Eric J. Pedersen

Do humans really punish altruistically? A closer look

Some researchers have proposed that natural selection has given rise in humans to one or more adaptations for altruistically punishing on behalf of other individuals who have been treated unfairly, even when the punisher has no chance of benefiting via reciprocity or benefits to kin. However, empirical support for the altruistic punishment hypothesis depends on results from experiments that are vulnerable to potentially important experimental artefacts. Here, we searched for evidence of altruistic punishment in an experiment that precluded these artefacts. In so doing, we found that victims of unfairness punished transgressors, whereas witnesses of unfairness did not. Furthermore, witnesses’ emotional reactions to unfairness were characterized by envy of the unfair individuals selfish gains rather than by moralistic anger towards the unfair behaviour. In a second experiment run independently in two separate samples, we found that previous evidence for altruistic punishment plausibly resulted from affective forecasting error—that is, limitations on humans’ abilities to accurately simulate how they would feel in hypothetical situations. Together, these findings suggest that the case for altruistic punishment in humans—a view that has gained increasing attention in the biological and social sciences—has been overstated.

What Are Punishment and Reputation for

Why did punishment and the use of reputation evolve in humans? According to one family of theories, they evolved to support the maintenance of cooperative group norms; according to another, they evolved to enhance personal gains from cooperation. Current behavioral data are consistent with both hypotheses (and both selection pressures could have shaped human cooperative psychology). However, these hypotheses lead to sharply divergent behavioral predictions in circumstances that have not yet been tested. Here we report results testing these rival predictions. In every test where social exchange theory and group norm maintenance theory made different predictions, subject behavior violated the predictions of group norm maintenance theory and matched those of social exchange theory. Subjects do not direct punishment toward those with reputations for norm violation per se; instead, they use reputation self-beneficially, as a cue to lower the risk that they personally will experience losses from defection. More tellingly, subjects direct their cooperative efforts preferentially towards defectors they have punished and away from those they haven’t punished; they avoid expending punitive effort on reforming defectors who only pose a risk to others. These results are not consistent with the hypothesis that the psychology of punishment evolved to uphold group norms. The circumstances in which punishment is deployed and withheld–its circuit logic–support the hypothesis that it is generated by psychological mechanisms that evolved to benefit the punisher, by allowing him to bargain for better treatment.

Variation in oxytocin receptor gene (OXTR) polymorphisms is associated with emotional and behavioral reactions to betrayal

Variations in the gene that encodes the oxytocin receptor (OXTR) have been associated with many aspects of social cognition as well as several prosocial behaviors. However, potential associations of OXTR variants with reactions to betrayals of trust while cooperating for mutual benefit have not yet been explored. We examined how variations in 10 single-nucleotide polymorphisms on OXTR were associated with behavior and emotional reactions after a betrayal of trust in an iterated Prisoners Dilemma Game. After correction for multiple testing, one haplotype (C-rs9840864, T-rs2268494) was significantly associated with faster retaliation post-betrayal-an association that appeared to be due to this haplotypes intermediate effect of exacerbating peoples anger after they had been betrayed. Furthermore, a second haplotype (A-rs237887, C-rs2268490) was associated with higher levels of post-betrayal satisfaction, and a third haplotype (G-rs237887, C-rs2268490) was associated with lower levels of post-betrayal satisfaction.

Conciliatory gestures promote forgiveness and reduce anger in humans.

Significance Conflict is a common feature of social life among group-living animals, but many social relationships often retain value even after conflicts have occurred. Consequently, natural selection has likely endowed humans and other animal species with cognitive systems that motivate reconciliation with interaction partners that they perceive as valuable and nonthreatening, notwithstanding prior conflict. In a large sample of people who had recently been harmed by an interaction partner, we found that conciliatory gestures, such as apologies and offers of compensation, accelerated forgiveness and reduced anger toward transgressors, largely by altering victims’ perceptions of their transgressors’ relationship value and exploitation risk. These results give insight into the design logic behind the cognitive systems that motivate human postconflict reconciliation. Conflict is an inevitable component of social life, and natural selection has exerted strong effects on many organisms to facilitate victory in conflict and to deter conspecifics from imposing harms upon them. Like many species, humans likely possess cognitive systems whose function is to motivate revenge as a means of deterring individuals who have harmed them from harming them again in the future. However, many social relationships often retain value even after conflicts have occurred between interactants, so natural selection has very likely also endowed humans with cognitive systems whose function is to motivate reconciliation with transgressors whom they perceive as valuable and nonthreatening, notwithstanding their harmful prior actions. In a longitudinal study with 337 participants who had recently been harmed by a relationship partner, we found that conciliatory gestures (e.g., apologies, offers of compensation) were associated with increases in victims’ perceptions of their transgressors’ relationship value and reductions in perceptions of their transgressors’ exploitation risk. In addition, conciliatory gestures appeared to accelerate forgiveness and reduce reactive anger via their intermediate effects on relationship value and exploitation risk. These results strongly suggest that conciliatory gestures facilitate forgiveness and reduce anger by modifying victims’ perceptions of their transgressors’ value as relationship partners and likelihood of recidivism.

