Evidence for third-party mediation but not punishment in Mentawai justice

Harmless bodily pleasures are moralized because they are perceived as reducing self-control and cooperativeness

Why do many people morally condemn unrestrained indulgence in bodily pleasures-such as gluttony, masturbation, and drinking alcohol-even when these behaviors do not harm others? Leading theories of moral cognition claim that these puritanical moral judgments are independent of cognitive adaptations for reciprocal cooperation. In five pre-registered experiments (N > 3000), we test an alternative hypothesis: that puritanical moral judgments emerge from perceptions that bodily pleasures indirectly facilitate free-riding by impairing self-control. In Studies 1 and 2a-b, participants judged that targets who increased (vs. decreased) their non-other-harming sex, food, alcohol, and inactivity would become more likely to cheat, an effect mediated by the perception that they would become less self-controlled. In Study 3, participants judged that relaxing regulations on sex, food, and alcohol in a village would decrease self-control and cooperation in the village, although they judged enforcing puritanical prohibitions even more negatively. In Study 4, participants expected that, in a scientific experiment, a treatment group made to increase their consumption of bodily pleasures would become less self-controlled and more likely to cheat than a psychologically similar control group. Across all studies, the perception that indulgence reduces self-control and cooperativeness was associated with the moral condemnation of harmless bodily pleasures. This provides support for the idea that some purity violations, although they do not directly harm other people, may be morally condemned because they activate cognitive systems designed for reciprocal cooperation.

Beyond punishment: psychological foundations of restorative interventions

Work on the psychology of justice has largely focused on punishment. However, punishment is not our only strategy for dealing with conflict. Rather, emerging work suggests that people often respond to transgressions by compensating victims, involving third-party mediators, and engaging in forgiveness. These responses are linked in that they are involved in more restorative than retributive justice practices: they center victims as well as (or instead of) perpetrators and can help repair fractured relationships. Work with non-human animals echoes these findings: reconciliation and intervention by third parties play a key role in conflict management across taxa. In this review, we focus on these restorative interventions, with the aim of painting a more complete picture of the psychology of justice.

The motive cocktail in altruistic behaviors

Prosocial motives such as social equality and efficiency are key to altruistic behaviors. However, predicting the range of altruistic behaviors in varying contexts and individuals proves challenging if we limit ourselves to one or two motives. Here we demonstrate the numerous, interdependent motives in altruistic behaviors and the possibility to disentangle them through behavioral experimental data and computational modeling. In one laboratory experiment (N = 157) and one preregistered online replication (N = 1,258), across 100 different situations, we found that both third-party punishment and third-party helping behaviors (that is, an unaffected individual punishes the transgressor or helps the victim) aligned best with a model of seven socioeconomic motives, referred to as a motive cocktail. For instance, the inequality discounting motives imply that individuals, when confronted with costly interventions, behave as if the inequality between others barely exists. The motive cocktail model also provides a unified explanation for the differences in intervention willingness between second parties (victims) and third parties, and between punishment and helping.

Cross-societal variation in norm enforcement systems

Across human societies, people are sometimes willing to punish norm violators. Such punishment can take the form of revenge from victims, seemingly altruistic intervention from third parties, or legitimized sanctioning from institutional representatives. Although prior work has documented cross-cultural regularities in norm enforcement, substantial variation exists in the prevalence and forms of punishment across societies. Such cross-societal variation may arise from universal psychological mechanisms responding to different socio-ecological conditions, or from cultural evolutionary processes, resulting in different norm enforcement systems. To date, empirical evidence from comparative studies across diverse societies has remained disconnected, owing to a lack of interdisciplinary integration and a prevalent tendency of empirical studies to focus on different underpinnings of variation in norm enforcement. To provide a more complete view of the shared and unique aspects of punishment across societies, we review prior research in anthropology, economics and psychology, and take a first step towards integrating the plethora of socio-ecological and cultural factors proposed to explain cross-societal variation in norm enforcement. We conclude by discussing how future cross-societal research can use diverse methodologies to illuminate key questions on the domain-specificity of punishment, the diversity of tactics supporting social norms, and their role in processes of norm change. This article is part of the theme issue 'Social norm change: drivers and consequences'.

The science of justice: The neuropsychology of social punishment

The social punishment (SP) of norm violations has received much attention across multiple disciplines. However, current models of SP fail to consider the role of motivational processes, and none can explain the observed behavioral and neuropsychological differences between the two recognized forms of SP: second-party punishment (2PP) and third-party punishment (3PP). After reviewing the literature giving rise to the current models of SP, we propose a unified model of SP which integrates general psychological descriptions of decision-making as a confluence of affect, cognition, and motivation, with evidence that SP is driven by two main factors: the amount of harm (assessed primarily in the salience network) and the norm violator's intention (assessed primarily in the default-mode and central-executive networks). We posit that motivational differences between 2PP and 3PP, articulated in mesocorticolimbic pathways, impact final SP by differentially impacting the assessments of harm and intention done in these domain-general large-scale networks. This new model will lead to a better understanding of SP, which might even improve forensic, procedural, and substantive legal practices.

