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Ontogeny of Prosocial Behavior Across Diverse Societies

Introduction

  • Humans are uniquely cooperative, but variation in cooperation exists across societies.

  • Analyzing the sources of this variation can illuminate the mechanisms supporting cooperation.

Objectives of the Study

  • To study the ontogeny of prosocial behavior among children and adults from different societies.

  • To investigate responses of 326 children (ages 3-14) and 120 adults from six different societies.

    • Societies include:

    • Aka: Nomadic hunter-gatherers in the Congo Basin

    • Himba: Semi-nomadic agro-pastoralists in Namibia

    • Shuar: Slash-and-burn horticulturalists in the Amazon

    • Martu: Sedentized foragers from Australia

    • Yasawa Island, Fiji: Marine forager-horticulturalists

    • Urban Americans: Residents of Los Angeles

Key Findings

Variation in Prosocial Behavior

  • Costly vs. Noncostly Prosocial Behavior:

    • When prosocial actions require personal cost, behavior declines as children approach middle childhood.

    • Conversely, when actions involve no personal sacrifice, prosocial responses steadily increase with age.

Cultural Norms and Social Contexts

  • Results suggest social norms significantly influence costly cooperation across diverse cultures.

  • The developmental transition into adult-like prosocial behavior varies among different societies, highlighting cultural effects.

Hypotheses Derived from Gene-Culture Coevolution

  1. Variability in prosocial behavior is more prominent in contexts with higher costs of cooperation.

  2. Children begin to acquire behavioral norms of their communities, affecting cooperation from a young age.

Developmental Pathway Investigated

  • Group-Specific Developmental Shifts:

    • Emergence of cost-related prosocial behavior occurs in middle childhood.

    • Children are especially sensitive to cultural influences regarding the willingness to help when it incurs costs.

Comparative Analysis of Adult Behavior

  • Adults from larger societies more inclined to punish selfishness and share resources, influenced by economic and demographic factors.

  • Cultural norms are presumed to adapt to the ecological and economic environment.

Methodology

Tasks Description

  • A set of prosocial tasks to assess generosity under varying conditions of personal cost.

  • Two main task types:

    • Costly Sharing Game (CSG): Choices between giving versus retaining resources.

    • Prosocial Game (PG): Choices with the opportunity to benefit both self and others without cost.

Experimental Setup

  • Conditions: Social (with recipient) vs. asocial (no recipient).

  • Standardized trials included:

    • Familiarization Tasks (FAM1, FAM2)

    • Two Test Trials (CSG, PG)

Age Parameter Analysis

  • Age centered to create a statistical model comparing likelihood of choosing prosocial outcomes:

    • Variables included centered age (CA) and squared centered age (CA²).

Statistical Modeling

  • Multilevel logistic regression used to analyze the outcomes based on participant choices.

  • Model selection via Deviance Information Criterion (DIC), identifying best-fit models to understand behaviors among populations.

Results Summary

  • Children differentiate between social and asocial conditions, with notable developmental trends in CSG behavior over age.

  • Over time, as costs of generous behaviors increase, variations arise between societies, leading to a population-specific adult behavior alignment.

Discussion

Developmental Implications

  • Non-monotonic patterns in development observed; young children may display a decrease in prosocial behavior as they approach middle childhood, contrary to previous studies suggesting an increase.

  • This pattern may stem from a growing preference for self-benefiting choices over altruistic ones in challenging situations.

  • Middle childhood represents a key period when cultural conformity begins influencing children’s prosocial behavior.

    • Observations signify an increasing understanding of social norms around age 6-7.

Conclusion and Future Directions

  • Findings indicate high variability across societies in prosocial development, primarily influenced by cultural norms and contexts of cooperation.

  • Future studies should focus on specific cultural influences affecting behavior and how these norms shape children's social preferences over time.