Behavioural public policy (BPP) applies behavioural insights to policy making. Emerging from the interest in nudges in the late 2000s, BPP has matured over the last decade and a half. An article in Policy and Society discusses the past, present, and future of behavioural public policy. It reflects on criticisms, the substantive achievements of nudge, the engagement of policy makers in nudge units and an emergent ethical concern illustrated by new tools, such as boost and nudge+.
Past: the origins and development of BPP
With its roots in behavioural economics and psychology, BPP rose to prominence over the past 15 years. There are several reasons for its rapid emergence. The applied nature of the field and public and political support for behavioural regulation came at an opportune economic and political moment. The book Nudge by Thaler and Sunstein was also a major catalyst, propelling its applications into the mainstream.
With behavioural units (also known an as nudge units) appearing in governments across the world, a track record of randomised controlled trials showed the potential for scaling up. Today’s behavioural interventions routinely occur in public agencies across most fields of public policy, ranging from tax compliance to environmental sustainability. While social marketing scholars and psychologists have been using behavioural interventions for decades, nothing compares with the scale and visibility of the nudge revolution that emerged since 2008.
Present: criticisms of nudge
Nudge was met with scepticism right from the outset and this discontent falls into three main themes.
1. Semantic challenges
One of the earliest challenges of nudging was the lack of conceptual clarity surrounding the term. As defined by Thaler and Sunstein (2008), a nudge refers to an intervention that neither bans options nor makes them economically costly. Instead, it influenced decision-making by presenting choices differently, aiming to help individuals make decisions they would deem beneficial if they were acting rationally.
The scope of nudges gradually expanded beyond the original definition to include interventions with limited predictability in their outcomes. For instance, information campaigns were often classified as nudges, despite failing to maintain an unchanged choice set—a key criterion for a nudge. This conceptual broadening has made it increasingly difficult to contextualise and compare nudges meaningfully.
2. Ethical challenges
A recurring critique of nudging has been the lack of transparency in its design and delivery. One of the earliest and most widely cited criticisms is that nudges are effective because they work in the dark.
This perceived lack of transparency often renders nudges covert and exposes them to allegations of manipulation. Nudges, by definition, should be easy to opt out of. However, ethicists argue that they can differentially affect individuals’ psychological capacities, making it difficult for some to recognise or resist them.
3. Efficacy challenges
The third critique of nudging concerns its variability in effectiveness. The challenge lies in the fact that many nudges fail to achieve the desired level of effectiveness as policy tools. This raises questions about their scalability. Another limitation is the lack of trials with a temporal design. Many behaviour changes require sustained intervention over time, yet most nudge studies rely on one-shot experiments. Additionally, as nudges become more widespread and long-term, individuals may adapt to them, reducing their effectiveness.
Future: the need for an alternative lens for BPP
The article outlines promising avenues for BPP which build on its strengths and address criticisms that have been made.
Reasonableness
Behavioural economics has relied on the notion that humans are “irrational” when they make choices. Hence the need for a nudge to move people toward welfare-improving choices. An alternative approach is to assume that people are and can be reasonable. This has the benefit that it treats individuals as targets of interventions, highlighting the need to involve and engage them. By putting citizens at the heart of behavioural public policy, reasonableness as an approach can build partnership with people.
Agency
Most behavioural interventions do not stress human agency. The question is whether some agency could be scaled into projects, especially ones needing long-term engagement of participants. This is a realistic possibility, with reflective interventions and feedback becoming normal parts of nudge interventions. Nudge+ could become the nudge of the future by being a common element in behavioural interventions.
Diversity and inclusion
Much of the early work on BPP has focused on evaluating the impact of behavioural insights in encouraging welfare-improving behaviours of a limited part of the global population, namely western industrialised countries. There is an increasing effort to make BPP more inclusive. There are also distributional effects as some behavioural public policies can harm certain population segments.
The bottom line
BPP is now established and embedded both as an academic field as well as a toolkit that policy makers use. It is likely to appear less in nudge units but more in general evaluation units, which will have a behavioural application. Bedding down and business as normal has advantages for BPP. Its cumulative program suits an incremental strategy of many tests and continuous tweaking while future innovations provide a way for BPP to keep on offering new benefits.
Want to read more?
- Behavioral public policy: past, present, & future – Sanchayan Banerjee and Peter John, Policy and Society, August 2025
Each fortnight The Bridge summarises a piece of academic research relevant to public sector managers.
- Published Date: 24 September 2025