The More, the Merrier

Teamwork has long been crucial for human survival, but scientists traditionally believed that cooperation declines as group size grows.

New research, however, challenges those beliefs, showing that larger groups can enhance collaboration.

Researchers at the RIKEN Center for Brain Science made 83 study participants play the prisoner’s dilemma game – a scenario in which players have to choose to either cooperate for mutual benefit or act in self-interest without knowing others’ choices.

In the experiment, groups ranged from two to six participants, and players were allowed to leave a group they didn’t like or remove uncooperative members.

Unexpectedly, people in larger groups were more likely to cooperate, making 57 percent of all decisions together.

However, by monitoring participants’ brain activity with functional magnetic resonance imaging throughout the game, researchers found that group size itself was not the factor directly encouraging cooperation. Rather, it impacted the way people remembered social interactions and made future decisions.

Brain scans showed that specific brain regions processed memories of past social interactions while others connected the memories to feelings of reward. The prefrontal cortex was found responsible for weighing previous memories against personal tendencies and determining whether or not a participant should cooperate with someone who may have previously betrayed them.

When participants struggled to remember previous interactions, their prefrontal cortex naturally encouraged cooperation over caution, leading to prosocial behaviors – namely, acting to benefit others following their general inclinations to trust and collaborate.

This behavior is believed to pave the way for smoother group dynamics and the maintenance of harmony.

Finding that people have evolved to cooperate effectively in large societies, even outside of stable, well-known relationships, “could help improve teamwork in schools, workplaces, and online environments,” said lead study author Rei Akaishi.