Behavioral scientists have begun to research ‘sludge,’ excessive frictions that make it harder for people to do what they want to do. Friction is also an important concept in transaction-cost economics. Nevertheless, sludge has been discussed without explicit referral to transaction costs. Several questions arise from this observation. Is the analogy to friction used differently in both literatures? If so, what are the key differences? If not, should we develop the concept of sludge when the well-established literature on transaction costs already exists? This conceptual article shows that sludge and transaction costs are related, but distinct, concepts, and that the literature on sludge can benefit from incorporating elements from transaction-cost research. For example, we suggest defining sludge as aspects of the choice architecture that lead to the experience of costs, organize sludges using a typology inspired by the transaction-cost literature, highlight specificity, uncertainty, and frequency as important determinants of the ‘sludginess’ of choice architecture, and show that sludge audits can be conducted using methods developed in the transaction-cost literature.

Nudge plus is a modification of the toolkit of behavioral public policy. It incorporates an element of reflection – the plus – into the delivery of a nudge, either blended in or made proximate. Nudge plus builds on recent work combining heuristics and deliberation. It may be used to design prosocial interventions that help preserve the autonomy of the agent. The argument turns on seminal work on dual systems, which presents a subtler relationship between fast and slow thinking than commonly assumed in the classic literature in behavioral public policy. We review classic and recent work on dual processes to show that a hybrid is more plausible than the default-interventionist or parallel-competitive framework. We define nudge plus, set out what reflection could entail, provide examples, outline causal mechanisms, and draw testable implications.

Policy decisions have vast consequences, but there is little empirical research on how best to communicate underlying evidence to decision-makers. Groups in diverse fields (e.g., education, medicine, crime) use brief, graphical displays to list policy options, expected outcomes and evidence quality in order to make such evidence easy to assess. However, the understanding of these representations is rarely studied. We surveyed experts and non-experts on what information they wanted and tested their objective comprehension of commonly used graphics. A total of 252 UK residents from Prolific and 452 UK What Works Centre users interpreted the meaning of graphics shown without labels. Comprehension was low (often below 50%). The best-performing graphics combined unambiguous metaphorical shapes with color cues and indications of quantity. The participants also reported what types of evidence they wanted and in what detail (e.g., subgroups, different outcomes). Users particularly wanted to see intervention effectiveness and quality, and policymakers also wanted to know the financial costs and negative consequences. Comprehension and preferences were remarkably consistent between the two samples. Groups communicating evidence about policy options can use these results to design summaries, toolkits and reports for expert and non-expert audiences.

The COVID-19 pandemic has forced governments around the world into drastic measures without the normal evidence base or analyses of consequences. We present a quantitative model that can be used to rapidly assess the introduction and interaction of nonpharmaceutical infection prevention measures (NPI) both in rapid a priori predictions and in real-world a posteriori evaluations. Two of the most popular NPIs are imposing minimum physical interpersonal distancing and the use of face coverings. The success of both measures is highly dependent on the behavior of the public. However, there is very little published information about the interactions between distance, mask wearing, and the behavioral adaptations that they are likely to generate. We explore the relation between these two fundamental NPIs and the behavioral responses that they may induce, considering both risk compensation and social norms enhancement. At present, we do not have the necessary information to parameterize our model to a sufficient degree to generate quantitative, immediately applicable, advice, but we explore a vast parameter space and illustrate how the consequences of such measures can range from highly beneficial to paradoxically harmful in plausible real situations.

Both theory on motivational crowding and recent empirical evidence suggest that nudging may sometimes backfire and actually crowd out prosocial behavior, due to decreased intrinsic motivation and warm glow. In this study, we tested this claim by investigating the effects of three types of nudges (default nudge, social norm nudge, and moral nudge) on donations to charity in a preregistered online experiment (N = 1098). Furthermore, we manipulated the transparency of the nudges across conditions by explicitly informing subjects of the nudges that were used. Our results show no indication that nudges crowd out prosocial behavior; instead, all three nudges increased donations. The positive effects of the nudges were driven by the subjects who did not perceive the nudges as attempts to manipulate their behavior, while donations among subjects who felt that the nudges were manipulative remained unaffected. Subjects’ self-reported happiness with their choice also remained unaffected. Thus, we find no indication that nudges crowded out warm glow when acting altruistically. Generally, our results are good news for the proponents of nudges in public policy, since they suggest that concerns about unintended motivational crowding effects on prosocial behavior have been overstated.

