Nudge behaviour change – Is it real?

Nudge behaviour change – Is it real?

Nudge behaviour

The book, ‘Nudge: Improving Decisions About Health, Wealth, and Happiness’

In 2008 Richard Thaler and Cass Sunstein published a book that created a whole new industry in behaviour change. The book, ‘Nudge: Improving Decisions About Health, Wealth, and Happiness’ starts with the premise that paternalism, or the idea that experts with authority do often know best and make better decisions than uninformed individuals, especially in terms of what is better for our health, wealth and happiness. Thaler and Sunstein challenges what they call the ‘dogmatic anti-paternalism’ of a too liberal policy of self-determination. The book challenges the ideas that:

  1. Paternalism has to be coercive
  2. Paternalism is avoidable
  3. People make better choices than the paternalists or experts in authority

In the book, Thaler and Sunstein argue for a form of what they call “libertarian paternalism” and that paternalistic experts usually both have a wider evidence base and tend to know what works and doesn’t work better than the individual, who left to their own devices continually make decisions counter to their own well-being.

One of the examples in the book…

One of the examples in the book is that of Carolyn, who Thaler and Sunstein refer to as a choice architect. Carolyn is manager of the university cafeteria and she understands how to ‘nudge’ people into making healthier choices at mealtimes. For example, she understands that by placing fruit rather than bars of chocolate in a bowl next to the checkout, in what is known as the ‘impulse basket’, , significantly more people are likely to eat fruit.

Nudge behaviour

A nudge

A nudge is defined by Thaler & Sunstein as “any aspect of the choice architecture that alters people’s behaviour in a predictable way without forbidding any options or significantly changing their economic incentives”.

The principles underlying choice architecture and nudge behaviour change

The principles underlying choice architecture and nudge behaviour change are that:

  1. Choice architecture, or how people are presented with choices, significantly impacts the choices they make.
  2. Choice architecture is unavoidable, in that we always arrive at a decision point through a process in which choices are naturally presented to us in certain ways and frames. Therefore, why not study the impact that choice presentation has on decision making, and make use of it, so that experts can help us make better, healthier decisions?
  3. Libertarian paternalism means that experts can nudge people towards better decisions without removing freedom of choice.

The book, and the core concept of choice architecture or nudging, has become an industry of its own.

A major review of research

However, in 2017 a major review of research conducted by researchers at the School of Biological and Chemical Science at Queen Mary University of London in the UK questioned the effectiveness of using choice architecture for behaviour change for noncommunicable diseases, such as heart diseases, stroke, cancer, diabetes and chronic lung diseases, which together are responsible for almost 70% of global deaths. All of these diseases are preventable through four main behavioural change factors:

  1. Smoking
  2. Physical inactivity
  3. Excess consumption of alcohol
  4. Unhealthy diets

The paper entitled “Nudge: concept, effectiveness, and ethics” published in the peer reviewed journal Basic and Applied Social Psychology, examined the research evidence for the success of choice architecture in nudging people into healthier choices and reducing these forms of disease. The review showed that there is little, if any, evidence that choice architecture is effective for behaviour change.

Publication bias

More recently, studies have questioned the extent to which publication bias has played a part in the rapid expansion in interest in using choice architecture for behaviour change purposes. Publication bias refers to a predisposition towards publishing studies that show a definitive finding, whilst ignoring research that is inconclusive. In essence, publication bias appears to be a natural form of confirmation bias that helps to decide which studies are published and which are rejected.

For example, a wide-ranging review of clinical research published in The Lancet by researchers from the Central Oxford Research Ethics Committee, University of Oxford in the UK, Johns Hopkins University School of Medicine and the University of Pennsylvania School of Medicine in the US found that studies with statistically significant results were more likely to be published than those finding no difference between the study groups by a ratio of 2-32.

This is even before reporter or researcher biases, which occur where researchers and reporters of research tend also to have a bias towards reporting or using research which confirms their views or their study (known as outcome reporting bias).

publication bias

A new study

A new study by a team of researchers from the Department of Experimental Psychology, University College London in the UK, the Department of Psychological Methods, University of Amsterdam in The Netherlands, Deakin Laboratory for the Meta-Analysis of Research and the Department of Economics at Deakin University, in Australia has used a new metanalytical method called Robust Bayesian Meta-analysis or RoBMA which can show heterogeneity, or diversity of content, and therefore predicting bias in things like publications.


The study found that when publication bias is taken into account, there is no evidence that choice architecture or employing nudges is an effective way to change people’s behaviour.

The bias towards the tendency for journals primarily to publish only positive or significant findings has so skewed the literature that when these (negative) results are added back into the evidence pool, the evidence that nudging leads to predictable and reliable behaviour change is no better than random chance.

Primary Reference

Maier, M., Bartoš, F., Stanley, T.D., Shanks, D.R., Harris, A.J.L. & Wagenmakers, E-J. (2022) No evidence for nudging after adjusting for publication bias. PNAS Vol. 119 | No. 31. Https://

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Disclaimer: This is a research review, expert interpretation and briefing. As such it contains other studies, expert comment and practitioner advice. It is not a copy of the original study – which is referenced. The original study should be consulted and referenced in all cases. This research briefing is for informational and educational purposes only. We do not accept any liability for the use to which this review and briefing is put or for it or the research accuracy, reliability or validity. This briefing as an original work in its own right and is copyright © Oxcognita LLC 2024. Any use made of this briefing is entirely at your own risk.

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