A synthesis of evidence for policy from behavioural science during COVID-19.

Scientific evidence regularly guides policy decisions1, with behavioural science increasingly part of this process2. In April 2020, an influential paper3 proposed 19 policy recommendations ('claims') detailing how evidence from behavioural science could contribute to efforts to reduce impacts and end the COVID-19 pandemic. Here we assess 747 pandemic-related research articles that empirically investigated those claims. We report the scale of evidence and whether evidence supports them to indicate applicability for policymaking. Two independent teams, involving 72 reviewers, found evidence for 18 of 19 claims, with both teams finding evidence supporting 16 (89%) of those 18 claims. The strongest evidence supported claims that anticipated culture, polarization and misinformation would be associated with policy effectiveness. Claims suggesting trusted leaders and positive social norms increased adherence to behavioural interventions also had strong empirical support, as did appealing to social consensus or bipartisan agreement. Targeted language in messaging yielded mixed effects and there were no effects for highlighting individual benefits or protecting others. No available evidence existed to assess any distinct differences in effects between using the terms 'physical distancing' and 'social distancing'. Analysis of 463 papers containing data showed generally large samples; 418 involved human participants with a mean of 16,848 (median of 1,699). That statistical power underscored improved suitability of behavioural science research for informing policy decisions. Furthermore, by implementing a standardized approach to evidence selection and synthesis, we amplify broader implications for advancing scientific evidence in policy formulation and prioritization.

Initial impressions of compatibility and mate value predict later dating and romantic interest.

Romantic first impressions seem to linger, but why? Few studies have investigated how romantic desire during initial interactions predicts later relational outcomes (e.g., later romantic interest, contact attempts) using a design that can tease apart different possible mechanisms (e.g., mate value, selectivity, compatibility). Across three speed-dating studies (n = 559) with longitudinal follow-ups (including college and community samples, and a sample of men who date men), we investigated whether different components of initial romantic impressions predicted later romantic outcomes and relationship initiation. Using the social relations model, we partitioned initial desire at speed dating (determined from 6,600+ total dates) into partner effects (a date's consensual desirability, e.g., mate value), actor effects (a participant's general desirousness, e.g., selectivity), and relationship effects (a participant's unique liking for a date over and beyond partner and actor effects, e.g., compatibility) to predict later evaluations (romantic interest, physical attraction, and desire to know better) and behaviors (direct messaging and going on dates). Meta-analyses across the three studies showed that, across 6,100+ follow-up reports, partner and relationship effects were especially strong predictors of relationship initiation variables. Consistent with evolutionary models of human pair bonding, these findings suggest that both consensually desirable traits and unique impressions of compatibility have lingering effects on relationship development, even from the moment that two potential partners meet.

Machine learning uncovers the most robust self-report predictors of relationship quality across 43 longitudinal couples studies.

Given the powerful implications of relationship quality for health and well-being, a central mission of relationship science is explaining why some romantic relationships thrive more than others. This large-scale project used machine learning (i.e., Random Forests) to 1) quantify the extent to which relationship quality is predictable and 2) identify which constructs reliably predict relationship quality. Across 43 dyadic longitudinal datasets from 29 laboratories, the top relationship-specific predictors of relationship quality were perceived-partner commitment, appreciation, sexual satisfaction, perceived-partner satisfaction, and conflict. The top individual-difference predictors were life satisfaction, negative affect, depression, attachment avoidance, and attachment anxiety. Overall, relationship-specific variables predicted up to 45% of variance at baseline, and up to 18% of variance at the end of each study. Individual differences also performed well (21% and 12%, respectively). Actor-reported variables (i.e., own relationship-specific and individual-difference variables) predicted two to four times more variance than partner-reported variables (i.e., the partner's ratings on those variables). Importantly, individual differences and partner reports had no predictive effects beyond actor-reported relationship-specific variables alone. These findings imply that the sum of all individual differences and partner experiences exert their influence on relationship quality via a person's own relationship-specific experiences, and effects due to moderation by individual differences and moderation by partner-reports may be quite small. Finally, relationship-quality change (i.e., increases or decreases in relationship quality over the course of a study) was largely unpredictable from any combination of self-report variables. This collective effort should guide future models of relationships.

