Nudge: it’s not science, it’s ideology

The latest fad among policy-makers is using “nudges” to gently push people in the right direction. Unsurprisingly, David Cameron is a big fan of this approach, while the Telegraph are preposterously terrified of sinister nannies perpetrating mind control. In a battle between the Telegraph and David Cameron, it is difficult to choose a side. In fact, they are both wrong.

Nudge theory was put forward in the book Nudge: Improving Decisions About Health, Wealth And Happiness in 2009. It is, ostensibly, a book about behaviour change and psychology, and has been heralded as a scientific panacea for developing policy–changing risky behaviour such as smoking and alcohol consumption would lead to fewer deaths, after all.

The book was written by a lawyer and an economist. This is the first alarm bell: neither of these professions are known for their training in human behaviour. To Nudge’s credit, though, at least the authors acknowledge that economic theories have it all wrong about human behaviour: traditional economic models tend to start with the rather flawed assumption that people are completely rational. Nudge instead focuses on the social and environmental context of behaviour and the cognitive shortcuts we use while processing the world around us.

I discussed Nudge’s views on the context of behaviour and how our brains rarely think unless we absolutely have to in more detail in this post on default options, where I opened with the statement that Nudge is the worst book on behaviour change ever written. I stand by this thesis. Here is why.

There are several concepts which are important to nudge theory. The authors propose that decisions take place within a “choice architecture”, that is, the context of the behaviour. They also propose that there are two systems for making decisions: the automatic system and the reflective system. The former is unthinking, unconscious. The latter is rational. There is nothing inherently wrong with these ideas: it is nothing that surprises those in psychology or the field of behaviour change, and it is nothing that has not been extensively researched before. This book, in fact, provides a  overview of these concepts, among others, which influence health behaviour, and synthesises them into a comprehensive theory. It was published several years before Nudge and is not referenced.

In fact, given the depth of understanding of automatic processes, one might suspect that the authors’ research was a quick glance at Wikipedia’s list of cognitive biases.

The framework proposed by the authors to change behaviour is termed “libertarian paternalism”. Both words are enough to set my teeth on edge, and in oxymoronic combination my blood pressure shoots through the roof. In short, libertarian paternalism involves policymakers doing as little as possible–for example, smoking bans are verboten–hoping people will choose to perform the desired behaviour. Policymakers are expected to nudge people in the right direction.

What is a nudge? The authors provide a handy acronym for their proposed methods for changing behaviour. It is rather fudged. Nudges are:

• iNcentives
• Understand mappings
• Defaults
• Give feedback
• Expect error
• Structure complex choices

This translates to various simple, minimal-intervention methods, such as simplifying forms, feedback, providing information in a readable format or modifying default options.

It really is that simple, according to the authors.So simple, that most of the book is dedicated to presenting a series of nudges and things they think could work as a nudge.

To the untrained eye, it appears that Nudge is scientific and evidence-based. There are a lot of references and citations, after all. Surely that must mean it is science?

Not at all. The evidence presented seems cherry-picked. It is likely that this was not undertaken with duplicity, but rather with ignorance. For example, the authors cite a smoking cessation trial in the Philippines which used a method they deemed as nudging. They claimed great success for this intervention–in fact, the trial and analysis were undertaken poorly with a small effect. This happened in a number of places where the authors presented “trial” data; the authors do not seem to understand how best to test that an intervention works.*

In fact, Nudge presents no evidence that nudges would work better than something that was not a nudge. Again, this is likely to be due to the authors’ lack of training in the behavioural sciences. The way to test this would be to conduct a randomised controlled trial. In short, one would randomly allocate a large number of people to be exposed to a nudge, with an equivalent number of people randomly allocated to not receive the nudge. One would then see how many people from each group changed their behaviour. It is quite a simple concept, and seems to have escaped the authors’ knowledge. Instead, they repeatedly trumpet nudges to be effective with no supporting evidence.

Nudge further neglects an important aspect of behaviour change: helping people gain the skills to change their behaviour. It is no good nudging people to buy healthy food by improving labelling if they are not taught how to cook a healthy meal. It is no good providing people with nicotine patches to help them stop smoking if they are not taught how to cope with psychological cravings. Skill-training is important, and there is rather a large evidence base on the importance of training and improving self-regulatory capacity.

There is also a rather large body of evidence to suggest that higher-intensity interventions are much more effective at changing behaviour than those with less contact. So, for example, sitting down with someone and helping them write a plan about how they are going to stop smoking is better than giving them a leaflet and letting them write down how they plan to stop smoking. Nudges are inherently minimal-intervention and thus would be unlikely to be particularly effective.

Useful, perhaps, but not sufficient.

Beyond the distinct lack of evidence to back up the theory, Nudge runs into another enormous problem: even its authors acknowledge that nudges work best for well-educated Western people. This means that in using nudges, whole groups of disadvantaged people miss out on help in changing their behaviour. This seems par for the course with our current government. No wonder David Cameron likes his nudges.

Overall, though, one of the largest problems with Nudge is that after reading the entire bloody book, I was still none the wiser as to what a nudge is. The authors provide numerous examples and a rather fudged acronym, but there is still the sense that a nudge is essentially something that the authors like. As conceptualised, there is no real reason that a smoking ban should not be a nudge–it is, after all, environmental modification to disincentivise smoking. The only reason a smoking ban is not considered a nudge is because the authors say it isn’t.

Despite all of this, and following an evidence inquiry at the House of Lords, an expensive “nudge unit” has been set up and one of Nudge‘s authors called in to advise on policy.

Nudge is not science. Nudge is not a panacea towards behaviour change. It is libertarian, laissez-faire ideology formatted readably.

Nudge is not a road-map. It is a childishly-scrawled drawing of a street scene.