This study investigated determinants of the willingness to get vaccinated in India and examined the relationship between engagement in preventive behaviours and vaccine uptake intent. A large-scale online survey covering aspects of COVID-19 preventive behaviours, vaccination status, moral emotions, trust in others, role models, and socio-demographics was used. A total of 953 Indians participated in the survey between May and June 2021, of which 770 contained valid data on vaccination status. Past preventive health behaviours (PHBs) such as avoiding social gatherings, higher interpersonal trust, and moral emotions were robustly associated with the willingness to take a COVID-19 vaccine. Results also showed that unvaccinated individuals were less likely to follow other PHBs, like wearing a mask; past COVID-19 infection status was associated with similar lower adherence to PHBs. Given the strong associations between positive moral emotions, like gratitude, and vaccine uptake intent (especially in the unvaccinated subsample), targeted communication interventions can boost uptake intent, and subsequently vaccine uptake, in jurisdictions with low vaccination rates.

The over-utilization of plastic bags has pushed governments to implement a mix of policy measures ranging from banning the bags altogether to charging a fee for them. However, these policies are often accompanied by unintended consequences. Paying for plastic bags, in particular, may crowd out the negative emotions tied to their harmful impact on the environment, and may be subject to a ‘rebound effect’. In a randomized controlled experiment, I tested four different treatments aimed at nudging or encouraging consumers to carry their own bag to the stores. Specifically, I tested the effects of changing the framing of the question regarding carrier bags at the checkout till in stores using a yes/no response format, in which the yes option corresponds to the desired behaviour. The treatment with the yes/no framing format was found to have as strong and significant an effect as a charge of 5 pence per bag on discouraging single-use plastic bag consumption.

Nancy Cartwright argues that evidence-based policies should not only rely on randomized controlled trials (RCTs) to test their effectiveness – they should also use horizontal and vertical searches to find support factors and causal principles that help define how those policies work. This paper aims at analyzing Cartwright's epistemology regarding evidence-based policies and their use of RCTs while applying her findings to current research involving nudges as behavioral public policy interventions. Holding a narrowly instrumental view of rationality, nudge theory tends to neglect other expressive components. Policymakers, in their quest for causal principles, should consider the expressive rationality of individuals in their research. This inclusion would not only increase the effectiveness of nudges, but also address some ethical issues related to people's autonomy when targeted by these interventions.

This paper offers an interpretation of the behavioural evidence that casts doubt over whether people always have preferences or, if they do, that they are stable. If people do not have preferences in this sense, then the usual policy evaluation standard of preference satisfaction cannot be used in these cases. The paper then develops, to fill this gap, a Millian policy framework where policy is judged by whether it advances what Mill understands by individual liberty in On Liberty. This yields many recognisable policies but offers a different evaluative standard for them. It also yields some policy innovations: e.g. a basic income and a flat tax.

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.

Some cancer screening programs are built on contentious evidence, but the public are generally positive about screening. Many professional organizations have settled on a fudge: allow the people to decide for themselves. Given the potential limitations of individual decision-making, there is increasing support for helping individuals to make better decisions. This paper presents experimental data supporting the claim that individuals are largely unresponsive to data about screening and base their decisions upon factors that professionals would consider inappropriate reasons for screening. The most plausible explanation for this phenomenon comes from accessibility bias. Professionals can no longer sustain the argument that, with respect to cancer screening, individual choice reflects a meaningful expression of autonomy.

We provide experimental evidence for the existence of “rent stigma,” a preference for owning goods or real estate to renting them. In one experiment, anonymous respondents preferred owning a car or house to renting them, even though the transaction was constructed to be identical in each case in terms of economic payoffs and risk. In a second experiment, a survey of law students who were asked how much they would pay to own rather than rent a laptop found similar results. However, we found little or no evidence for our hypotheses that rent stigma would decline in conditions in which the advantages of renting were made salient. The existence of rent stigma raises concerns that the framing of a transaction in terms of purchasing rather than rent may be used to manipulate consumers.

