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For years, policymakers have relied on “nudges” – subtle interventions that encourage people to make better choices without restricting their freedom. From making green energy the default option to placing healthier foods at eye level in grocery stores, nudges aim to shape everyday decisions. 

A new study, , led by Dr Aba Szollosi, Lecturer at the �鶹��madou Institute for Climate Risk & Response, and co-authored with Institute Director Professor Ben Newell and Dr Nathan Wang-Ly, Director of Behavioural Science at ANZ Bank, challenges the dominant thinking behind this concept. 

The study finds that while  traditionally has emphasised the idea that people are "lazy, capacity-limited, and largely unaware of the reasons underlying their behaviour" who need to be subtly pushed (or "nudged") toward better choices, this view is outdated. Instead, after carefully analysing the available literature, Dr Szollosi and his co-authors find that  who make decisions based on their understanding of the world and what matters to them.

Dr Szollosi said: “Existing explanations for how behaviour change works rely on shaky foundations – suggesting that we need to exploit people’s inborn biases and their powerful unconscious if we want them to make better decisions. 

“These factors have been shown to influence behaviour to a much smaller extent than previously thought, and so our paper aims to outline an alternative framework for how subtle changes to the choice environment – nudges – can work.”

Why nudges fail: the importance of cognitive and motivational alignment

In 2015, the Obama administration put the concept of nudging to the test by creating the , which applied behavioural insights to public policy. By tweaking default settings and simplifying processes, they increased retirement savings and college enrollment – showing that small choice shifts can influence behaviour. 

But nudging isn’t always effective at changing behaviour, especially when other, more systemic factors and motivations are at play. In April 2022, the UK government mandated that large food businesses display calorie information on menus to encourage healthier eating habits. However, subsequent that this intervention led to only a – about 11 calories per meal, equivalent to two almonds. This minimal impact suggests that while nudging through calorie labelling provides information, it may not be sufficient to drive significant behaviour change in addressing complex issues like obesity. 

According to Dr Szollosi, if a nudge is meant to encourage action – like reducing carbon footprints – it will only work if there is:

• Cognitive alignment: the person understands the underlying problem (e.g., they believe climate change is real).

• Motivational alignment: the person actually cares enough to act (e.g., they prioritise sustainability over convenience).

If either of these is missing, the nudge is unlikely to work. For example, putting energy-saving tips on bills won’t change behaviour if someone doesn’t believe climate change is a problem or doesn’t feel personally responsible for fixing it. This is because we all have biases that affect all aspects of our lives and those of others we interact with. 

Professor Newell explained: "This is because we all bring different perspectives to the decisions that affect all aspects of our lives and those of others we interact with."

Dr Szollosi added: “Behaviour change interventions often aim to get people to make different – ostensibly better – choices (regarding their finances, health behaviours, environmental behaviours, etc). 

“We argue that the extent to which an intervention is successful depends on how good it is at making people agree that 1) the choice is important and 2) the recommended choice is actually better than the one they would’ve picked otherwise. This runs counter to the currently popular view.”

Moving beyond nudges to influence behaviour 

The paper suggests that, for example, if governments set green energy as the default option, they might increase some uptake, but without understanding why people may want to opt-out (or into) a green energy default, we won't be able to drive widespread, lasting change.

So, instead of assuming people are mindless decision-makers, the study suggests that effective policies should engage people’s thinking. Specifically, this means:

• Providing clear, credible information rather than just tweaking choices.

• Understanding why people act the way they do before designing interventions.

• Recognising that some people may resist nudges if they conflict with their beliefs or priorities.

Dr Szollosi said: “Climate change is one of the main decision contexts that nudge research targets. Understanding what drives behaviour change better can help us find better ways to increase behaviours aimed at combating it.”

The researchers also warn against relying too heavily on past studies showing that nudges work, as many suffer from publication bias (only reporting successful cases). Instead, they argue for a smarter approach that treats people as engaged thinkers, not passive decision-makers.

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