Megastudies improve the impact of applied behavioural science.

Policy-makers are increasingly turning to behavioural science for insights about how to improve citizens' decisions and outcomes1. Typically, different scientists test different intervention ideas in different samples using different outcomes over different time intervals2. The lack of comparability of such individual investigations limits their potential to inform policy. Here, to address this limitation and accelerate the pace of discovery, we introduce the megastudy-a massive field experiment in which the effects of many different interventions are compared in the same population on the same objectively measured outcome for the same duration. In a megastudy targeting physical exercise among 61,293 members of an American fitness chain, 30 scientists from 15 different US universities worked in small independent teams to design a total of 54 different four-week digital programmes (or interventions) encouraging exercise. We show that 45% of these interventions significantly increased weekly gym visits by 9% to 27%; the top-performing intervention offered microrewards for returning to the gym after a missed workout. Only 8% of interventions induced behaviour change that was significant and measurable after the four-week intervention. Conditioning on the 45% of interventions that increased exercise during the intervention, we detected carry-over effects that were proportionally similar to those measured in previous research3-6. Forecasts by impartial judges failed to predict which interventions would be most effective, underscoring the value of testing many ideas at once and, therefore, the potential for megastudies to improve the evidentiary value of behavioural science.

A 680,000-person megastudy of nudges to encourage vaccination in pharmacies.

Encouraging vaccination is a pressing policy problem. To assess whether text-based reminders can encourage pharmacy vaccination and what kinds of messages work best, we conducted a megastudy. We randomly assigned 689,693 Walmart pharmacy patients to receive one of 22 different text reminders using a variety of different behavioral science principles to nudge flu vaccination or to a business-as-usual control condition that received no messages. We found that the reminder texts that we tested increased pharmacy vaccination rates by an average of 2.0 percentage points, or 6.8%, over a 3-mo follow-up period. The most-effective messages reminded patients that a flu shot was waiting for them and delivered reminders on multiple days. The top-performing intervention included two texts delivered 3 d apart and communicated to patients that a vaccine was "waiting for you." Neither experts nor lay people anticipated that this would be the best-performing treatment, underscoring the value of simultaneously testing many different nudges in a highly powered megastudy.

Signing at the beginning versus at the end does not decrease dishonesty.

Honest reporting is essential for society to function well. However, people frequently lie when asked to provide information, such as misrepresenting their income to save money on taxes. A landmark finding published in PNAS [L. L. Shu, N. Mazar, F. Gino, D. Ariely, M. H. Bazerman, Proc. Natl. Acad. Sci. U.S.A. 109, 15197-15200 (2012)] provided evidence for a simple way of encouraging honest reporting: asking people to sign a veracity statement at the beginning instead of at the end of a self-report form. Since this finding was published, various government agencies have adopted this practice. However, in this project, we failed to replicate this result. Across five conceptual replications (n = 4,559) and one highly powered, preregistered, direct replication (n = 1,235) conducted with the authors of the original paper, we observed no effect of signing first on honest reporting. Given the policy applications of this result, it is important to update the scientific record regarding the veracity of these results.

The "hearts-and-minds frame": Not all i-frame interventions are ineffective, but education-based interventions can be particularly bad.

Pitting i-frame policies against s-frame policies inadvertently propagates a false dichotomy that fails to distinguish between effective i-frame policies that directly change behaviors and ineffective education-based i-frame policies that try to change people's hearts and minds. We argue that people's fixation on changing hearts and minds may be an obstacle for behavioral science in policy.

Willpower is a form of, but not synonymous with, self-control.

We build on Ainslie's discussion of willpower by highlighting another common misconception in the literature: the conflation of self-control and willpower. In our commentary, we identify this issue and discuss the importance of recognizing willpower not as synonymous with self-control, but rather as a subset of self-control. We describe a set of upstream strategies as more effective alternatives to willpower.

Going beyond the "self" in self-control: Interpersonal consequences of commitment strategies.

