Evidence for a cooperative phenotype in humans is reported online this week in Nature Communications. Phenotypes are characteristics produced by the interaction of genes and the environment.
Cooperation is fundamental to the success of social species, yet cooperation requires individuals to make sacrifices to benefit others. Understanding how and when humans cooperate, as well as why evolution and strategic reasoning give rise to cooperation, is a major challenge for researchers across the natural and social sciences.
David Rand and colleagues generated a large body of experimental data supporting the existence of a cooperative phenotype by collecting thousands of game decisions from more than 1,400 individuals. They used cooperation games, norm-enforcing punishment games and competition games to investigate whether decisions to cooperate correlate across different scenarios. The authors also investigated whether game play reflects underlying moral values, using the World Values Survey, as well as investigating actual helping behaviour outside of games by informing participants that the experiment was over and then asking them to help experimenters by giving feedback.
They find that a person’s decisions in different cooperation games are correlated. They also find that game decisions are correlated with both self-report and real-effort measures of cooperation in non-game contexts. Equally strong correlations were shown to exist between cooperative decisions made an average of 124 days apart, indicating that cooperation is stable over time. Finally, they show that cooperation is not correlated with norm-enforcing punishment or non-competitiveness, showing little experimental evidence in support of a situation-dependent penchant for cooperation. Taken together, these experiments provide an extensive assessment of the generality of human social preferences, providing evidence for a ‘cooperative phenotype’.