Kahneman and Tversky's ‘Prospect Theory’ paper famously demolishes expected utility theory as a predictive device. However, it presents deviations from that theory as ‘normatively unacceptable’ and argues that decision-makers would normally correct them when possible. In a later paper, Kahneman rejects a similar argument (the ‘discovered preference’ hypothesis) advanced by Plott. Later still, Kahneman endorses Sunstein and Thaler's ‘libertarian paternalism’, which aims to help people avoid deviating from their ‘true’ preferences. I report an email correspondence between Kahneman and me in which we debated whether his position on libertarian paternalism was consistent with his critique of Plott's hypothesis.

This paper examines Daniel Kahneman's concept of experienced utility and its roots in Bentham's hedonic utilitarianism. It focuses on Kahneman's call for a ‘separate value judgement’ to determine when experienced utility can be used to evaluate temporally extended outcomes (TEOs). Two potential judgements are proposed: comprehensiveness and personal independence. Comprehensiveness means that the measurement of utility captures all relevant aspects of instant utility. Personal independence means that the TEO is fully independent of other TEOs with which it might be combined (or ‘concatenated’). I argue that identifying TEOs meeting these criteria may be challenging, possibly restricting the applicability of experienced utility. I conclude by considering the implications for behavioural science's quest for an unambiguous, measurable operationalisation of utility.

This study empirically examines gender inequality in tolerance for women's opinions and identifies how the provision of normative gender-egalitarian message can mitigate this inequality by conducting online randomized experiments in Japan. In this experiment, I asked the participants to evaluate the agreement score for 10 anonymous statements and implemented two types of random interventions: disclosing the gender of the statement poster and providing normative statement for gender equality. The results of both cross-sectional and panel data analyses showed that people significantly reduced the agreement score for women's opinions compared with men's and non-gender disclosure opinions. Meanwhile, the negative impact of female gender disclosure was neutralized when participants were provided with a normative message.

Phishing emails cost companies millions. In the absence of technology to perfectly block phishing emails, the responsibility falls on employees to identify and appropriately respond to phishing attempts and on employers to train them to do so. We report results from an experiment with around 11,000 employees of a large U.S. corporation, testing the efficacy of just-in-time feedback delivered at a teachable moment – immediately after succumbing to a phishing email – to reduce susceptibility to phishing emails. Employees in the study were sent an initial pseudo-phishing email, and those who either ignored or fell victim to the phishing email were randomized to receive or not receive feedback about their response. Just-in-time feedback for employees who fell victim to or ignored the initial pseudo-phishing email reduced susceptibility to a second pseudo-phishing email sent by the research team. Additionally, for employees who ignored the initial email, feedback also increased reporting rates.

Many decisions are curated, incentivised or nudged by a third party. Despite this, only a handful of studies have looked at paternalistic decision-makers and the psychological processes by which they arrive at their decisions. The role of affect, in particular, has been ignored so far, and yet restricting agency on a potentially large group of people might be highly unpleasant. We are the first to propose a conceptual framework of affective paternalism which explicitly accounts for the role of affect in paternalistic decision-making, identifying all entry points through which affect may create systematic deviations in decision outcomes. We shed light on some of these phenomena by using a novel survey experiment in which we let participants make paternalistic decisions whilst also asking them about their motivations behind their choices, including cognitive reasons and affect. Our findings suggest that affect may play a significant role in paternalistic decision-making and lead to systematically different decision outcomes. To the extent that these that could result in inefficient, undesirable or unfair consequences, our framework may help more accurately predict a paternalist's decision and suggest entry points for where and possibly how to intervene in the paternalistic decision-making process.

Showering is one of the most water-intensive behaviours in urban households, accounting for 20–30% of water use. Real-time feedback from smart devices has been proven to significantly reduce water consumption in showers. Still, it is not known whether these devices have spillover effects on other water use behaviours. For the first time, we provide empirical evidence for a significant and negative within-domain spillover effect from the use of such devices, showing an increase in water use in other activities by 2.5% per day per household. Up to one-third of conservation effects are eroded by such spillovers, resulting in a two steps forward, one step back situation. Overall, however, net water use is still reduced by 4.7% in the 385 households that were observed. This study points out an important behavioural limit on the use of such smart shower devices and suggests that such use be accompanied by informational or other campaigns to reduce the large negative spillovers.

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.

