A systematic comparison of cooperation and coordination across behavioural, psychological, and neural scales

Cooperation and coordination are the two fundamental mechanisms for enhancing social welfare. However, the intrinsic differences between the dynamics of cooperation and coordination remain elusive, particularly from an interpretable perspective that bridges behavioural, psychological, and neural scales. Here, we compare and analyze cooperation and coordination within a unified framework by assigning participants to an adjustable public goods game for iterated real-time interactions. By integrating model-free behavioural patterns and psychological intentions, we show that individuals are driven by increased flexibility and are more susceptible to peer influence in decision-making under cooperation. While under coordination, it is easier to reach the group consensus, inspiring individuals to stick more closely to their existing behavioural patterns and the default social norms. Furthermore, although peer punishment can enhance reciprocal contributions in all scenarios, the detailed impact and the resultant adverse phenomena (anti-social punishment) in cooperation and coordination are different. Notably, behavioural motive differences are also reflected in the neural responses recorded via fNIRS, in which coordination is associated with activation of the rTPJ and more consistent inter-brain synchronization in the dmPFC, while there is a negative correlation between dmPFC-rTPJ connectivity and contributions under cooperation. In addition, rTPJ during the punishment phase is significantly activated compared with the investment phase. Our study systematically reveals the fundamental differences between cooperation and coordination at the multi-scale levels, which not only deepens the understanding of reciprocal behaviour in social groups, but also provides a foundation for designing targeted incentive mechanisms.