A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect.

We conducted a preregistered multilaboratory project (k = 36; N = 3,531) to assess the size and robustness of ego-depletion effects using a novel replication method, termed the paradigmatic replication approach. Each laboratory implemented one of two procedures that was intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a nonsignificant result (d = 0.06). Confirmatory Bayesian meta-analyses using an informed-prior hypothesis (δ = 0.30, SD = 0.15) found that the data were 4 times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring exclusion criteria) found a statistically significant effect (d = 0.08); Bayesian analyses showed that the data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants who reported more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation.

Dominant, open nonverbal displays are attractive at zero-acquaintance.

Across two field studies of romantic attraction, we demonstrate that postural expansiveness makes humans more romantically appealing. In a field study (n = 144 speed-dates), we coded nonverbal behaviors associated with liking, love, and dominance. Postural expansiveness-expanding the body in physical space-was most predictive of attraction, with each one-unit increase in coded behavior from the video recordings nearly doubling a person's odds of getting a "yes" response from one's speed-dating partner. In a subsequent field experiment (n = 3,000), we tested the causality of postural expansion (vs. contraction) on attraction using a popular Global Positioning System-based online-dating application. Mate-seekers rapidly flipped through photographs of potential sexual/date partners, selecting those they desired to meet for a date. Mate-seekers were significantly more likely to select partners displaying an expansive (vs. contractive) nonverbal posture. Mediation analyses demonstrate one plausible mechanism through which expansiveness is appealing: Expansiveness makes the dating candidate appear more dominant. In a dating world in which success sometimes is determined by a split-second decision rendered after a brief interaction or exposure to a static photograph, single persons have very little time to make a good impression. Our research suggests that a nonverbal dominance display increases a person's chances of being selected as a potential mate.

The Psychology of Close Relationships: Fourteen Core Principles.

Relationship science is a theory-rich discipline, but there have been no attempts to articulate the broader themes or principles that cut across the theories themselves. We have sought to fill that void by reviewing the psychological literature on close relationships, particularly romantic relationships, to extract its core principles. This review reveals 14 principles, which collectively address four central questions: (a) What is a relationship? (b) How do relationships operate? (c) What tendencies do people bring to their relationships? (d) How does the context affect relationships? The 14 principles paint a cohesive and unified picture of romantic relationships that reflects a strong and maturing discipline. However, the principles afford few of the sorts of conflicting predictions that can be especially helpful in fostering novel theory development. We conclude that relationship science is likely to benefit from simultaneous pushes toward both greater integration across theories (to reduce redundancy) and greater emphasis on the circumstances under which existing (or not-yet-developed) principles conflict with one another.

Is Romantic Desire Predictable? Machine Learning Applied to Initial Romantic Attraction.

Matchmaking companies and theoretical perspectives on close relationships suggest that initial attraction is, to some extent, a product of two people's self-reported traits and preferences. We used machine learning to test how well such measures predict people's overall tendencies to romantically desire other people (actor variance) and to be desired by other people (partner variance), as well as people's desire for specific partners above and beyond actor and partner variance (relationship variance). In two speed-dating studies, romantically unattached individuals completed more than 100 self-report measures about traits and preferences that past researchers have identified as being relevant to mate selection. Each participant met each opposite-sex participant attending a speed-dating event for a 4-min speed date. Random forests models predicted 4% to 18% of actor variance and 7% to 27% of partner variance; crucially, however, they were unable to predict relationship variance using any combination of traits and preferences reported before the dates. These results suggest that compatibility elements of human mating are challenging to predict before two people meet.

Leveling the Playing Field: Longer Acquaintance Predicts Reduced Assortative Mating on Attractiveness.

Clear empirical demonstrations of the theoretical principles underlying assortative mating remain elusive. This article examines a moderator of assortative mating--how well couple members knew each other before dating--suggested by recent findings related to market-based (i.e., competition) theories. Specifically, competition is pervasive to the extent that people achieve consensus about who possesses desirable qualities (e.g., attractiveness) and who does not. Because consensus is stronger earlier in the acquaintance process, assortative mating based on attractiveness should be stronger among couples who formed a relationship after a short period rather than a long period of acquaintance. A study of 167 couples included measures of how long partners had known each other before dating and whether they had been friends before dating, as well as coders' ratings of physical attractiveness. As predicted, couples revealed stronger evidence of assortative mating to the extent that they knew each other for a short time and were not friends before initiating a romantic relationship.

