Nudging has become a well-known policy practice. Recently, ‘boosting’ has been suggested as an alternative to nudging. In contrast to nudges, boosts aim to empower individuals to exert their own agency to make decisions. This article is one of the first to compare a nudging and a boosting intervention, and it does so in a critical field setting: hand hygiene compliance of hospital nurses. During a 4-week quasi-experiment, we tested the effect of a reframing nudge and a risk literacy boost on hand hygiene compliance in three hospital wards. The results show that nudging and boosting were both effective interventions to improve hand hygiene compliance. A tentative finding is that, while the nudge had a stronger immediate effect, the boost effect remained stable for a week, even after the removal of the intervention. We conclude that, besides nudging, researchers and policymakers may consider boosting when they seek to implement or test behavioral interventions in domains such as healthcare.

Behavioral public policies are aimed at influencing the behavior of the public in a way that is advantageous for the public itself and within the law. Sanders, Snijders and Hallsworth (2018, this issue) summarize the state of the art of this new field of study and introduce a number of challenges and opportunities for the time to come. We address an additional challenge that is present and central in all attempts to influence behavior, namely the public – the people that are the target of behavioral public policies. We review evidence revealing that people do not passively accept those influence attempts, but often show reactant responses. We propose that the Persuasion Knowledge Model provides a framework both to understand the reactions of the public and to facilitate communication between academic researchers and practitioners.

We examine the causes and policy implications of strategic (willful) ignorance of risk as an excuse to over-engage in risky health behavior. In an experiment on Copenhagen adults, we allow subjects to choose whether to learn the calorie content of a meal before consuming it and then measure their subsequent calorie intake. Consistent with previous studies, we find strong evidence of strategic ignorance: 46% of subjects choose to ignore calorie information, and these subjects subsequently consume more calories on average than they would have had they been informed. While previous studies have focused on self-control as the motivating factor for strategic ignorance of calorie information, we find that ignorance in our study is instead motivated by optimal expectations – subjects choose ignorance so that they can downplay the probability of their preferred meal being high-calorie. We discuss how the motivation matters to policy. Further, we find that the prevalence of strategic ignorance largely negates the effects of calorie information provision: on average, subjects who have the option to ignore calorie information consume the same number of calories as subjects who are provided no information.

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.

We argue that the diverse components of a choice architecture can be classified into two main dimensions – Message and Environment – and that the distinction between them is useful in order to better understand how nudges work. In the first part of this paper, we define what we mean by nudge, explain what Message and Environment are, argue that the distinction between them is conceptually robust and show that it is also orthogonal to other distinctions advanced in the nudge literature. In the second part, we review some common types of nudges and show they target either Message or Environment or both dimensions of the choice architecture. We then apply the Message–Environment framework to discuss some features of Amazon's website and, finally, we indicate how the proposed framework could help a choice architect to design a new choice architecture.

This article comments on the role of empirical subjective wellbeing research in public policy within a constitutional, procedural perspective of government and state. It rejects the idea that, based on the promises of the measurement, we should adopt a new policy perspective that is oriented toward a decision rule maximizing some aggregate measure of subjective wellbeing. This social engineering perspective, implicit in much reasoning about wellbeing policy, neglects: (1) important motivation problems on the part of government actors, such as incentives to manipulate indicators, but also on the part of citizens to truthfully report their wellbeing; and (2) procedural utility as a source of wellbeing. Instead, wellbeing research should be oriented toward gaining insights that improve the diagnoses of societal problems and help us to evaluate alternative institutional arrangements in order to address them, both as inputs into the democratic process.

Five experiments are reported to compare models of attitude formation about hot-button policy issues like climate change. In broad strokes, the deficit model states that incorrect opinions are a result of a lack of information, while the cultural cognition model states that opinions are formed to maximize congruence with the group that one affiliates with. The community of knowledge hypothesis takes an integrative position. It states that opinions are based on perceived knowledge, but that perceptions are partly determined by the knowledge that sits in the heads of others in the community. We use the fact that people's sense of understanding is affected by knowledge of others’ understanding to arbitrate among these views in the domain of public policy. In all experiments (N = 1767), we find that the contagious sense of understanding is nonpartisan and robust to experimental manipulations intended to eliminate it. While ideology clearly affects people's attitudes, sense of understanding does as well, but level of actual knowledge does not. And the extent to which people overestimate their own knowledge partly determines the extremity of their position. The pattern of results is most consistent with the community of knowledge hypothesis. Implications for climate policy are considered.

