A neurocognitive mechanism for increased cooperation during group formation

Area of Science:

• Neuroscience
• Social Psychology
• Behavioral Economics

Background:

• Cooperation is essential for social cohesion and group success.
• Understanding the dynamics of cooperation in varying group sizes is crucial.
• Previous research has not fully elucidated the cognitive and neural mechanisms underlying group size effects on cooperation.

Purpose of the Study:

• To investigate how changes in group size influence cooperative behavior.
• To identify the cognitive and neural underpinnings of cooperation modulation by group size.
• To explore the interplay between individual tendencies and strategic decision-making in dynamic group settings.

Main Methods:

• A dynamic, network-based prisoner's dilemma experiment was conducted with 83 participants.
• Functional magnetic resonance imaging (fMRI) was used to capture neural activity during the experiment.
• Computational modeling was employed to analyze behavioral data and fMRI findings.

Main Results:

• Cooperation increased with larger group sizes.
• Group size itself did not directly increase cooperation; rather, it modulated the interaction between prosocial tendencies and reciprocal strategies.
• Memory confidence, influenced by forgetting and recall uncertainty, played a key role, shifting the balance towards prosociality in larger groups.
• Neural correlates of memory confidence (fusiform gyrus, precuneus) and its integration with prosocial tendencies (left DLPFC, dACC) were identified.

Conclusions:

• Emergent cooperation in dynamic groups is driven by the interaction between individual prosocial preferences and memory confidence during reciprocal interactions.
• Recall uncertainty, or forgetting, influences this interaction, favoring prosociality in larger groups.
• Neural mechanisms involving memory encoding and integration with social decision-making underpin these group size effects on cooperation.