Low self-control promotes the willingness to sacrifice in close relationships.

Although previous theories and research have suggested that human behavior is automatically driven by selfish impulses (e.g., vengeance rather than forgiveness), the present research tested the hypothesis that in close relationships, people's impulsive inclination is to be prosocial and to sacrifice for their partner-to pursue the interests of the partner or of the relationship at some costs for the self. Results from four studies demonstrated that people with low self-control, relative to those with high self-control, reported greater willingness to sacrifice for their close others. Furthermore, Study 4 demonstrated that communal orientation was more strongly associated with sacrifice among participants with low self-control than participants with high self-control. This moderational pattern supports the hypothesis that communal orientation functions as a default approach to sacrifice in the context of close relationships. Taken together, these findings suggest that under certain crucial conditions in close relationships, gut-level impulses are more likely than deliberative considerations to promote prorelationship behavior.

A brief intervention to promote conflict reappraisal preserves marital quality over time.

Marital quality is a major contributor to happiness and health. Unfortunately, marital quality normatively declines over time. We tested whether a novel 21-min intervention designed to foster the reappraisal of marital conflicts could preserve marital quality in a sample of 120 couples enrolled in an intensive 2-year study. Half of the couples were randomly assigned to receive the reappraisal intervention in Year 2 (following no intervention in Year 1); half were not. Both groups exhibited declines in marital quality over Year 1. This decline continued in Year 2 among couples in the control condition, but it was eliminated among couples in the reappraisal condition. This effect of the reappraisal intervention on marital quality over time was mediated through reductions in conflict-related distress over time. This study illustrates the potential of brief, theory-based, social-psychological interventions to preserve the quality of intimate relationships over time.

The voodoo doll task: Introducing and validating a novel method for studying aggressive inclinations.

Aggression pervades modern life. To understand the root causes of aggression, researchers have developed several methods to assess aggressive inclinations. The current article introduces a new behavioral method-the voodoo doll task (VDT)-that offers a reliable and valid trait and state measure of aggressive inclinations across settings and relationship contexts. Drawing on theory and research on the law of similarity and magical beliefs (Rozin, Millman, & Nemeroff [1986], Journal of Personality and Social Psychology, 50, 703-712), we propose that people transfer characteristics of a person onto a voodoo doll representing that person. As a result, causing harm to a voodoo doll by stabbing it with pins may have important psychological similarities to causing actual harm to the person the voodoo doll represents. Nine methodologically diverse studies (total N = 1,376) showed that the VDT had strong reliability, construct validity, and convergent validity. Discussion centers on the importance of magical beliefs in understanding the causes of aggressive inclinations.

The social media discourse of engaged partisans is toxic even when politics are irrelevant.

Prevailing theories of partisan incivility on social media suggest that it derives from disagreement about political issues or from status competition between groups. This study-which analyzes the commenting behavior of Reddit users across diverse cultural contexts (subreddits)-tests the alternative hypothesis that such incivility derives in large part from a selection effect: Toxic people are especially likely to opt into discourse in partisan contexts. First, we examined commenting behavior across over 9,000 unique cultural contexts (subreddits) and confirmed that discourse is indeed more toxic in partisan (e.g. r/progressive, r/conservatives) than in nonpartisan contexts (e.g. r/movies, r/programming). Next, we analyzed hundreds of millions of comments from over 6.3 million users and found robust evidence that: (i) the discourse of people whose behavior is especially toxic in partisan contexts is also especially toxic in nonpartisan contexts (i.e. people are not politics-only toxicity specialists); and (ii) when considering only nonpartisan contexts, the discourse of people who also comment in partisan contexts is more toxic than the discourse of people who do not. These effects were not driven by socialization processes whereby people overgeneralized toxic behavioral norms they had learned in partisan contexts. In contrast to speculation about the need for partisans to engage beyond their echo chambers, toxicity in nonpartisan contexts was higher among people who also comment in both left-wing and right-wing contexts (bilaterally engaged users) than among people who also comment in only left-wing or right-wing contexts (unilaterally engaged users). The discussion considers implications for democratic functioning and theories of polarization.

