Beliefs and Cooperation (original) (raw)

Is collaboration the fast choice for humans? Past studies proposed that cooperation is a behavioural default, based on Response Times (RT) findings. Here we contend that the individual's reckoning of the immediate social environment shapes her predisposition to cooperate and, hence, response latencies. In a social dilemma game, we manipulate the beliefs about the partner's intentions to cooperate and show that they act as a switch that determines cooperation and defection RTs; when the partner's intention to cooperate is perceived as high, cooperation choices are speeded up, while defection is slowed down. Importantly, this social context effect holds across varying expected payoffs, indicating that it modulates behaviour regardless of choices' similarity in monetary terms. Moreover, this pattern is moderated by individual variability in social preferences: Among conditional cooperators, high cooperation beliefs speed up cooperation responses and slow down defection. Among free-riders, defection is always faster and more likely than cooperation, while high cooperation beliefs slow down all decisions. These results shed new light on the conflict of choices account of response latencies, as well as on the intuitive cooperation hypothesis, and can help to correctly interpret and reconcile previous, apparently contradictory results, by considering the role of context in social dilemmas. Human cooperation –sacrificing individual resources to achieve higher collective welfare– poses an evolutionary puzzle in both social and natural sciences: even if selfishness leads to higher evolutionary fitness, cooperation is nevertheless widespread among humans 1–3. Understanding the cognitive processes underlying human cooperation is essential for solving this puzzle. Researchers have therefore studied the Response Times (RT) of choices in social dilemma decisions (i.e. situations where private and social interests are in conflict) to address whether cooperation is the fast, unconflicted choice among humans (please note that quick choice speed has been taken to indicate the default or intuitive behaviour 4–7 , although this interpretation is not always conclusive). However, this method has produced mixed results; while several studies indeed found that individuals make cooperation choices significantly faster than selfish choices 4–8 , others reported the opposite pattern 9–11. Similar findings were found employing different methodologies such as time pressure 7,12–14 , ego depletion methods 15–18 as well as structural and functional neural correlates 19–22 ; while most of the studies find that cooperation is the default choice among humans, other studies either fail to replicate or even find results in the opposite direction (for neuroeco-nomics see 23,24 ; for time pressure 25–27 ; for ego depletion 28). Taken together, the literature leaves little room for doubt that, at least in some occasions, cooperation is the choice favoured by individuals, or at least the one they take faster. The key question is then: Under which circumstances cooperation emerges as the unconflicted, fast choice? It has been suggested that RTs are driven by the overall attractiveness of the available choices: the more similar the expected payoffs of the available options are, the higher the conflict of the choice and ultimately the slower the RTs, since the choice is harder to make 29–32. However, attractiveness is measured in units of utility, and therefore it may arise from a variety of factors including stimulus related factors (i.e. monetary returns of choices) 29 , individuals' social preferences 21,29 , or evaluation of partners' past behaviour 33,34. As such, the conflict of choices account can explain some fast behaviours without Published: xx xx xxxx OPEN