This article explores the ‘rationality wars’, contemporary debates about the nature and scope of rationality across economics, psychology, behavioral public policy and philosophy. It traces the evolution of the concept from classical thinkers and shows how modern disagreements – such as Daniel Kahneman’s logical model versus Gerd Gigerenzer’s ecological approach – restate long-standing philosophical tensions. These divergences arise from the distinct epistemological demands of each discipline. Using Gustavo Bueno’s distinction between concepts (discipline-specific) and ideas (transdisciplinary), the article critiques reductionist attempts to impose one framework as definitive. Instead, it argues for a pluralistic, scientifically grounded understanding of rationality that respects diverse aims, methods and standards.

This paper explores the complexities and unintended consequences of conflict of interest (COI) disclosures in various professional settings. It highlights key psychological processes encountered by recipients of such disclosures. Notably, it describes the burden of disclosure effect, which paradoxically reduces trust while increasing compliance due to social pressures, and disclosure's expertise cue, where disclosures inadvertently increase trust and persuasiveness by signalling expertise. The paper also outlines best practices for improving COI disclosures, emphasising the need for external third-party involvement and encouraging deliberation. It concludes that effective disclosure depends not only on how recipients process information but also critically on how the disclosure influences the behaviour of advisors, underscoring the need for a holistic approach to managing COIs that goes beyond mere transparency. A version of this paper was presented as a keynote at the Second Annual International Behavioural Public Policy Conference at the University of North Carolina in September 2023.

Since the emergence of psychological and behavioural science, one of its foundational goals has been to explain human behaviour. Although the discipline has been highly successful in this endeavour, there is an elephant in the room. Psychological and behavioural science has neglected studying the most challenging aspect of human behaviour−transformative behavioural change. This change can be described as a fundamental and difficult-to-achieve shift in someone’s actions that involves a transformation of one’s way of living. Understanding transformative behavioural change is essential not only for psychological and behavioural science to accomplish its foundational goal but also to maintain its contemporary relevance. Indeed, it is imminent that both solving the world’s biggest issues (e.g., climate change) and living through major disruptions (e.g., technological revolution) will require people to transform their behaviour. In this perspective, I first review and discuss previous relevant research, and then propose a seven-step agenda for how psychological and behavioural science can become the science of transformative behavioural change.

The research of many decades by behavioral economists and psychologists has shown that the standard rationality axioms do not describe how individuals actually behave in many circumstances. Nevertheless, behavioral economists still argue for the normative character of the axioms: they describe how individuals should behave. Violations of the axioms are red flags for some type of pathology. This article argues that the history of the axiomatic approach in economics does not lend support to the normative case. Furthermore, it is argued analytically that the rationality axioms are vacuous. The attribution of irrationality to behavior can only be accomplished by reference of a more inclusive idea of rationality. The axioms are too thin and misleading. They do not have policy significance.

The effectiveness and uptake of financial incentives can differ substantially between reward- and deposit-based incentives. Therefore, it is unclear to whom and how different incentives should be assigned. In this study, the effect of different modes of assigning reward- and deposit-based financial incentives on effort is explored in a two-session experiment. First, students’ (n = 228, recruited online) discounting, loss aversion and willingness to pay a deposit were elicited. Second, an incentivized real-effort task was completed (n = 171, 25% drop-out). Two modes of assigning reward- or deposit-based financial incentives were compared: random assignment and ‘nudged’ assignment – assignment based on respondent characteristics allowing opting out. Our results show that respondents receiving nudged assignment earned more and persisted longer on the real-effort task than respondents randomly assigned to incentives. We find no differences in effectiveness between reward-based or deposit-based incentives. Overall, 39% of respondents in the nudged assignment mode followed-up the advice to take deposit-based incentives. The effect of deposit-based incentives was larger for the respondents who followed-up the advice than for respondents that randomly received deposit-based incentives. Overall, these findings suggest that nudged assignment may increase incentives’ effect on effort. Future work should extend this approach to other contexts (e.g., behaviour change).

It is perhaps uncontroversial to claim that behavioral science research is playing an increasingly important role in practice. However, practitioners largely rely on media reports rather than original research articles to learn about the science. Do these media reports contain all the information needed to understand the nuances of the research? To assess this question, we develop a set of rubrics to evaluate the fidelity of the media report to the original research article. As an illustration, we apply these rubrics to a sample of media reports based on several research articles published in one journal and identify common patterns, trends, and pitfalls in media presentations. We find preliminary evidence of low fidelity in presenting participant characteristics, contextual elements, and limitations of the original research. The media also appear to misreport correlational evidence as causal and sometimes miss acknowledging the hypothetical nature of evidence when hypothetical scenarios were used as the sole basis of conclusions. Furthermore, the media often present broad conclusions and personal opinions as directly backed by scientific evidence. To support more discerning consumption of behavioral insights from media sources, we propose a checklist to guide practitioners in evaluating and using information from media sources.