Children endorse deterrence motivations for third-party punishment but derive higher enjoyment from compensating victims

Children's punishment behavior may be driven by both retribution and deterrence, but the potential primacy of either motive is unknown. Moreover, children's punishment enjoyment and compensation enjoyment have never been directly contrasted. Here, British, Colombian, and Italian 7- to 11-year-old children (N = 123) operated a Justice System in which they viewed different moral transgressions in Minecraft, a globally popular video game, either face-to-face with an experimenter or over the internet. Children could respond to transgressions by punishing transgressors and compensating victims. The purpose of the system was framed in terms of retribution, deterrence, or compensation between participants. Children's performance, endorsement, and enjoyment of punishment and compensation were measured, along with their endorsement of retribution versus deterrence as punishment justifications, during and/or after justice administration. Children overwhelmingly endorsed deterrence over retribution as their punishment justification irrespective of age. When asked to reproduce the presented frame in their own words, children more reliably reproduced the deterrence frame rather than the retribution frame. Punishment enjoyment decreased while compensation enjoyment increased over time. Despite enjoying compensation more, children preferentially endorsed punishment over compensation, especially with increasing age and transgression severity. Reported deterrent justifications, superior reproduction of deterrence framing, lower enjoyment of punishment than of compensation, and higher endorsement of punishment over compensation together suggest that children felt that they ought to mete out punishment as a means to deter future transgressions. Face-to-face and internet-mediated responses were not distinguishable, supporting a route to social psychology research with primary school-aged children unable to physically visit labs.

Norm violations and punishments across human societies

Punishments for norm violations are hypothesised to be a crucial component of the maintenance of cooperation in humans but are rarely studied from a comparative perspective. We investigated the degree to which punishment systems were correlated with socioecology and cultural history. We took data from the Standard Cross-Cultural Sample database and coded ethnographic documents from a sample of 131 largely non-industrial societies. We recorded whether punishment for norm violations concerned adultery, religion, food, rape or war cowardice and whether sanctions were reputational, physical, material or execution. We used Bayesian phylogenetic regression modelling to test for culture-level covariation. We found little evidence of phylogenetic signals in evidence for punishment types, suggesting that punishment systems change relatively quickly over cultural evolutionary history. We found evidence that reputational punishment was associated with egalitarianism and the absence of food storage; material punishment was associated with the presence of food storage; physical punishment was moderately associated with greater dependence on hunting; and execution punishment was moderately associated with social stratification. Taken together, our results suggest that the role and kind of punishment vary both by the severity of the norm violation, but also by the specific socio-economic system of the society.

Preverbal infants' reactions to third-party punishments and rewards delivered toward fair and unfair agents

Rewarding individuals who distribute resources fairly and punishing those who distribute resources unfairly may be very important actions for fostering cooperation. This study investigated whether 9-month-olds have some expectations concerning punishments and rewards that follow distributive actions. Infants were shown simple animations and were tested using the violation-of-expectation paradigm. In Experiment 1, we found that infants looked longer when they saw a bystander delivering a corporal punishment to a 'fair distributor,' who distributed some windfall resources equally to the possible recipients, rather than to an 'unfair distributor,' who distributed the resources unequally. This pattern of looking times was reversed when, in Experiment 2, punishments were replaced with rewards. These findings suggest an early emergence of expectations about punishing and rewarding actions in third-party contexts, and they help to evaluate competing claims about the origins of a sense of fairness.

The evolution of peace

While some species have affiliative and even cooperative interactions between individuals of different social groups, humans are alone in having durable, positive-sum, interdependent relationships across unrelated social groups. Our capacity to have harmonious relationships that cross group boundaries is an important aspect of our species' success, allowing for the exchange of ideas, materials, and ultimately enabling cumulative cultural evolution. Knowledge about the conditions required for peaceful intergroup relationships is critical for understanding the success of our species and building a more peaceful world. How do humans create harmonious relationships across group boundaries and when did this capacity emerge in the human lineage? Answering these questions involves considering the costs and benefits of intergroup cooperation and aggression, for oneself, one's group, and one's neighbor. Taking a game theoretical perspective provides new insights into the difficulties of removing the threat of war and reveals an ironic logic to peace - the factors that enable peace also facilitate the increased scale and destructiveness of conflict. In what follows, I explore the conditions required for peace, why they are so difficult to achieve, and when we expect peace to have emerged in the human lineage. I argue that intergroup cooperation was an important component of human relationships and a selective force in our species history beginning at least 300 thousand years. But the preconditions for peace only emerged in the past 100 thousand years and likely coexisted with intermittent intergroup violence which would have also been an important and selective force in our species' history.

Subjective selection and the evolution of complex culture

Why is culture the way it is? Here I argue that a major force shaping culture is subjective (cultural) selection, or the selective retention of cultural variants that people subjectively perceive as satisfying their goals. I show that people evaluate behaviors and beliefs according to how useful they are, especially for achieving goals. As they adopt and pass on those variants that seem best, they iteratively craft culture into increasingly effective-seeming forms. I argue that this process drives the development of many cumulatively complex cultural products, including effective technology, magic and ritual, aesthetic traditions, and institutions. I show that it can explain cultural dependencies, such as how certain beliefs create corresponding new practices, and I outline how it interacts with other cultural evolutionary processes. Cultural practices everywhere, from spears to shamanism, develop because people subjectively evaluate them to be effective means of satisfying regular goals.