Neural Implementation of computational mechanisms underlying the continuous trade-off between cooperation and competition

Social interactions evolve continuously. Sometimes we cooperate, sometimeswe compete, while at other times we strategically position ourselves somewherein between to account for the ever-changing social contexts around us.Research on social interactions often focuses on a binary dichotomy betweencompetition and cooperation, ignoring people’s evolving shifts along a continuum.Here, we develop an economic game – the Space Dilemma – wheretwo players change their degree of cooperativeness over time in cooperativeand competitive contexts. Using computationalmodelling we showhowsocialcontexts bias choices and characterise how inferences about others’ intentionsmodulate cooperativeness. Consistent with the modelling predictions, brainregions previously linked to social cognition, including the temporo-parietaljunction, dorso-medial prefrontal cortex and the anterior cingulate gyrus,encode social prediction errors and context-dependent signals, correlatingwith shifts along a cooperation-competition continuum. These results providea comprehensive account of the computational and neural mechanismsunderlying the continuous trade-off between cooperation and competition.