One of Friedrich Hayek's most important arguments pointed to the epistemic advantages of the price system, regarded as an institution. As Hayek showed, the price system incorporates the information held by numerous, dispersed people. Like John Stuart Mill, Hayek also offered an epistemic argument on behalf of freedom of choice. A contemporary challenge to that epistemic argument comes from behavioral economics, which has uncovered an assortment of reasons why choosers err, and also pointed to possible distortions in the price system. But, even if those findings are accepted, what should public institutions do? How should they proceed? A neo-Hayekian approach would seek to reduce the knowledge problem by asking what individual choosers actually do under epistemically favorable conditions. In practice, that question can be disciplined by asking five subsidiary questions: (1) What do consistent choosers, unaffected by self-evidently irrelevant factors, end up choosing? (2) What do informed choosers choose? (3) What do active choosers choose? (4) When people are free of behavioral biases, including (say) present bias or unrealistic optimism, what do they choose? (5) What do people choose when their viewscreen is broad, and they do not suffer from limited attention? These questions are illustrated with reference to the intense controversy over fuel economy standards.

Robert Sugden has advanced various critiques of behavioural welfare economics, offering the notion of opportunity as an alternative. We agree with much of Sugden's critique but argue that his approach would benefit from a broadening of the informational base beyond opportunities to include people's concern for decision processes. We follow Amartya Sen in arguing that the process through which choices are made (process freedom) is something individuals care about beyond the availability of choice options (opportunity freedom) as they value a sense of agency. We argue that individuals’ agentic capabilities are crucial for people's process freedom and hence for their sense of agency. In the final section of the paper, we sketch the institutional implications of our argument, i.e. what a joint consideration of opportunities and agentic capabilities means for behavioural public policy.

Recent work by Kahan et al. (2017) on the psychology of motivated numeracy in the context of intracultural disagreement suggests that people are less likely to employ their capabilities when the evidence runs contrary to their political ideology. This research has so far been carried out primarily in the USA regarding the liberal–conservative divide over gun control regulation. In this paper, we present the results of a modified replication that included an active reasoning intervention with Western European participants regarding both the hierarchy–egalitarianism and individualism–collectivism divides over immigration policy (n = 746; considerably less than the preregistration sample size). We reproduce the motivated numeracy effect, though we do not find evidence of increased polarization of high-numeracy participants.

Evidence on the effectiveness of health promotion interventions is mixed, especially in terms of the magnitude of their impact and long-term adherence. This paper proposes a comprehensive approach informed by behavioural economics of developing behavioural change programmes, which is designed to educate, activate, engage and empower people by taking into consideration individual and social mechanisms. Three applied pilots and their results are presented in order to illustrate the approach using cognitive and social mechanisms to lead to better health outcomes, individually and community-wide. More research is needed to explore levers and barriers for the systemic adoption of this framework in implementing health promotion interventions.

Al-Ubaydli et al. provide a far-reaching, insightful and directly actionable analysis of how social-behavioral research may exert more influence over the development and implementation of public policy. Their paper offers a sophisticated understanding of the ‘scale-up effect’, or factors that influence the extent to which positive experimental effects replicate as an intervention is implemented more broadly. Using economic principles, models and analyses, they offer 12 proposals for improving the process of scaling up effective and policy-relevant interventions. The current paper outlines how their proposals share a number of complementary features with behavioral psychology and applied behavior analysis. This response considers three possible points of intersection: (1) perspectives on the importance and challenges of studying and controlling our own behavior; (2) approaches to determining the social value of intervention outcomes and the procedures for achieving them; and (3) recommendations for deploying meaningful, common measures across phases of research.

Toilet ownership in India has grown in recent years, but open defecation can persist even when rural households own latrines. There are at least two pathways through which social norms inhibit the use of toilets in rural India: (1) beliefs/expectations that others do not use toilets or latrines or find open defecation unacceptable; and (2) beliefs about ritual notions of purity that dissociate latrines from cleanliness. A survey in Uttar Pradesh, India, finds a positive correlation between latrine use and social norms at baseline. To confront these, an information campaign was piloted to test the effectiveness of rebranding latrine use and promoting positive social norms. The intervention targeted mental models by rebranding latrine use and associating it with cleanliness, and it made information about growing latrine use among latrine owners more salient. Following the intervention, open defecation practices went down across all treatment households, with the average latrine use score in treatment villages increasing by up to 11% relative to baseline. Large improvements were also observed in pro-latrine beliefs. This suggests that low-cost information campaigns can effectively improve pro-latrine beliefs and practices, as well as shift perceptions of why many people still find open defecation acceptable. Measuring social norms as described can help diagnose barriers to reducing open defecation, contribute to the quality of large-scale surveys and make development interventions more sustainable.

Al-Ubaydli et al. point out that many research findings experience a reduction in magnitude of treatment effects when scaled, and they make a number of proposals to improve the scalability of pilot project findings. While we agree that scalability is important for policy relevance, we argue that non-scalability does not always render a research finding useless in practice. Three practices ensuring (1) that the intervention is appropriate for the context; (2) that heterogeneity in treatment effects are understood; and (3) that the temptation to try multiple interventions simultaneously is avoided can allow us to customize successful policy prescriptions to specific real-world settings.

