Pat Barclay

Interpersonal contact is essential for cooperation and care, but it also provides a route for pathogen transmission between individuals. Hence, a key challenge for social organisms involves maintaining beneficial social contact while also limiting exposure to infection risks. Existing proposals suggest that this trade-off is guided by the interpersonal value of specific social targets. In addition, ecological and cultural factors including historical pathogen prevalence, individualism-collectivism, tightness-looseness, and relational mobility might also shape how people avoid pathogens. To test whether and how infection-risky social contact varies with individual-level interpersonal value and these societal-level factors, we collected data from 61 societies (n = 42,756). Participants were randomly assigned to imagine targets who varied in interpersonal value, then rated their comfort with infection-risky contact with that target (e.g., drinking from the same water bottle) and whether they would touch the target when greeting them. In all societies, participants were more comfortable with infection-risky contact and more likely to engage in physical contact during greetings with targets of higher interpersonal value. Such associations varied only modestly across societies. Notably, the associations between infection-risky contact and societal-level factors depended on target interpersonal value and were concentrated among high-value targets – contact was lower where historical pathogen prevalence and tightness were greater, and higher where individualism and relational mobility were greater. These findings suggest that infection-risky contact is primarily guided by the value of social targets, with ecological and cultural factors playing a lesser role.

Interpersonal contact is essential for cooperation and care, but it also provides a route for pathogen transmission between individuals. Hence, a key challenge for social organisms involves maintaining beneficial social contact while also limiting exposure to infection risks. Existing proposals suggest that this trade-off is guided by the interpersonal value of specific social targets. In addition, ecological and cultural factors, including historical pathogen prevalence, individualism-collectivism, tightness–looseness, and relational mobility, might also shape how people avoid pathogens. To test whether and how infection-risky social contact varies with individual-level interpersonal value and these societal-level factors, we collected data from 47,756 participants across 61 societies. Participants were randomly assigned to picture a social target - either a friend, acquaintance, stranger, or enemy. They then rated their comfort with infection-risky contact with that target (e.g., drinking from the same water bottle) and whether they would touch the target when greeting them. In all societies, participants were more comfortable with infection-risky contact and more likely to engage in physical contact during greetings with targets of higher interpersonal value. Such associations varied only modestly across societies. Notably, the associations between infection-risky contact and societal-level factors depended on target interpersonal value and were concentrated among high-value targets—contact was lower where historical pathogen prevalence and tightness were greater and higher where individualism and relational mobility were greater. These findings suggest that infection-risky contact is primarily guided by the value of social targets, with ecological and cultural factors playing a lesser role.

We extend Ko & Neuberg’s framework by integrating biological markets. Because many affordances are provided by others, they follow market dynamics based on partner-choice processes (partner availability, switching costs, and actor value) – which shift across environments and life stages. These shifts reshape market composition and affordances, generating testable predictions about who perceives opportunities, when and why, and how these shape behavioral strategies.

The widely used painkiller acetaminophen (also known as paracetamol) has been found to blunt various emotional states and evaluations, possibly through the same mechanisms by which it dulls the affective component of physical pain. However, there are limited investigations into the behavioral consequences of blunting emotions pharmacologically. Previous work has demonstrated that acetaminophen lessens risk perception and increases risk-taking in tasks with low-stakes incentives, though no studies have tested its effects in fear-inducing contexts that require evaluating safety risk. As fear promotes behaviors that keep us safe, dampening fear could alter how people respond to threatening situations. To test this possibility, 260 participants were given either 1000 mg of acetaminophen or placebo capsules prior to a frightening virtual reality plank walk at extreme heights. Compared to the placebo group, those on acetaminophen took less time to step onto the plank, walked across it faster, and had lower heart rates. These findings suggest that acetaminophen may reduce protective behaviors associated with the fear response, raising potential safety concerns for everyday users.

Why do we care so much for friends-much more than one might predict from reciprocity alone? According to a recent theory, organisms who cooperate with each other come to have a stake in each other's well-being: A good cooperator is worth protecting-even anonymously if necessary-so they can be available to cooperate in the future. Here, we present three experiments showing that reciprocity creates a stake in a partner's well-being, such that people are willing to secretly pay to protect good cooperative partners, if doing so keeps those partners available for future interaction. Participants played five rounds of a cooperative game (Prisoner's Dilemma) and then received an opportunity to help their partner, without the partner ever knowing. In Experiments 1 and 2, participants were more willing to help a cooperative partner if doing so kept that partner available for future rounds, compared to when the help simply raised the partner's earnings. This effect was specific to cooperative partners: The type of help mattered less for uncooperative partners or for recipients that participants did not directly interact with. In other words, an ongoing history of reciprocity gave people a stake in their partner's good condition but not their partner's payoff. Experiment 3 showed that participants had less stake in their partners if those partners could be easily replaced by another cooperator. These findings show that reciprocity and stake are not separate processes. Instead, even shallow reciprocity creates a deeper stake in a partner's well-being, including a willingness to help with zero expectation of recognition. Future work should examine how one's stake in partners is affected by ecological factors that affect the gains of cooperation and the ease of finding new partners. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