Mate evaluation theory.

There are two unresolved puzzles in the literature examining how people evaluate mates (i.e., prospective or current romantic/sexual partners). First, compatibility is theoretically crucial, but attempts to explain why certain perceivers are compatible with certain targets have revealed small effects. Second, features of partners (e.g., personality, consensually rated attributes) affect perceivers' evaluations strongly in initial-attraction contexts but weakly in established relationships. Mate Evaluation Theory (MET) addresses these puzzles, beginning with the Social Relations Model postulate that all evaluative constructs (e.g., attraction, relationship satisfaction) consist of target, perceiver, and relationship variance. MET then explains how people draw evaluations from mates' attributes using four information sources: (a) shared evolved mechanisms and cultural scripts (common lens, which produces target variance); (b) individual differences that affect how a perceiver views all targets (perceiver lens, which produces perceiver variance); (c) individual differences that affect how a perceiver views some targets, depending on the targets' features (feature lens, which produces some relationship variance); and (d) narratives about and idiosyncratic reactions to one particular target (target-specific lens, which produces most relationship variance). These two distinct sources of relationship variance (i.e., feature vs. target-specific) address Puzzle #1: Previous attempts to explain compatibility used feature lens information, but relationship variance likely derives primarily from the (understudied) target-specific lens. MET also addresses Puzzle #2 by suggesting that repeated interaction causes the target-specific lens to expand, which reduces perceivers' use of the common lens. We conclude with new predictions and implications at the intersection of the human-mating and person-perception literatures. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

"Mostly White, heterosexual couples": Examining demographic diversity and reporting practices in relationship science research samples.

Social and personality psychologists aim to "understand individuals in their social contexts for the benefit of all people" (Society for Personality and Social Psychology, n.d.). Though this mission is admirable, value statements do little, on their own, to create an inclusive, high-quality science that benefits humanity broadly. In this research, we evaluate relationship science, a major subfield of social-personality psychology, illustrating both the unique diversity-relevant challenges faced by particular subfields and the barriers to inclusive and diverse research that are shared across research areas. Specifically, we examine the sample diversity and reporting practices of 1,762 studies published in eight mainstream psychology and relationships journals at two time points-(a) 1996-2000 and (b) 2016-2020-and center our analysis around five focal sample characteristics: gender, sexual orientation, regional context, socioeconomic status (SES), and race. We find that reporting practices and representation have not improved for some core demographic characteristics (e.g., socioeconomic status) and that even in domains for which reporting practices have improved (e.g., sexual orientation), reporting remains limited. Further, we find that reporting practices in relationship science frequently center Whiteness (e.g., "participants were mostly White"), obscure or overlook potential sexual orientation diversity (e.g., implying that individuals in man-woman dyads are "heterosexual"), and treat the United States as the contextual default (e.g., participants came from a "large Southeastern university"). In light of these findings, we offer recommendations that we hope will cultivate a more representative and inclusive discipline. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Connect or protect? Social class and self-protection in romantic relationships.

Lower SES (socioeconomic status) couples tend to face particular challenges in their relationships. Relative to higher SES couples, they are less likely to marry and more likely to divorce-but they do not value their romantic relationships any less. Drawing on risk regulation theory and theories of social class as culture, we suggest that lower SES individuals adapt to their more chronically precarious environments by prioritizing self-protection more than higher SES individuals do, but that the need to self-protect may undermine relationship satisfaction. We investigate these ideas across 3 studies, using cross-sectional, longitudinal, and daily-diary methods. Lower SES individuals were more self-protective, both in their thoughts about their relationship (Studies 2-3), and in the judgments they made about their partner's commitment level over 2 years (Study 1) and 2 weeks (Study 3). Self-protection, in turn, was associated with lower relationship satisfaction (Studies 2-3). However, lower SES individuals were only self-protective when feeling vulnerable in their relationships (Study 3). Taken together, these studies identify psychological mechanisms to explain why the structural challenges that lower SES individuals experience can make it more difficult to achieve satisfying relationships. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Interventions to reduce partisan animosity.