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.

Despite a long history of research on democratic backsliding, the process itself − in which the executive branch amasses power and undermines democratic processes and institutions − remains poorly understood. We seek to shed light on the underlying mechanisms by studying democratic near misses: cases in which a period of autocratic governance is quickly reversed or full backsliding is prevented at the last minute. Building on the literature on near misses in sociotechnical systems such as nuclear power plants, we adapt the drift-to-danger model to the study of democratic systems. Two key findings emerge: First, democratic backsliding is often triggered by political elites pushing the boundaries of their power by violating norms, which are crucial yet vulnerable safeguards for democracy. Second, democratic backsliding is unpredictable and non-linear, being driven by the interaction between political elites and the public. Norm-violating elites may feel legitimized by a supportive public that sees norm violations as justified. At the same time, political elites may signal that norm-violating behaviour is acceptable, potentially leading the public to adopt anti-democratic beliefs and behaviours. We identify risk factors that make norm violations more likely and outline behavioural sciences-based interventions to address these violations.

Boosts and nudges are two separate types of behavioral public policies, distinguished by the mechanisms through which they operate. We investigated whether this theoretical distinction translates into different effects when instances of these policy types are implemented in the context of energy consumption. In a long-term field randomized controlled trial, we competitively tested boosts against nudges. We found that boosts outperform nudges throughout a seven-month period in a student dormitory setting – both in terms of accumulated energy savings, as well as in keeping consumption consistently low during the experimental period. Furthermore, we explored the processes behind the boosts and nudges through a number of mechanistic markers and showed that the tested interventions indeed are instances of the respective types.

Safety villages are interventions that aim to boost children's knowledge and behaviour regarding risk-taking behaviours and their consequences via an experiential learning approach. In safety villages, children experience scenarios involving risks that resemble real-life situations. We investigated the extent to which desirable learning outcomes from a single-session safety village visit are visible outside the safety village context. In a well-powered quasi-experimental preregistered field study, we compared students (aged 11–13) who received experiential safety education to a control group of students who had not yet received the education on three important learning outcomes: Knowledge-application, risk-taking behaviour and general risk-taking tendencies. Data were collected outside of the safety village environment, before or after the visit, and without explicit reminders of the visit. Results show students who received experiential safety education outperformed those who did not yet receive experiential education on knowledge-application and reduced risk-taking behaviours. We found no differences on general risk-taking tendencies. These results show a single visit to a safety village visit can reduce risk-taking of risks that were experienced in the village, but not general risk-taking tendencies. Theoretical and policy implications are discussed.

Companies face increasing pressure to adopt social responsibility initiatives while simultaneously providing shareholder value. However, consumers may respond negatively to ‘win-win’ initiatives that benefit society while bringing financial gain to the corporation, producing a backlash effect. Previous researchers have attributed this backlash effect to the violation of a communal relationship norm that companies trigger in consumers when communicating their win-win initiatives. We propose the alternative hypothesis that the backlash derives from people's deception aversion. We find evidence supporting deception aversion in three preregistered studies showing that companies are evaluated negatively when their actions differ from those implied by their stated prosocial policy and not, as predicted by the communal norm violation hypothesis, when they merely earn a profit. Our results suggest that companies should not fear that earning a profit from prosocial activities will carry reputational risk, so long as they are transparent.

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.

We provide behavioral insights into the economic substitution phenomenon among front-loaded and back-loaded tax-sheltered savings plans. We conduct three behavioral studies with adult Canadian participants to show experimentally that substitution can occur and to explain why substitution can occur. The first study shows that participants transfer savings from a front-loaded plan to a back-loaded plan when the latter becomes available, consistent with a substitution effect. The second study examines how participants trade-off two unique features of back-loaded and front-loaded savings plans. Our results indicate that participants favor the back-loaded tax feature and a variable contribution limit (offered in a front-loaded plan). As participants prefer one feature from each type of plan, this finding can help explain why substitution occurs. The third study provides participants a categorization task with various household budgeting items, including savings items. Results show that 68.1% of participants categorize multiple tax-sheltered savings plans in the same mental account, again consistent with a substitution effect under a budget constraint. As both tax-sheltered savings plans in Canada are used for different purposes, this finding shows that participants tend not to distinguish between the purpose of saving in each account, consistent with a substitution phenomenon.