Reassessing intertemporal choice: human decision-making is more optimal in a foraging task than in a self-control task.

Many contemporary concerns (e.g., addiction, failure to save) can be viewed as intertemporal choice problems in which the consequences of choices are realized at different times. In some laboratory paradigms used to study intertemporal choice, non-human animals demonstrate a preference for immediacy (impulsive choice) that results in failures to maximize the amount of reward received. There is evidence, however, suggesting that such non-optimal impulsive choice may be due to a mismatch between the standard presentation of options in the laboratory (e.g., a “larger-later” and a “smaller-sooner” option) and the way that options occur in natural settings (e.g., foraging). We present evidence that human impulsive choice is similarly affected: in two experiments, decisions were more optimal when options were presented in a format sharing features with the evolutionarily important problem of foraging compared to when options were presented in the standard format. These findings suggest a more nuanced view of intertemporal choice and support the adoption of ideas from foraging theory into the study of human decision making.

Testing the arousal hypothesis of neonatal imitation in infant rhesus macaques

Neonatal imitation is the matching of (often facial) gestures by newborn infants. Some studies suggest that performance of facial gestures is due to general arousal, which may produce false positives on neonatal imitation assessments. Here we examine whether arousal is linked to facial gesturing in newborn infant rhesus macaques (Macaca mulatta). We tested 163 infants in a neonatal imitation paradigm in their first postnatal week and analyzed their lipsmacking gestures (a rapid opening and closing of the mouth), tongue protrusion gestures, and yawn responses (a measure of arousal). Arousal increased during dynamic stimulus presentation compared to the static baseline across all conditions, and arousal was higher in the facial gestures conditions than the nonsocial control condition. However, even after controlling for arousal, we found a condition-specific increase in facial gestures in infants who matched lipsmacking and tongue protrusion gestures. Thus, we found no support for the arousal hypothesis. Consistent with reports in human newborns, imitators’ propensity to match facial gestures is based on abilities that go beyond mere arousal. We discuss optimal testing conditions to minimize potentially confounding effects of arousal on measurements of neonatal imitation.

Experience with anonymous interactions reduces intuitive cooperation

The Social Heuristics Hypothesis claims that cooperation is intuitive because it is positively reinforced in everyday life, where behaviour typically has reputational consequences1,2. Consequently, participants will cooperate in anonymous laboratory settings unless they either reflect on the one-shot nature of the interaction or learn through experience with such settings that cooperation does not promote self-interest. Experiments reveal that cognitive-processing manipulations (which increase reliance on either intuition or deliberation) indeed affect cooperation3, but may also introduce confounds4,5. Here, we elide the interpretation issues created by between-subjects designs in showing that people are less cooperative over time in laboratory paradigms in which cooperation cannot promote self-interest, but are just as cooperative over time in paradigms that have the potential to promote self-interest. Contrary to previous findings6,7, we find that cooperation is equally intuitive for men and women: unilateral giving did not differ across gender at the first study session, and decreased equally for both genders across sessions.Reputational concerns reinforce the instinct to cooperate in social situations. McAuliffe et al. find that cooperative habits can be overturned in one-shot anonymous interactions, when people learn that defection will not damage their self-interest.

The unresponsive avenger: More evidence that disinterested third parties do not punish altruistically

Many social scientists believe humans possess an evolved motivation to punish violations of norms—including norm violations that do not harm them directly. However, most empirical evidence for so-called altruistic punishment comes from experimental economics games that create experimental demand for third-party punishment, raising the possibility that the third-party punishment uncovered in these experiments has been motivated by a desire to appear concerned about social norms rather than by actual concern about upholding them. Here we present the results of five experiments in which we used an aggression paradigm to contrast second-party and third-party punishment with minimal experimental demand. We also summarize the results of these experiments meta-analytically. We found robust evidence that participants who were insulted by a stranger experienced anger and punished the insulter. To a lesser degree, participants who witnessed a friend receive an insult also became angry and punished the insulter. In contrast, we found robust evidence that participants who witnessed a stranger receive an insult did not punish the insulter, although they did experience modest amounts of anger. In only one experiment did we find any punishment on behalf of a stranger, and this result could plausibly be explained by the desire to escape the moral censure of other bystanders. Our results suggest that experimental designs that rely on demand-laden methods to test hypotheses about third-party punishment may have overstated the case for the existence of this trait.