In Indonesia, as in other countries, a large proportion of tax returns are filed at the last minute. In a population-wide randomised controlled trial (n = 11,157,069), we evaluated the impact of behavioural email prompts on the proportion of annual tax returns filed at least two weeks before the deadline; and overall filing rate. In two control conditions, taxpayers either received no email or an email used in prior years, emphasising regulatory information. The five treatments informed by behavioural science were (1) a simplified version of the existing email, emphasising early filing; (2) the simplified version with additional guidance on filing taxes; (3) the simplified version with a planning prompt and option to sign up for email reminders; (4) a version combining treatments 1, 2 and 3; and (5) an email appealing to national pride. Compared to the no-email control, all emails led to a statistically significant increase in early and overall filing rates. The planning email (3) was the most effective, increasing early filling from 34.9% to 37% (b 2.07 percentage points (pp), p < 0.001, 95% confidence interval (CI) 1.97–2.17pp), and overall filing from 65.6% to 66.7% (b 1.10pp, p < 0.001, 95% CI 0.99–1.19pp).

Do small wording differences in message-based behavioral interventions have outsized effects on behavior? An influential initial study, examining this question in the domain of political behavior using two small-scale field experiments, argues that subtle linguistic cues in voter mobilization messages describing someone as a voter (noun) instead of one who votes (verb) dramatically increases turnout rates by activating a person's social identity as a voter. Two subsequent large-scale replication field experiments challenged this claim, finding no effect even in electorally competitive settings. However, these experiments may not have reproduced the psychological context needed to motivate behavioral change because they did not occur in highly competitive and highly salient electoral contexts. Addressing this major criticism, we conduct a large-scale, preregistered replication field experiment in the 2016 presidential election. We find no evidence that noun wording increases turnout compared to verb wording in this highly salient electoral context, even in competitive states.

In the past decades, behavioral economics has credibly identified numerous decision-making biases leading people to make choices they would not have made if better informed about the long-term consequences of their actions. This has given rise to a new reason for government interventions: internalities. In contrast to traditional reasons for government intervention, such as redistribution and externalities, overcoming internalities often involves the use of paternalistic policies. We investigate theoretically and empirically the formation of attitudes toward paternalistic policies. Theoretically, we focus on the role of self-interest and distinguish between self-interest as construed for the rational decision-maker, self-interest when self-control problems are present, and self-interest when procedural or expressive elements, such as autonomy, matter. Empirically, we employ two novel data sets: a Danish survey on political opinion combined with administrative data on actual behavior and a large-scale cross-country survey to analyze attitudes toward paternalistic policies in the health and financial domains. We show that targets of paternalism are more opposed to paternalism than non-targets both in Denmark and across nine Western democracies and rely on our theoretical priors to explore mechanisms that can explain these attitudes.

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.

Behavioural economists often claim that their policy recommendations are justified by cost–benefit analysis (CBA), but without adequate explanation of the methodology they have in mind. I sketch the outlines of a CBA methodology that is compatible with the findings of behavioural economics and is in accord with my account in Sugden (2018) of a well-functioning market as a network of opportunities for mutually beneficial transactions. The key idea is that the CBA of a project is concerned only with effects that are not transmitted through voluntary interactions. I illustrate this proposal by considering the appraisal of fuel economy mandates.

Behavioural science has made significant contributions to public policy over the last decade from tax compliance to pensions and energy use. However, behavioural insights (BI) have not yet been able to claim significant policy shifts in the area of crime, despite increasing interest and experimentation. This paper offers a critical reflection on the state of BI and crime from the perspective of those who have been at the forefront of this work since the inception of the world's first behavioural science team in government. We outline how existing theories of crime have already laid foundations for the successful application of BI but identify opportunities to build on these with tools from behavioural science. We conclude by examining how continued cross-pollination of ideas between BI and disciplines such as applied criminology points to promising directions for future research.

