Diverse ontogenies of reciprocal and prosocial behavior: cooperative development in Fiji and the United States

The social learning and development of intra- and inter-ethnic sharing norms in the Congo Basin: A registered report protocol

Compared to other species, the extent of human cooperation is unparalleled. Such cooperation is coordinated between community members via social norms. Developmental research has demonstrated that very young children are sensitive to social norms, and that social norms are internalized by middle childhood. Most research on social norm acquisition has focused on norms that modulated intra-group cooperation. Yet around the world, multi-ethnic communities also cooperate, and this cooperation is often shaped by distinct inter-group social norms. In the present study, we will investigate whether inter-ethnic and intra-ethnic social norm acquisition follows the same, or distinct, developmental trajectories. Specifically, we will work with BaYaka foragers and Bandongo fisher-farmers who inhabit multi-ethnic villages in the Republic of the Congo. In these villages, inter-ethnic cooperation is regulated by sharing norms. Through interviews with adult participants, we will provide the first descriptive account of the timing and mechanism by which BaYaka and Bandongo learn to share with out-group members. Children (5–17 years) and adults (17+ years) will also participate in a modified Dictator Game to investigate the developmental trajectories of children’s intra- and inter-ethnic sharing choices. Based on our ethnographic knowledge of the participating communities, we predict that children’s intra-ethnic sharing choices in the Dictator Game will match those of adults at an earlier age than their inter-ethnic sharing choices. We will analyze our data using logistic Bayesian modelling.

The Origins and Psychology of Human Cooperation

Humans are an ultrasocial species. This sociality, however, cannot be fully explained by the canonical approaches found in evolutionary biology, psychology, or economics. Understanding our unique social psychology requires accounting not only for the breadth and intensity of human cooperation but also for the variation found across societies, over history, and among behavioral domains. Here, we introduce an expanded evolutionary approach that considers how genetic and cultural evolution, and their interaction, may have shaped both the reliably developing features of our minds and the well-documented differences in cultural psychologies around the globe. We review the major evolutionary mechanisms that have been proposed to explain human cooperation, including kinship, reciprocity, reputation, signaling, and punishment; we discuss key culture-gene coevolutionary hypotheses, such as those surrounding self-domestication and norm psychology; and we consider the role of religions and marriage systems. Empirically, we synthesize experimental and observational evidence from studies of children and adults from diverse societies with research among nonhuman primates.

Social norms and cultural diversity in the development of third-party punishment

Human cooperation is probably supported by our tendency to punish selfishness in others. Social norms play an important role in motivating third-party punishment (TPP), and also in explaining societal differences in prosocial behaviour. However, there has been little work directly linking social norms to the development of TPP across societies. In this study, we explored the impact of normative information on the development of TPP in 603 children aged 4-14, across six diverse societies. Children began to perform TPP during middle childhood, and the developmental trajectories of this behaviour were similar across societies. We also found that social norms began to influence the likelihood of performing TPP during middle childhood in some of these societies. Norms specifying the punishment of selfishness were generally more influential than norms specifying the punishment of prosocial behaviour. These findings support the view that TPP of selfishness is important in all societies, and its development is shaped by a shared psychology for responding to normative information. Yet, the results also highlight the important role that children's prior knowledge of local norms may play in explaining societal variation in the development of both TPP and prosociality.

Normative foundations of reciprocity in preschoolers

Reciprocity has been suggested to represent a crucial normative principle for humans. The current study aimed to investigate the normative foundations of reciprocity and the development of a reciprocity norm in young children. To this end, we presented 3- to 6-year-olds with three conditions. In one condition, a protagonist reciprocated sharing a large proportion of resources. In another condition, a protagonist reciprocated sharing a small proportion of resources. In a third condition, a protagonist did not reciprocate sharing a large proportion by giving rather few resources and, thus, violated a reciprocity norm. Results show that 5- and 6-year-olds endorse compliance with a reciprocity norm, which is reflected in their evaluations of the protagonists and their spontaneous verbal affirmation of reciprocal behavior. In contrast, 3- and 4-year-olds exclusively valued general prosociality, neglecting reciprocity. This indicates that children acquire a norm of reciprocity during the course of the preschool period.

Considerations of Mutual Exchange in Prosocial Decision-Making

Research using economic decision-making tasks has established that direct reciprocity plays a role in prosocial decision-making: people are more likely to help those who have helped them in the past. However, less is known about how considerations of mutual exchange influence decisions even when the other party’s actions are unknown and direct reciprocity is therefore not possible. Using a two-party economic task in which the other’s actions are unknown, Study 1 shows that prosociality critically depends on the potential for mutual exchange; when the other person has no opportunity to help the participant, prosocial behavior is drastically reduced. In Study 2, we find that theories regarding the other person’s intentions influence the degree of prosociality that participants exhibit, even when no opportunity for direct reciprocity exists. Further, beliefs about the other’s intentions are closely related to one’s own motivations in the task. Together, the results support a model in which prosociality depends on both the social conditions for mutual exchange and a mental model of how others will behave within these conditions, which is closely related to knowledge of the self.

Modeling social norms increasingly influences costly sharing in middle childhood

Prosocial and normative behavior emerges in early childhood, but substantial changes in prosocial behavior in middle childhood may be due to it becoming integrated with children's understanding of what is normative. Here we show that information about what is normative begins influencing children's costly sharing in middle childhood in a sample of 6- to 11-year-old German children. Information about what is normative was most influential when indicating what was "right" (i.e., "The right thing is to choose this"). It was less influential when indicating what was prescribed by a rule (i.e., "There is a rule that says to choose this") or when it indicated what the majority of people do (i.e., "Most people choose this"). These findings support the idea that middle childhood is when social norms begin to shape children's costly sharing and provide insight into the psychological foundations of the relationship between norms and prosocial behavior.