Recent surveys in China, South Korea, Brazil, South Africa, Russia, Australia, Italy, the UK, Canada, France, Germany, the USA, Japan, Hungary, and Denmark indicate that citizens generally are positive toward state nudging. However, less is known about differences in the support for nudging across socio-demographics and political party preferences, a research gap recently identified in the literature. This article investigates the relationship between the support for nudging and trust in public institutions through a population-representative survey in Sweden. It also analyzes differences in the support for nudging across political party preferences in two ideological dimensions: the economic left-right and cultural GAL-TAN spectra. Data were collected in December 2017 through a custom web survey, using Reisch and Sunstein's (2016) questionnaire. The respondents (N = 1032) were representative of the adult population with regard to gender, age, education, job sector, household income, living region, and political party preference. Sweden was found to belong to the cautiously pronudge nations (along with Japan, Hungary, and Denmark), contrary to hypotheses in previous research. Differences in the support for nudging were found along the economic left-right and GAL-TAN spectra. Individual nudges’ variation in support, polarization, and politicization are analyzed and discussed.

Surveys based on self-reported hygiene-relevant routine behaviors have played a crucial role in policy responses to the COVID-19 pandemic. In this article, using anchoring to test validity in a randomized controlled survey experiment during the COVID-19 pandemic, we demonstrate that asking people to self-report on the frequency of routine behaviors are prone to significant measurement error and systematic bias. Specifically, we find that participants across age, gender, and political allegiance report higher (lower) frequencies of COVID-19-relevant behaviors when provided with a higher (lower) anchor. The results confirm that such self-reports should not be regarded as behavioral data and should primarily be used to inform policy decisions if better alternatives are not available. To this end, we discuss the use of anchoring as a validity test relative to self-reported behaviors as well as viable alternatives to self-reports when seeking to behaviorally inform policy decisions.

Criticisms of nudging suggest that nudges infringe on decision makers’ autonomy. Yet, little empirical research has explored whether people who are subjected to nudges agree. In three between-group experiments (N = 2083), we subject participants to contrasting choice architectures and measure experiences of autonomy, choice-satisfaction, perceived threat to freedom of choice, and objection to the choice architecture. Participants who received a prosocial opt-out default nudge made more prosocial choices but did not report lower autonomy or choice satisfaction than participants in opt-in default or active-choice conditions. This was the case even when the presence of the nudge was disclosed, and when monetary choice stakes were introduced. With monetary choice stakes, participants perceived the threat to freedom of choice as slightly higher in the nudge condition than in the other conditions, but objection to the choice architecture did not differ between the conditions. Taken together, our results suggest that default nudges are less manipulative and autonomy-infringing than sometimes feared. We recommend that policymakers include measures of choice experiences when testing out new interventions.

Do policymaker perceptions reflect actual citizen needs? A vast literature has explored the extent to which policy is responsive to public opinion, but there is little systematic work on policymaker perceptions of social problems. We quantify social problems with a unique dataset of the number of phone calls placed by citizens to a free service that connects Michigan residents to service providers. We combine these data with a survey of local policymakers’ perceptions of social problems facing their own city shows, consistent with theories of bounded rationality, that policymakers use heuristics to make judgments about the extent of constituent needs in their city, and that policymaker perceptions reflect the prevalence of needs. However, partisan perceptions of needs diverge, with Democrats consistently perceiving greater needs than Republicans. There is no evidence that policy activity on the needs in the sample is responsive to constituent needs. We conclude with implications for theories of policy making and avenues for future research.

The Internet is gaining relevance as a platform where extremist organizations seek to recruit new members. For this preregistered study, we developed and tested a novel online game, Radicalise, which aims to combat the effectiveness of online recruitment strategies used by extremist organizations, based on the principles of active psychological inoculation. The game “inoculates” players by exposing them to severely weakened doses of the key techniques and methods used to recruit and radicalize individuals via social media platforms: identifying vulnerable individuals, gaining their trust, isolating them from their community and pressuring them into committing a criminal act in the name of the extremist organization. To test the game's effectiveness, we conducted a preregistered 2 × 2 mixed (pre–post) randomized controlled experiment (n = 291) with two outcome measures. The first measured participants’ ability and confidence in assessing the manipulativeness of fictitious WhatsApp messages making use of an extremist manipulation technique before and after playing. The second measured participants’ ability to identify what factors make an individual vulnerable to extremist recruitment using 10 profile vignettes, also before and after playing. We find that playing Radicalise significantly improves participants’ ability and confidence in spotting manipulative messages and the characteristics associated with vulnerability.

A growing body of evidence shows that politicians use motivated reasoning to fit evidence with prior beliefs. In this, they are not unlike other people. We use survey experiments to reaffirm prior work showing that politicians, like the public they represent, engage in motivated reasoning. However, we also show that politicians are more resistant to debiasing interventions than others. When required to justify their evaluations, politicians rely more on prior political attitudes and less on policy information, increasing the probability of erroneous decisions. The results raise the troubling implication that the specialized role of elected officials makes them more immune to the correction of biases, and in this way less representative of the voters they serve when they process policy information.