Parochialism, by which we mean in-group preferences and out-group prejudice, has the potential to influence public policy. In-group preferences and out-group prejudice can lead individuals to evaluate a policy based on how that policy affects the groups they belong to rather than on the basis of their ideological priors or the impact of that policy on society at large. Unchecked, parochialism likely leads to problematic policies and perverse social outcomes. While the evidence suggests that this bias can be mitigated if issues are framed in ways that encourage reflection as opposed to unreflective immediate responses, policy makers face incentives to leverage parochialism rather than combat it. The solution may instead require limiting policy makers and our ability to make decisions for others and promoting an institutional environment that encourages our interacting with diverse others rather than insularity. Stated another way, limited government and open society may be the path beyond our parochialism.

We evaluate whether people will outsource their opinion on public policy to consensus conference participants. The ideal consensus conference brings together a representative sample of citizens and introduces them to the range of perspectives and evidence related to some policy. The sample is given the opportunity to ask questions of experts and to deliberate. Attitudes about each policy are queried before and after the conference to see if the event has changed minds. In general, such conferences do produce opinion shifts. Our hypothesis is that the shift can be leveraged by simply communicating conference results – absent substantive information about the merits of the policies discussed – to scale up the value of conferences to the population at large. In five studies, we tell participants about the impact of a consensus conference on a sample of citizens’ opinions for a range of policies without providing any new information about the inherent value of the policy itself. For several of the policies, we see a shift in opinion. We conclude that the value of consensus conferences can be scaled up simply by telling an electorate about its results. This suggests an economical way to bring evidence and rational argument to bear on citizens’ policy attitudes.

I comment on Sunstein's paper proposing ‘Hayekian behavioural economics’. In essence, Sunstein is merely renaming a familiar approach to normative economics, initiated in Sunstein and Thaler's seminal 2003 paper. I argue that this approach cannot fairly be described as in the spirit of Hayek's work. Sunstein's approach is based on a ‘constructivist’ conception of rationality that Hayek consistently criticized. Although both Hayek and Sunstein address ‘knowledge problems’, the two problems are fundamentally different. I develop what I claim are truly Hayekian critiques of Sunstein's claim that fuel economy mandates can be more Hayekian than carbon taxes.

A substantial experimental literature in behavioral economics and psychology finds that individuals rely on heuristics and cognitive biases when they make decisions. These heuristics and biases impact the choices of individuals from all walks of life, including police officers entrusted with the power to enforce laws. Individuals act within an institutional context. We examine how the institutions that structure American policing interact with the heuristics and biases of individual police officers. We then suggest institutional changes that may result in better performance from boundedly rational police officers.

The aim of this study is to respond to Cass Sunstein's question: ‘Why are some nudges ineffective, or at least less effective than choice architects hope and expect?’—particularly in view not only of the rational basis in decision-making but also of the direct influence of emotions on the behavior of those who must choose. In this study, I used findings from psychology surveys, specifically considering the influence of emotions on the fallibility of nudges in social interactions when wealth is compared. Special attention is dedicated to vanity, a combined emotion that leads to emotional choices, which arises in self-presentation and self-comparison when external signs of wealth are displayed. Imagination plays an important role in simulation to the extent that it causes failure in further nudges. In conclusion, I argue that vanity impels people to act differently, as expected of choice architects.

A concern that people ought to be given what they deserve, in both positive and negative senses, lies deep within the human psyche. Views on the level of reward or punishment that a person deserves for their actions will differ across persons, places, and time, but, I argue in this article, depend substantively upon some combination of intentions and outcomes. Using these characteristics, I propose a taxonomy of actions, ordered from most to least blameworthy, with, for example, it being suggested that for any particular level of harm an intentional yet unrealized harm is more blameworthy than an unintentional yet realized harm (a similar taxonomy can be developed for the positive domain of praiseworthy actions). The taxonomy is focused upon people's actions toward others, but I finish the article with a discussion of desert in relation to people's intentions toward themselves. Ultimately, I contend that the strength and sustainability of public sector services and welfare systems, not to mention our private relationships, rely upon the recognition that desert underpins our notion of justice.