Rising partisan animosity is associated with a reduction in support for democracy and an increase in support for political violence. Here we provide a multi-level review of interventions designed to reduce partisan animosity, which we define as negative thoughts, feelings and behaviours towards a political outgroup. We introduce the TRI framework to capture three levels of intervention-thoughts (correcting misconceptions and highlighting commonalities), relationships (building dialogue skills and fostering positive contact) and institutions (changing public discourse and transforming political structures)-and connect these levels by highlighting the importance of motivation and mobilization. Our review encompasses both interventions conducted as part of academic research projects and real-world interventions led by practitioners in non-profit organizations. We also explore the challenges of durability and scalability, examine self-fulfilling polarization and interventions that backfire, and discuss future directions for reducing partisan animosity.

Outsourcing self-regulation.

Three studies demonstrate a novel phenomenon--self-regulatory outsourcing--in which thinking about how other people can be instrumental (i.e., helpful) for a given goal undermines motivation to expend effort on that goal. In Experiment 1, participants who thought about how their partner helped them with health goals (as opposed to career goals) planned to spend less time and effort on health goals in the upcoming week. This pattern was stronger for depleted participants than for nondepleted participants. In Experiment 2, participants who thought about how their partner helped them with academic-achievement goals procrastinated more, leaving themselves less time for an academic task, than did participants in two control conditions. This pattern was stronger for participants who were told that procrastinating would drain their resources for the academic task than for participants who were told that procrastinating would not drain their resources for that task. In Experiment 3, participants who decreased their effort after thinking of an instrumental significant other reported higher relationship commitment to that individual than did participants who did not decrease their effort. The possibility for shared (or transactive) self-regulation is discussed.

Language style matching predicts relationship initiation and stability.

Previous relationship research has largely ignored the importance of similarity in how people talk with one another. Using natural language samples, we investigated whether similarity in dyads' use of function words, called language style matching (LSM), predicts outcomes for romantic relationships. In Study 1, greater LSM in transcripts of 40 speed dates predicted increased likelihood of mutual romantic interest (odds ratio = 3.05). Overall, 33.3% of pairs with LSM above the median mutually desired future contact, compared with 9.1% of pairs with LSM at or below the median. In Study 2, LSM in 86 couples' instant messages positively predicted relationship stability at a 3-month follow-up (odds ratio = 1.95). Specifically, 76.7% of couples with LSM greater than the median were still dating at the follow-up, compared with 53.5% of couples with LSM at or below the median. LSM appears to reflect implicit interpersonal processes central to romantic relationships.

The effects of self-regulatory strength, content, and strategies on close relationships.

This article reviews the growing literature on the effects of self-regulatory strength (how much self-regulatory ability people have), self-regulatory content (the goals toward which people self-regulate), and self-regulatory strategies (the manner in which people self-regulate) on close relationships. The extant literature indicates that close relationships benefit when relationship partners (a) have greater versus less self-regulatory strength, (b) prioritize relationship-promotion goals versus self-protection goals, (c) facilitate versus obstruct each other's personal goal pursuits, (d) enact positive relationship behaviors using approach versus avoidance strategies, and (e) pursue shared goals using complementary versus similar regulatory focus strategies. Future research could fruitfully (a) delve deeper into the influences of self-regulatory content and strategies on relationships and (b) integrate multiple lines of research examining the effects of self-regulation on relationships.

Who are "We"? Couple Identity Clarity and Romantic Relationship Commitment.

This research introduces the construct of couple identity clarity-the extent to which an individual, as one of two partners in a romantic relationship, believes that the two of them know who they are as a couple. Cross-sectional (Studies 1-2), experimental (Study 3), and longitudinal (Study 4) studies supported the hypothesis that couple identity clarity is associated with higher commitment. Moreover, higher couple identity clarity, although related to actual agreement between partners on their identity as a couple, predicted commitment above and beyond agreement (Study 2)-as well as predicted reduced likelihood of relationship dissolution over a 9-month period (Study 4). Exploratory analyses revealed that successful conflict resolution may enhance couple identity clarity, in turn predicting commitment (Study 4). These studies highlight the importance of people's understanding of who they are as a couple and how this understanding shapes relationship persistence.