Nudges based on social norms (norm-nudges) can be compelling behavioral interventions compared with traditional interventions such as taxes and regulations, but they do not work in all circumstances. We tested two empirical norm-nudge frames in an online experiment on taking measures for flood preparedness with large samples of homeowners (N = 1805) in two European countries, to evaluate the possible interactions between norm-nudge effectiveness, individual characteristics, and intercultural differences. We contrasted these norm-nudge treatments with a control and norm-focusing treatment by asking respondents to express their beliefs about what other respondents would do before making a decision relevant to their own payoff. We find no evidence of a treatment effect, suggesting that our social norm-nudges do not affect flood preparedness in the context of a flood risk investment game.

Citizen activists play a role in translating public concern about the climate crisis to policymakers and elevating it on the political agenda. We consider the dynamic between citizen activists and the decision-makers they seek to influence and we review psychological research relevant to advocating for climate legislation. We conducted a study with citizen activists who lobby the US Congress for a carbon pricing policy to address climate change. The study assessed how activists think about four social psychological approaches: affirmation, social norms, legacy and immediacy. The findings provide a window into activists’ intuitions about which strategies to use, whom to use them with and their perceived effectiveness. A strategy of establishing shared values and common ground (affirmation) was used most frequently overall. A strategy emphasizing the long-term costs and benefits of addressing climate change (legacy) was employed less frequently than affirmation and seen as less effective by activists but it was the only strategy that was associated with perceived increases in Congressional Representatives’ support of the policy. Citizen activists and their interactions with elected officials provide an opportunity for social-behavioral scientists to understand and potentially overcome barriers to enacting climate policy.

Professor Sunstein (2017) discusses the possible causes for and policy implications of the failure of nudges, with special attention to defaults. Though he focuses on nudges that fail when they should succeed, Sunstein recognizes that some failures reveal that a nudge should not have been attempted to begin with. ‘Nudges that fail’, however, does not consider fully the relationship between the outcomes of nudging and their likely welfare effects, most notably neglecting the troubling case of nudges that succeed when they should fail. Hence, after clarifying the boundaries of legitimate nudging within a libertarian-paternalistic approach and noting the fourfold relationship between the efficacy of nudging and its normative desirability, this article evaluates more fully the case of failed nudges and examines the hitherto unaddressed problem of successful yet undesirable nudges. This analysis shows that the failure of nudging bears only limited diagnostic value, while the success of a nudge is even less indicative of its normative status. The article concludes with recommendations for policy-makers who wish to employ nudges that are not only efficacious, but also likely to advance the subjective well-being of the individuals they target.

Poor compliance of prescription medication is an ongoing public health crisis. Nearly half of patients do not take their medication as prescribed, harming their own health while also increasing public health care costs. Despite these detrimental consequences, prior research has struggled to establish cost-effective and scalable interventions to improve adherence rates. We suggest that one reason for the limited success of prior interventions is that they make the personal health costs of non-adherence insufficiently prominent, while a higher saliency of these costs may motivate patients to adhere more. In the current research, we test whether an intervention that makes the personal health costs of non-compliance more salient for patients will increase their medication adherence. To do so, we conducted a randomized controlled trial with 16,191 patients across 278 UK pharmacies over a 9-month time period and manipulated the perceived consequences of medication non-adherence. We find that patients who received a treatment highlighting the personal health costs of non-compliance were significantly more likely to adhere to their medication than three comparison groups (odds ratio = 1.84, 95% confidence interval = 1.37–2.47). Shifting patients’ focus to the personal health costs of non-compliance may thus offer a potentially cost-effective and scalable approach to improving medication adherence.

Although the need for urgent climate change action is clear, insights about how to make better climate risk management decisions are limited. While significant attention from behavioral researchers has focused on choice architecture, we argue that many of the contexts for addressing climate risks require increased attention to the needs of a deliberative and dynamic choice environment. A key facet of this kind of decision is the need for decision-makers and stakeholders to identify and balance conflicting economic, social and environmental objectives. This recognition of difficult, context-specific trade-offs highlights the need for structuring the decision-making process so that objectives are clearly articulated and prioritized. Equally, policy analyses and deliberations must effectively link priorities with climate risk management options. This restructuring of decision-making about climate change calls for more than a nudge. Scientific and technical efforts must be redirected to help stakeholders and decision-makers better understand the diverse implications of climate change management alternatives and to become better equipped to take actions commensurate with the urgency of the problem.

We present a series of studies documenting what we call a ‘thick skin bias’ in people's perceptions of those living in poverty. Across a wide range of life events, from major to minor, people of lower socioeconomic status (SES) are systematically perceived as being less harmed by negative experiences than higher-SES people, even when this is patently false. In 18 studies, including a pre-registered survey of a nationally representative sample, we find that laypeople and professionals show the thick skin bias. We distinguish the bias from a tendency to dehumanize those in poverty and argue it cannot be attributed to the belief that the mere expectation that bad things will happen buffers people in poverty from suffering. The thick skin bias has potentially profound implications for the institutional and interpersonal neglect of those most in need of greater care and resources.