In March 2024, Daniel Kahneman – the man who did perhaps more than anyone else to shape the field of behavioural public policy – died. He is among a small handful of scholars who have had a huge effect on my own career, and in this essay – the first in a series of essays in a special section of the Journal that honour him – I reflect on how his work inspired much of my own.

Governments around the world have increasingly adopted behavioural public policies, in which behavioural insights units (often designated as ‘Nudge units’) play an increasingly important role. Such units are typically assigned with implementing behavioural insights in various social policy fields. However, research on the contextual specificities of Nudge units is still scarce. This article addresses that gap by providing an in-depth qualitative study of MineduLAB, a Nudge unit active within the Peruvian Ministry of Education. Informed by an interpretive approach, our analysis shows that the behavioural insights that MineduLAB makes use of and develops, are enacted by a unique local interplay of three different dimensions: a political-financial, an epistemic community, and a sector-specific (here: educational) dimension. Moreover, our analysis of a Nudge unit in the Global South showcases both similarities (e.g. focus on behavioural evidence and experimentation) as well as differences (e.g. the challenge of corruption; the deployment of other vocabulary with regards to behavioural insights) with the predominantly Western Nudge units that are more commonly researched. Consequently, we argue that for a profound academic evaluation of behavioural public policy and the role of Nudge units herein, it is crucial to pay close attention to their contextuality and geographical diversity.

Behavioural public policy (BPP) operates within one of four cultural models of public management, an illustration of an influential scheme set out by Christopher Hood. Even though BPP can be fatalist, individualist or egalitarian, so far it has been hierarchicalist. Hallsworth's manifesto is largely an expression of this hierarchicalist form of public management, with all its limitations and contradictions. As the manifesto pays relatively little attention to decentralist and egalitarian approaches, it misses a radical opportunity. Future work on BPP could incorporate entrepreneurial and egalitarian possibilities while recognising the difficulties of moving away from hierarchalism completely. Even though Hood cautions against a ‘public management for all seasons’, it remains a plausible path for the next generation of researchers and practitioners of BPP.

Interventions are to the social sciences what inventions are to the physical sciences – an application of science as technology. Behavioural science has emerged as a powerful toolkit for developing public policy interventions for changing behaviour. However, the translation from principles to practice is often moderated by contextual factors – such as culture – that thwart attempts to generalize past successes. Here, we discuss cultural evolution as a framework for addressing this contextual gap. We describe the history of behavioural science and the role that cultural evolution plays as a natural next step. We review research that may be considered cultural evolutionary behavioural science in public policy, and the promise and challenges to designing cultural evolution informed interventions. Finally, we discuss the value of applied research as a crucial test of basic science: if theories, laboratory and field experiments do not work in the real world, they do not work at all.

Field experiments which test the application of behavioural insights to policy design have become popular to inform policy decisions. This study is the first to empirically examine who and what drives these experiments with public partners. Through a mixed-methods approach, based on a novel dataset of insights from academic researchers, behavioural insight team members and public servants, I derive three main results: First, public bodies have a considerable influence on study set-up and sample design. Second, high scientific standards are regularly not met in cooperative field experiments, mainly due to risk aversion in the public body. Third, transparency and quality control in collaborative research are low with respect to pre-analysis plans, the publication of results and medium or long-term effects. To remedy the current weaknesses, the study sketches out several promising ways forward, such as setting up a matchmaking platform for researchers and public bodies to facilitate cooperation, and using time-embargoed pre-analysis plans.

Surveys based on self-reported hygiene-relevant routine behaviors have played a crucial role in policy responses to the COVID-19 pandemic. In this article, using anchoring to test validity in a randomized controlled survey experiment during the COVID-19 pandemic, we demonstrate that asking people to self-report on the frequency of routine behaviors are prone to significant measurement error and systematic bias. Specifically, we find that participants across age, gender, and political allegiance report higher (lower) frequencies of COVID-19-relevant behaviors when provided with a higher (lower) anchor. The results confirm that such self-reports should not be regarded as behavioral data and should primarily be used to inform policy decisions if better alternatives are not available. To this end, we discuss the use of anchoring as a validity test relative to self-reported behaviors as well as viable alternatives to self-reports when seeking to behaviorally inform policy decisions.

Behavioural public policy (BPP) has come under fire by critics who claim that it is illiberal. Some authors recently suggest that there is a type of BPP – boosting – that is not as vulnerable to this normative critique. Our paper challenges this claim: there's no non-circular way to draw the distinction between nudge and boost that would make the normative difference required to infer the permissibility of a policy intervention from its type-membership. We consider two strategies: paradigmatic examples and causal mechanisms. We conclude by sketching some suggestions about the right way to approach the normative issues.