Abstract:
Background. Cooperation is an adaptive human behaviour that is fundamental to navigating our social worlds. The critical role that cooperation plays in human societies has fuelled the view that cooperation has a biological basis, however, little research has addressed a genetic contribution to cooperation in the early stages of human development. The current study represents a first step towards addressing this by exploring the extent to which variations in five candidate genes (DRD4, MOAOA, COMT, OXTR, CHRNA4) shape 22-month-old infants’ cooperative behaviour as a function of their temperament. Methods. 203 12-month-old infants gave DNA samples, at 22-months-old they participated in two novel problem-solving tasks. Infants’ behaviour during these tasks and a corresponding interruption period was coded to attain measures of their cooperative ability, engagement, understanding and social behaviour. Results. Results showed no relationship between temperament and measures of cooperation except effortful control which was positively correlated with the proportion of time infants spent attempting to complete the task on their own. Further analysis revealed that variability in the CHRNA4 gene was associated with how infants apply their attention to a cooperative task and variability in both the CHRNA4 and OXTR genes were associated with infants’ understanding of the social aspect of cooperation, as seen by the proportion of time infants attempted to re-engage the experimenter during the interruption period. No significant findings were seen for the DRD4, MAOA and COMT genes. Conclusions. The current study adds to the handful of studies looking at the biological basis of cooperation and provides further evidence for small variations in genetic makeup influencing behaviour. Further research is needed to determine the robustness of these findings across development, but the current study helps us to better understand the biology of cooperation and begin to explore the mechanisms for how we navigate our social worlds.