In this paper, I pick up on an important theme in Mario Rizzo’s work: that rationality should be understood more broadly than the rational choice model as learning to adjust behaviour in the light of experience and the mistakes that it yields. In particular, I focus on learning-by-doing (LBD). I argue in the first part of the paper that it should be regarded as one of the central insights in economics, alongside those that are more usually recognised like the gains from trade and the importance of unintended consequences. I use Smith and Hirschman’s discussion of LBD to ground this claim. In the second part of the paper, I turn to the determinants of LBD in teams. I argue that the key rule or constitutional/policy design question is how best to embrace the diversity that is central to LBD within teams without this undermining the social origins of co-operation in teams.

We have previously argued thatbehavioral scientists have been testing and advocating individualistic (i-frame) solutions to policy problems that have systemic (s-frame) causes and require systemic solutions. Here, we consider the implications of adopting an s-frame approach for research. We argue that an s-frame approach will involve addressing different types of questions, which will, in turn, require a different toolbox of research methods.

There are both negative and positive stereotypes about public sector workers. Most studies focus on negative stereotypes, like the idea that public servants are lazy. We, however, do the opposite. We focus on a positive stereotype: public sector workers are seen as caring and helpful. We test the effects of positive stereotypes on the quality of public service delivery. Using a pre-registered audit experiment in elderly care in the Netherlands and Belgium, we find that activating a pro-social stereotype does not affect the outcome of public service quality in terms of response rate and information provision. However, it does improve the bureaucratic process: public sector workers are friendlier toward citizens. They say around 12% more ‘thank you’ in their replies. Moreover, the citizens’ gender affects the response rate: female citizens receive around 10% more replies. Concluding, we show that positive stereotyping can improve parts of the quality of public service delivery but not all.

To improve public health and promote environmental sustainability, widespread dietary changes are necessary in high-income countries. However, adopting and maintaining dietary goals is challenging and requires repeated self-regulation. Effective public policies can facilitate healthy food choices and reduce the likelihood of goal failure. This study examines the relationship between individuals’ dietary goal failures and their acceptance of public food policies, using data from an experience-sampling study (Ni = 409 and Nobs = 6,447). Regression analyses revealed that participants who experienced more frequent dietary goal failures were generally less accepting of health-promoting food policies and perceived them as less effective. Additionally, perceived policy effectiveness positively predicted policy acceptance. Exploratory analyses showed that the negative relationship between dietary goal failure and food policy acceptance varied depending on the type of intervention (pull policies vs push policies) and the location of food selections (home vs out-of-home). Notably, we found a positive relationship between dietary goal failure and acceptance of pull policies for food selections made out-of-home. These findings highlight the importance of better understanding the complex interplay between public policy attitudes, the food environment and adherence to dietary goals.

To what extent can the harms of misinformation be mitigated by relying on nudges? Prior research has demonstrated that non-intrusive ‘accuracy nudges’ can reduce the sharing of misinformation. We investigate an alternative approach. Rather than subtly reminding people about accuracy, our intervention, indebted to research on the bystander effect, explicitly appeals to individuals' capacity to help solve the misinformation challenge. Our results are mixed. On the one hand, our intervention reduces the willingness to share and believe in misinformation fact-checked as false. On the other hand, it also reduces participants' willingness to share information that has been fact-checked as true and innocuous, as well as non-fact-checked information. Experiment 1 offers proof of concept; Experiment 2 tests our intervention with a more realistic mix of true and false social media posts; Experiment 3 tests our interventions alongside an accuracy nudge. The effectiveness of our intervention at reducing willingness to share misinformation remains consistent across experiments; meta-analysis reveals that our treatment reduced willingness to share false content across experiments by 20% of a scale point on a six-point scale. We do not observe the accuracy nudge reducing willingness to share false content. Taken together, these results highlight the advantages and disadvantages of accuracy nudges and our more confrontational approach.

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.

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.

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.

This study investigates the impacts of behavioral finance on stock market volatility. The primary aims are to explain the reasons behind changes in the S&P 500 price within the context of behavioral finance and to analyze investor behavior in response to these changes. To achieve this, the research employs time-series analysis over a 10-year period, focusing on the S&P 500, real interest rates, consumer confidence, market volatility and credit default swaps while considering the effects of behavioral biases. The findings reveal several significant correlations: rising real interest rates negatively affect stocks due to loss aversion and sentiment. Conversely, higher consumer confidence tends to positively influence the stock market, driven by herding behavior and optimism. Additionally, market volatility shows a negative correlation with the S&P 500, influenced by risk aversion, recency bias and herding behavior. Moreover, an increase in credit default swap rates leads to stock market declines, primarily influenced by risk perception, loss aversion and herding behavior.

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.

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.

Consequentialist theories of the behavioral state are largely grounded in satisfying self-interested preferences through policies that employ choice architecture and related strategies to encourage rational decision-making. Even when allowing for free choice, however, this stance tends to be characterized by a paternalistic ‘view from nowhere’ that may not fully accommodate a plurality of values. Alternative approaches such as contractarianism position policy in the context of marketplace exchange, bolstered by shared beliefs in the legitimacy of social institutions. Yet this view may not sufficiently consider issues of asymmetric access, or ideological frames that do not see these institutions as legitimate. To address these deficits, we propose the value of a dialogical approach to behavioral public policy that facilitates collaborative engagement and behavioral justice to redress asymmetries and inequities through a more discursive approach, which builds on practices employed by design for public policy. In so doing, this political theory suggests an actionable counterpoint to paternalistic and competition-based conceptions of the State to address frame plurality and increase the potential for system equity.

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.

Similarly to other domains of the social sciences, behavioural science has grappled with a crisis concerning the effect sizes of research findings. Different solutions have been provided to answer this challenge. This paper will discuss analytical strategies developed in the context of computational social science, namely causal tree and forest, that will benefit behavioural scientists in harnessing heterogeneity of treatment effects in RCTs. As a mixture of theoretical and data-driven approaches, these techniques are well suited to exploit the rich information provided by large studies conducted using RCTs. We discuss the characteristics of these methods and their methodological rationale and provide simulations to illustrate their use. We simulate two scenarios of RCTs-generated data and explore the heterogeneity of treatment effects using causal tree and causal forest methods. Furthermore, we outlined a potential theoretical use of these techniques to enrich behavioural science ecological validity by introducing the notion of behavioural niche.

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.

Compliance with hygiene and other safety measures in the workplace was an important component of society's strategy for reducing infections at the onset of the COVID-19 pandemic, in particular before vaccinations were widely available. We report the results of a field trial of well-established behavioural interventions (social norms, pledging and messenger effects) we implemented to improve compliance with such measures in an occupational setting. We use daily reports of own and other's behaviour to assess the effects of these interventions and supplement these subjective (self-reported) measures with objective data on hand sanitiser usage. The behavioural interventions tested have statistically significant but quantitatively moderate effects on subjective compliance measures and minimal effects on hand sanitiser usage. All effects of our interventions are short-term in nature and dissipate shortly after implementation. Our findings thus provide at most weak support for the notion that typical behavioural interventions can help support compliance with infection prevention measures in the workplace.