Pro-environmental behavior, including waste sorting and recycling, involves a combination of future-oriented (futureness) and other-oriented (otherness) attributes. Inspired by the perspective of intergenerational choice, this work explores whether eliciting concerns for future others could increase public support for recycling policy and recycling behavior. Study 1 consisted of an online random controlled trial and a laboratory experiment. In Study 1A (N = 400), future other-concern was primed using a static text manipulation, whereas in Study 1B (N = 192), a dynamic virtual manipulation was employed. The results showed that people in the conditions that elicited future other-concern reported greater household recycling intentions and more actual recycling behavior than those in the control conditions. Study 2A (N = 467) and Study 2B (N = 600) generalized this effect on the acceptance of the ‘Certain Time Certain Place’ waste sorting policy in China. Consistent with the intergenerational choice model, envisioning the future of subsequent generations is more impactful in gaining policy approval than merely envisioning a future time. These findings provide a new method for promoting public policy approval and recycling behavior, suggesting that people could become environmentally friendly when they are guided to consider future others.

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.

This study examines how beliefs interact with heterogeneous donation preferences in determining people's donation decisions and choices of revision and observability. We conducted an online experiment eliciting participants’ first-order beliefs, that is, beliefs about an average donor's contribution, with the opportunity of being recognized. We also provided the opportunity for donation revision to a group of randomly selected participants. Our study results show that people's first-order beliefs are positively correlated with their willingness to donate and their actual donations. Moreover, first-order beliefs also interact with people's heterogeneous donation preferences in jointly determining their decisions of donation revision and observability – their tendency to opt in for public recognition. Donors with low first-order beliefs and high donation preferences are most likely to opt in for recognition, but they are unlikely to revise their donations. Donors with high first-order beliefs and low donation preferences are most likely to revise their donations, but they are less likely to choose to be recognized. Donors with low first-order beliefs and low donation preferences display the lowest tendency toward revision and observability.

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.

Dark patterns that manipulate consumer behaviour are now a pervasive feature of digital markets. Depending on the choice architecture utilised, they can affect the perception, behaviour and purchasing patterns of online consumers. Using a novel empirical design, we find strong evidence that individuals across all groups are susceptible to dark patterns, and only weak evidence that user susceptibility is materially affected by commonly used general proxies for consumer vulnerability (such as income, educational attainment or age). Our conclusions provide empirical support for broad restrictions on the use of dark patterns, such as those contained in the EU’s Digital Services Act, that protect all consumer groups. Our study also finds that added friction, in the form of required payment action following successful deployment of dark patterns, reduces their effectiveness. This insight highlights the instances in which dark patterns would be most effective – when no further action is required by the user. Consumer vulnerability is therefore more pronounced when dealing with online providers who store users’ payment details and can rely on a ‘single click’ to complete the purchase.

Many foodborne illness outbreaks originate in food service establishments. We tested two behavioural interventions designed to improve the duration and quality of handwashing. We ran a three-armed parallel trial in a laboratory kitchen, from 7 March to 27 May 2022. Participants were n = 195 workers who handle food. We randomly allocated participants to three groups: Timer – tap-mounted timer that counted seconds while participants washed their hands; Precommitment – agreed to five statements on good hand hygiene before attending the kitchen; and Control. Participants completed a food preparation task under time pressure. Cameras focused on the sink captured handwashing. Outcome measures were number of times participants washed their hands; number of times they washed their hands using soap; number of times they washed using soap and washed the backs of their hands; and mean duration of handwashing attempts using soap. Participants in Timer washed their hands for 1.9 s longer on average than Control (β = 2.20, 95% CI = 0.34-4.06, p = 0.021). Participants in Precommitment washed their hands for 2.5 s longer on average than Control (β = 2.30, 95% CI = 0.33-4.27, p = 0.022). We found no statistically significant differences on any other outcome measure.

Meat-based food production has a detrimental impact on the environment and health. In response, Veganuary (an international non-profit organisation) encourages people to go vegan each January. We investigated the effects of a Veganuary campaign in workplace cafeterias which increased the availability and salience of plant-based products. We conducted an interrupted time series analysis on a large dataset from a UK catering company, which comprised 2,255,404 meals sold between 2016 and 2022, with Veganuary activity starting from 2019. Analysis indicated that Veganuary activity had a positive effect on sales of vegan products in 2020, 2021 and 2022, estimated at an initial increase of 86–113% in the proportion of weekly sales (relative to the baseline, depending on year). The effects of the 2020 and 2021 campaigns were still present – at approximately one third of their initial magnitude – one year following the campaigns. There was a positive effect on vegetarian products in 2019, 2021 and 2022; initial effects were smaller – 23–79% – due to higher levels of pre-campaign consumption. The effects of the 2019 and 2021 campaigns endured, with a small impact present after one year for 2019 and six months for 2021.