According to current theory and experiments, cooperation is more likely to evolve when organisms can choose to replace uncooperative partners with cooperative ones. However, there is a downside to this partner choice: when partners can be easily replaced, organisms have less stake in their partners’ welfare and will therefore be less likely to help keep those partners alive and well enough to reciprocate. Here, I present a mathematical model showing that when a third party is present, organisms will provide more observable help to their partners (reciprocity/signalling-based helping), but less anonymous help that would keep that partner in good condition (stake-based helping). The net effect of partner choice depends on the relative strength of these two factors: partner choice has a more positive effect if interactions are short (i.e. less stake), when observers judge based on observed helping (i.e. reputation matters), and when one can have multiple cooperative partners at the same time. These results show the importance of differentiating between helping that relies on observation (e.g. reciprocity and signalling), helping that requires no observation (e.g. kinship and stake), and how the two types interact.

Moral licensing occurs when someone who initially behaves morally subsequently acts less morally. We apply reputation-based theories to predict when and why it occurs. As pre-registered, we predicted: (1) being observed would be associated with larger licensing effects and (2) unambiguous outcomes would have smaller licensing effects. In a multi-level meta-analysis of 115 experiments ( N = 21,770), moral licensing was stronger when participants were observed ( g = 0.65) than unobserved ( g = 0.13). After accounting for publication bias with robust Bayesian meta-analysis, there was moderate evidence for licensing when participants were observed ( g = 0.51; BF ₁₀ = 9.14), but moderate evidence against licensing when unobserved (Hedge’s g = −0.01; BF ₁₀ = 0.11). Ambiguity did not moderate moral licensing. These findings suggest that moral licensing is elicited through interpersonal motives, clarify when licensing (vs. consistency) occurs, and explain why many online studies failed to replicate. Evidence for intrapsychic motives is inconclusive.

How do people evaluate victims who advertise their victim status? Because such broadcasting can elicit sympathy and support, we propose that declining to broadcast serves as a costly act of modesty: one is withholding a fact about oneself that could garner resources and benefits. We suggest that individuals who are less demanding are more willing to forego these benefits, such that broadcasting victimization serves as a signal of demandingness that can carry reputation costs. Across seven primary studies and one supplementary study (total n = 6,360), we find that people who broadcast (versus “bury”, i.e., decline to advertise) their victim status are perceived as less modest, more demanding, and less moral and desirable interaction partners. Broadcasting carries reputation costs even when it can function to alert others of an ongoing threat (Study 2) and when broadcasting would elicit sympathy (Studies 3a-b). However, we find some evidence that the reputation costs are mitigated when broadcasting is directed at fewer, closer ties (versus a broader audience) (Study 4). Finally, we ask whether the reputation consequences of broadcasting versus burying are attenuated in contexts where broadcasting is a less informative signal of demandingness. Interestingly, participants do not see broadcasting as a less informative signal of demandingness when victimization is more “discoverable” (i.e., observable to others absent broadcasting) (Study 5). Yet the reputation costs of broadcasting (versus burying) indeed decline when participants receive direct information about a victim’s level of demandingness, suggesting that attributions of demandingness underlie these reputation costs (Study 6).

Moral licensing occurs when someone who initially behaves morally, subsequently acts less morally. We apply reputation-based theories to predict when and why it occurs. As pre-registered, we predicted: (1) being observed would be associated with larger licensing effects, and (2) unambiguous outcomes would have smaller licensing effects. In a multi-level meta-analysis of 115 experiments (N = 21,770), moral licensing was stronger when participants were observed (g = 0.65) than unobserved (g = 0.13). After accounting for publication bias with robust Bayesian meta-analysis, there was moderate evidence for licensing when participants were observed (g = 0.51; BF10 = 9.14), but moderate evidence against licensing when unobserved (Hedge’s g = -0.01; BF10 = 0.11). Ambiguity did not moderate moral licensing. These findings suggest that moral licensing is elicited through interpersonal motives, clarify when licensing (vs. consistency) occurs, and explain why many online studies failed to replicate. Evidence for intrapsychic motives is inconclusive.

Punishment plays a role in human cooperation, but it is costly. Prior research shows that people are more cooperative when they expect to receive negative feedback for non-cooperation, even in the absence of costly punishment, which would have interesting implications for theory and applications. However, based on theories of habituation and cue-based learning, we propose that people will learn to ignore expressions of disapproval that are not clearly associated with material costs or benefits. To test this hypothesis, we conducted a between-subjects, 40-round public goods game (i.e. much longer than most studies), where participants could respond to others’ contributions by sending numerical disapproval messages, paying to reduce others’ earnings, or neither. Consistent with previous results, we observed steadily increasing contributions in the costly punishment condition. In contrast, contributions declined after the early rounds in the expressed disapproval condition, and were eventually no higher than the basic control condition with neither costly punishment nor disapproval ratings. In other words, costless disapproval may temporarily increase cooperation, but the effects fade. We discuss the theoretical and applied implications of our findings, including the unexpectedly high levels of cooperation in a second control condition.