Parochial cooperation in nested intergroup dilemmas is reduced when it harms out-groups

Area of Science:

• Social Psychology
• Behavioral Economics
• Game Theory

Background:

• Humans exhibit parochial cooperation, benefiting their in-group at personal cost.
• This behavior can escalate intergroup conflict by harming out-groups.

Purpose of the Study:

• To investigate choices between universal and parochial cooperation.
• To test theories of group selection, social identity, and bounded generalized reciprocity.
• To understand the conditions under which parochial cooperation occurs.

Main Methods:

• Introduction of a novel game paradigm allowing universal and parochial cooperation choices.
• Three experiments testing hypotheses across different conditions.
• Analysis of cooperation choices in relation to group benefit and harm.

Main Results:

• Individuals consistently favored parochial cooperation over universal cooperation.
• No evidence found for maximizing in-group/out-group differences, challenging group selection and social identity theories.
• Prosocial individuals engaged in parochial cooperation only when it did not harm out-groups.
• Individualists displayed parochialism regardless of harm to out-groups.

Conclusions:

• Parochial cooperation is a prevalent behavior, influenced by individual value orientations.
• Bounded generalized reciprocity theory better explains the observed patterns than group selection or social identity theory.
• The findings highlight the nuanced nature of cooperation and intergroup behavior.