Counter-serious and organised crime (SOC) strategies often include an awareness-raising element. Such messaging aims to build support for counter-SOC efforts, and intolerance for organised criminal activity. However, a growing body of research suggests that raising awareness to ‘social bads’ like SOC may risk backfiring by encouraging pessimistic attitudes about whether they can be controlled and could even nudge people to agree with populist narratives which argue that political outsiders represent the only hope for tackling systemic problems. A nationally representative survey experiment in Albania was conducted to test, for the first time, the impact of messages about SOC. Typical of counter-SOC messaging in practice, the first message emphasised the harms SOC causes. The second was more positive, highlighting high levels of social disapproval of SOC, a theme that social norms research suggests may be effective. We find that the first message backfires by reducing confidence in law enforcement and encouraging support for populist ideas. The second message is unexpectedly found to also encourage support for a populist sentiment, while having no positive impact on attitudes about law enforcement. This suggests that even positive messaging about ‘social bads’ can risk triggering unwanted responses.

I'm grateful to the authors for taking the time to read and respond to the manifesto. I have great respect for the contributions each of them has made to our field, and I'd like to offer some clarifications and reflections prompted by their thoughts.

A reduction in the demand for meat and particularly red meat has the potential to significantly enhance the sustainability and health of many people's diets. In the current work, I examine situational predictors of meat consumption in nationally representative nutrition surveys from three Western European countries: Switzerland, France and the Netherlands. More specifically, I examine whether the situational factors – the meal type, the day of the week and the location of the food consumption occasion – are predictive of whether meat and red meat are consumed. The results indicate that all three factors are linked to meat and red meat consumption with the patterns varying substantially across the different case study countries and in some cases also the gender of the consumer. The results emphasise the value of mapping situational correlates to inform situated interventions aimed at influencing meat consumption, while also highlighting important differences across both cultures and people.

Private refugee sponsorship is a desirable behaviour – it leads to positive outcomes for sponsors, refugees, the Canadian government and the general public. The most commonly reported motivations to sponsor are related to identity, including moral and national identity. Self-determination theory (SDT) suggests that identity is a strong intrinsic motivator; individuals who identify more strongly as a sponsor may be more intrinsically motivated to take on additional sponsorships. This proposed behavioural policy uses the components of SDT to design a certificate programme that bestows an official title on sponsors after completing a sponsorship. The certificate design reflects the three components of SDT (autonomy, competence and relatedness) and encourages moral and national incentives. Official titles are shown to increase identity with a role – titles act themselves as mechanisms of identity-building, which can lead to identity-motivated behaviours. The proposed certificate programme aligns with existing practices and resources already used by the Canadian government. It suggests that official titles could be a cost-effective mechanism for encouraging subsequent sponsorships.

Whether nudges succeed in promoting pro-environmental behavior strongly depends on their public acceptance. Prior literature shows that the framing of nudges, i.e., whether they address the individual (personal framing) or the society (societal framing), is one critical factor in determining nudging acceptance. Since a personal framing highlights the costs individuals have to bear to comply, we hypothesize that people accept nudges more when addressing the general public rather than themselves personally. We expect the framing effect to be stronger for nudges that elicit high-effort behavior than low-effort behavior. Results of multilevel linear regression analyses in two online experiments (nStudy 1 = 294, nobs = 4,410; nStudy 2 = 565, nobs = 11,300) reveal an opposite pattern: People accept nudges more when personally (vs societally) framed. As predicted, nudges receive higher support when the promoted behavior is perceived as low effort. Exploratory path analysis in Study 2 shows that the perceived effectiveness of the nudge mediates the positive relation between personal framing and nudging acceptance. This project provides novel insights on facilitators and barriers in nudging acceptance and their implications for policy-making.

Humankind's main defence against the virus that causes COVID-19 (SARS-CoV-2), besides vaccine development, was co-ordinated behaviour change. In many countries, co-ordination was assisted by tracking surveys designed to measure self-reported behaviour and attitudes. This paper describes an alternative, complementary approach, which was undertaken in close collaboration with officials in the Department of the Taoiseach (Irish Prime Minister). We adapted the Day Reconstruction Method (DRM) to develop the ‘Social Activity Measure’ (SAM). The study was conducted fortnightly for 18 months, with findings delivered directly to the Department. This paper describes the method and shows how SAM generated a detailed picture of where and why transmission risk occurred. By using the DRM, we built aggregate measures from narrative accounts of how individuals spent their previous day. SAM recorded the amount, location and type of social activity, including the incidence of close contact and mask-wearing, as well as compliance with public health restrictions by shops and businesses. The method also permitted a detailed analysis of how public perceptions and comprehension are related to behaviour. The results informed government communications and strategies for lifting public health restrictions. The method could be applied to other future situations that might require co-ordinated public behaviour over an extended period.

