence that, in general, people should be free to do what they like – and to opt out of undesirable arrangements if they want to do so’ (p. 5). Their core aim here is to be ‘liberty preserving’ (p. 5). In terms of paternalism: it is ‘legitimate for choice architects to try to influence people's behaviour in order to make their lives longer, healthier, and better’ (p. 5). This involves steering peoples' choices, and accordingly they claim that a ‘policy is “paternalistic” if it tries to influence choices in a way that will make choosers better off, as judged by themselves’ (p. 5, original emphasis). The authors make no further attempt to defend this concept, but instead seem to rely on a common sense understanding that libertarianism equals choice and paternalism equates to the judgement of experts.

The idea clearly relates to the choice agenda that has dominated policy making in the UK. The authors talk of ‘choice architects’, who they see as those who are able to nudge individuals towards certain sorts of behaviour through judicious policy frameworks. This involves providing the right sort of incentives and by creating the most benign ‘default position’. We might argue, therefore, that all Thaler and Sunstein are doing is describing what politicians in Europe and the USA are already doing. Aware of resistance from their electorate to higher taxes, politicians seek to use indirect methods to achieve their aims, be it on climate change, or retirement insurance.

Linked to this is the obvious manner in which the concept of nudge can appeal to both left and right at the same time. The left can pick on the paternalism and the idea that it is legitimate to incentivise certain forms of behaviour and punish other forms; the right might focus more on freedom and choice. We might see this as another attempt to reconcile or move beyond a traditional left/right division, much as Blair and Clinton's ‘Third Way’ attempted in the late 1990s. But, it might also be a fudge that seeks to include all arguments and exclude nothing.

But how useful might the idea of ‘nudge’ be? It might be very useful precisely because it seeks to offend no one, and so might be a politically acceptable means of proceeding: how can anyone object when we have taken the decisions ourselves? But there are two readily apparent problems with the idea of ‘nudge’ that might limit its usefulness.

First, this approach can only ever be piecemeal. Nudging people means that any change will be incremental and slow. This suggests that we might not be able to use it in all cases, especially those where immediate and urgent action is required. Second, as it relies on people making choices, we might object that people can only be nudged in a direction they wish to go. They cannot be forced into a completely new direction. Of course, we might respond that this is precisely what we would want in a democratic society.

Finally, there is a problem with the structure of the book. The core argument is established in Part 1 and the authors provide a clear position. However, Parts 2 to 4, which provide examples of how people can be nudged, are somewhat repetitive, with the core ideas being continually returned to. Perhaps the authors were worried that some readers might only focus on the policy area that most interested them. However, this makes for a rather dull read for those reading the book from cover to cover.