In a large study that involved 2637 participants recruited from a representative UK and US sample, we tested the influence of four behavioural interventions (versus control) on a range of behaviours important for reducing the spread of COVID-19 a day after the interventions were administered. Even if people largely complied with social distancing measures, our analyses showed that for certain subgroups of the population the interventions made a positive difference. More specifically, for those who started practising social distancing relatively recently, an information-based intervention increased general compliance with social distancing and reduced both the number of times people went out and the number of hours they spent outside. However, for people who started practising social distancing relatively early, the interventions tended to backfire and, in some cases, reduced compliance with social distancing. Overall, this research has various policy implications and shows that, although behavioural interventions can positively impact compliance with social distancing, their effect may depend on personal circumstances.

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.

The behavioral sciences were there at the beginning of the systematic study of climate change. However, in the ensuing quarter century, they largely faded from view, during which time public discourse and policy evolved without them. That disengagement and the recent reengagement suggest lessons for the future role of the behavioral sciences in climate science and policy. Looking forward, the greatest promise lies in projects that make behavioral science integral to climate science by: (1) translating behavioral results into the quantitative estimates that climate analyses need; (2) making climate research more relevant to climate-related decisions; and (3) treating the analytical process as a behavioral enterprise, potentially subject to imperfection and improvement. Such collaborations could afford the behavioral sciences more central roles in setting climate-related policies, as well as implementing them. They require, and may motivate, changes in academic priorities.

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.

In this paper, we critically review three assumptions that govern the debate on the legitimacy of nudging interventions as a policy instrument: (1) nudges may violate autonomous decision-making; (2) nudges lend themselves to easy implementation in public policy; and (3) nudges are a simple and effective mean for steering individual choice in the right direction. Our analysis reveals that none of these assumptions are supported by recent studies entailing unique insights into nudging from three disciplinary outlooks: ethics, public administration and psychology. We find that nudges are less of a threat to autonomous choice than critics sometimes claim, making them ethically more legitimate than often assumed. Nonetheless, because their effectiveness is critically dependent on boundary conditions, their implementation is far from easy. The findings of this analysis thus suggest new opportunities for identifying when and for whom nudge interventions are preferable to more conventional public policy arrangements.

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.

Times of emergency often serve as triggers for the creation of new policy. Such policies may involve restriction of human rights, and various mechanisms can be used to mitigate the severity of such restrictions. One such mechanism is the temporary measure. A series of three experiments examined the potential of temporary measures for increasing the likelihood of approval of rights-restricting policy and the role of time – both prospectively and retrospectively – in the willingness to restrict human rights. We find that behavioural examination confirms the concerns expressed in the literature regarding temporary legislation. Participants asked to approve a rights-restricting policy were more willing to approve a temporary measure when it was presented as a compromise, and they were more willing to extend a rights-restricting policy when it had previously been implemented. These findings indicate a possible slippery slope effect in temporary legislation: policymakers might be persuaded to approve measures they would not otherwise approve when those measures are temporary or when they have been previously approved by others.

Financial incentives are often designed to benefit from behavioral insights. Individuals’ preferences for such behaviorally inspired incentives are rarely studied, nor is the role played by the behavioral insights that motivated them. This study aimed to let individuals design their own incentives (i.e., tailored incentives) and to explore which individual characteristics are associated with these preferences for tailored incentives. A sample of students (n = 182) tailored hypothetical incentives for visiting the gym. Incentives could be tailored by: (1) committing personal funds; (2) picking weekly payouts (increasing or decreasing); and (3) introducing payout risk while increasing value. Afterwards, (inter alia) loss aversion, probability weighting, time discounting, present bias, cognitive reflection and trait self-control were measured. A large majority indicated being willing to deposit their own money, and only very few individuals selected risky incentives. These heterogeneous preferences for financial incentives are poorly predicted by the individual characteristics measured (i.e., economic preferences and psychological traits). These results suggest that preferences for tailored incentives could be studied as input for the design of financial incentives. However, it is unclear whether tailoring incentives improves cost-effectiveness, as the lack of association between tailored incentives and the behavioral insights that motivate them has multiple conflicting interpretations.

Millions of Europeans use online platforms with almost blind trust that the platforms operate in the interests of the consumer. However, the presentation of search results, transparency about contractual parties and the publication of user reviews that contribute to the value of online platforms in Europe's Single Digital Market also pose significant risks regarding consumer protection and market competition. The current study investigates how enhanced information transparency in online platforms might affect consumers’ trust in online activities and choice behaviour. Following an exploratory qualitative study, three online discrete-choice experiments were conducted with representative samples of 1200 respondents in each of four countries: Germany, Poland, Spain and the UK. The objective of the experiments was to test whether increased transparency in the presentation of online search information, details of contractual entities and the implications for consumer protection and user reviews and ratings would affect consumers’ choices. The results show that increased online transparency increases the probability of product selection. A comparison across the four countries found that the similarities in responses to online transparency were far greater than the differences. The findings are discussed in relation to the biases and heuristics identified in behavioural science. In conclusion, recommendations are made to increase online transparency, which the empirical evidence of this study shows would benefit both users and platform operators.