Promoting agency – people's ability to form intentions and to act on them freely – must become a primary objective for Behavioural Public Policy (BPP). Contemporary BPPs do not directly pursue this objective, which is problematic for many reasons. From an ethical perspective, goals like personal autonomy and individual freedom cannot be realised without nurturing citizens’ agency. From an efficacy standpoint, BPPs that override agency – for example, by activating automatic psychological processes – leave citizens ‘in the dark’, incapable of internalising and owning the process of behaviour change. This may contribute to non-persistent treatment effects, compensatory negative spillovers or psychological reactance and backfiring effects. In this paper, we argue agency-enhancing BPPs can alleviate these ethical and efficacy limitations to longer-lasting and meaningful behaviour change. We set out philosophical arguments to help us understand and conceptualise agency. Then, we review three alternative agency-enhancing behavioural frameworks: (1) boosts to enhance people's competences to make better decisions; (2) debiasing to encourage people to reduce the tendency for automatic, impulsive responses; and (3) nudge+ to enable citizens to think alongside nudges and evaluate them transparently. Using a multi-dimensional framework, we highlight differences in their workings, which offer comparative insights and complementarities in their use. We discuss limitations of agency-enhancing BPPs and map out future research directions.

Effective communication is essential for delivering public health messages and enabling behaviour change. Little is known about possible backfiring, or spillover effects, of COVID-19 vaccine messaging. In a study with n = 1,848 United Kingdom (UK) adults, we assess whether communication strategies that target vaccine hesitancy have any unintended, positive or negative, spillover effects on people's intention to engage in protective, compliance and prosocial behaviours. In June–July 2021, we conducted an online experiment to assess the potential spillover effects of three messages, emphasising (a) the medical benefits of COVID-19 vaccination, (b) the non-medical collective benefits of vaccination or (c) the non-medical individual benefits of holding a vaccination certificate. Exposure to different messages did not significantly affect people's intention to engage in protective, compliance, or prosocial behaviours. Instead, vaccination status (being vaccinated vs not) was positively associated with intentions to engage in protective, compliance and prosocial behaviours. Our results suggest that communication strategies that aim to increase vaccination uptake do not have any unintended effects on other health behaviours and vaccination campaigns can be tailored to specific populations to increase uptake and compliance.

Recently, there has been a lively discussion of “Hayekian Behavioral Economics” in Behavioral Public Policy). We aim to contribute to this debate by identifying the main building blocks of a Hayekian psychology. We highlight that the starting point for Hayek was the quest to understand why humans are typically quite successful in navigating the world. In Hayek's framework, the individual mind is conceptualized as a “system within a system”, i.e., the mind is a complex adaptive system that is continuously interacting with the wider socio-cultural system. Three core ideas are central to a Hayekian psychology: subjectivity, learning and adaptation. We argue that these ideas are quite different from the still dominant heuristics-and-biases perspective and lead to different emphases in economic and social science explanations. One, economists should be cautious in their interpretation of experimental findings since subjective meaning is central to agents' behavior. Two, static and isolated models of individuals' biases might underestimate people's capacity to learn with and from others. And three, despite complex processes of adaptation of the mind and the market, a Hayekian framework is consistent with economists' “explanations of the principle” and “pattern predictions.”

People buy some goods that they do not enjoy and wish did not exist. They might even be willing to pay a great deal for such goods, whether the currency involves time, commitment or money. One reason involves signaling to others; so long as the good exists, nonconsumption might give an unwanted signal to friends or colleagues. Another reason involves self-signaling; so long as the good exists, nonconsumption might give an unwanted signal to an agent about himself or herself. Yet another reason involves a combination of network effects and status competition; nonconsumption might deprive people of the benefits of participating in a network and thus cause them to lose relative position. With respect to real-world goods (including activities) of this kind, there is typically heterogeneity in relevant populations, with some people deriving positive utility from goods to which other people are indifferent, or which other people deplore. Efforts to measure people's willingness to pay for goods of this kind will suggest a welfare gain, and possibly a substantial one, even though the existence of such goods produces a welfare loss, and possibly a substantial one. Collective action, private or public, is necessary to eliminate goods that people consume but wish did not exist. Legal responses here might be contemplated when someone successfully maneuvers people into a situation in which they are incentivized to act against their interests, by consuming a product or engaging in an activity they do not enjoy, in order to avoid offering an unwanted signal. Prohibitions on waiving certain rights might be justified in this way; some restrictions on uses of social media, especially by young people, might be similarly justified.

Some products, notably but not only platforms, increase in value for users as the number of other users increases. These interaction or network effects can result in ‘product market traps’ (Bursztyn et al., 2023) where people who use the product would be better off if they all stopped using it and switched to another product, but cannot because of coordination problems. A parallel but overlooked phenomenon is the labor market trap, where employees would be better off if they collectively left an employer, job, or profession, but cannot because of the difficulty of coordination. Product market and labor market traps pose a challenge to public policy because of the complexity of people's behavior in networks, but can be mitigated in some cases with relatively simple taxes and regulatory interventions.