Commitment strategies are effective mechanisms individuals can use to overcome self-control problems. Across seven studies (and two supplemental studies), we explore the negative interpersonal consequences of commitment strategy choice and use. In Study 1, using an incentivized trust game, we demonstrate that individuals trust people who choose to use a commitment strategy less than those who choose to use willpower to achieve their goals. Study 2 shows this relationship holds across four domains and for integrity-based trust in particular. Study 3 provides evidence that it is the choice to use the strategy rather than strategy use itself that incurs this integrity penalty. In Studies 4-5b, we demonstrate that this effect is driven, at least in part, by the fact that people infer past performance from strategy choice. Finally, Study 6 provides evidence that people select commitment strategies more in private than in public, which is consistent with the notion that people anticipate the negative consequences of commitment strategy choice. Thus, we establish the role of willpower as a positive signal in impression formation as well as the negative interpersonal consequences of choosing to rely on external aides when faced with temptation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Conveying and detecting listening during live conversation.

Across all domains of human social life, positive perceptions of conversational listening (i.e., feeling heard) predict well-being, professional success, and interpersonal flourishing. However, a fundamental question remains: Are perceptions of listening accurate? Prior research has not empirically tested the extent to which humans can detect others' cognitive engagement (attentiveness) during live conversation. Across five studies (total N = 1,225), using a combination of correlational and experimental methods, we find that perceivers struggle to distinguish between attentive and inattentive conversational listening. Though people's listening fluctuated naturally throughout their conversations (people's minds wandered away from the conversation 24% of the time), they were able to adjust their listening in line with instructions and incentives-by either listening attentively, inattentively, or dividing their attention-and their conversation partners struggled to detect these differences. Specifically, speakers consistently overestimated their conversation partners' attentiveness-often believing their partners were listening when they were not. Our results suggest this overestimation is (at least partly) due to the largely indistinguishable behavior of inattentive and attentive listeners. It appears that people can (and do) divide their attention during conversation and successfully feign attentiveness. Overestimating others' attentiveness extended to third-party observers who were not immersed in the conversation, listeners who looked back on their own listening, and people interacting with partners who could not hear their words (but were incentivized to act like they could). Our work calls for a reexamination of a fundamental social behavior-listening-and underscores the distinction between feeling heard and being heard during live conversation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Reducing discrimination against job seekers with and without employment gaps.

Past research shows that decision-makers discriminate against applicants with career breaks. Career breaks are common due to caring responsibilities, especially for working mothers, thereby leaving job seekers with employment gaps on their résumés. In a preregistered audit field experiment in the United Kingdom (n = 9,022), we show that rewriting a résumé so that previously held jobs are listed with the number of years worked (instead of employment dates) increases callbacks from real employers compared to résumés without employment gaps by approximately 8%, and with employment gaps by 15%. A series of lab studies (an online pilot and two preregistered experiments; n = 2,650) shows that this effect holds for both female and male applicants-even when compared to applicants without employment gaps-as well as and for applicants with less and more total job experience. The effect is driven by making the applicant's job experience salient, not as a result of novelty or ease of reading.

What we can learn from five naturalistic field experiments that failed to shift commuter behaviour.

Across five field experiments with employees of a large organization (n = 68,915), we examined whether standard behavioural interventions ('nudges') successfully reduced single-occupancy vehicle commutes. In Studies 1 and 2, we sent letters and emails with nudges designed to increase carpooling. These interventions failed to increase carpool sign-up or usage. In Studies 3a and 4, we examined the efficacy of other well-established behavioural interventions: non-cash incentives and personalized travel plans. Again, we found no positive effect of these interventions. Across studies, effect sizes ranged from Cohen's d = -0.01 to d = 0.05. Equivalence testing, using study-specific smallest effect sizes of interest, revealed that the treatment effects observed in four out of five of our experiments were statistically equivalent to zero (P < 0.04). The failure of these well-powered experiments designed to nudge commuting behaviour highlights both the difficulty of changing commuter behaviour and the importance of publishing null results to build cumulative knowledge about how to encourage sustainable travel.