公共財ゲームにおける意思決定と生理的反応

心拍反応による検討

抄録

A social dilemma has been defined as a situation in which (a) each group member receives a higher payoff for defecting than for cooperative behaviors, and (b) all group members receive a lower payoff if they all defect than if they all cooperate (Dawes, 1980). The free-rider problem is associated with this social dilemma. The public goods game (PGG) is a decision-making task simulating the above social dilemma, and a number of previous studies have indicated that introducing punishment increases cooperation in the PGG. Although many studies have indicated that physiological responses affected by participants' behaviors when performing punishment-related tasks, this association has not been investigated to date in relation to PGG. Therefore, we investigated physiological responses in the PGG to elucidate the association between physiological responses and choices in the PGG. Participants performed both an ordinary PGG and a PGG that included probabilistic punishment. Heart rate (HR) responses were compared when participants contributed and did not contribute in the two types of PGGs. Results indicated that when others' choices were presented in the ordinary PGG, peak HR acceleration was higher after participants choose a non-cooperative behavior than a cooperative behavior, whereas when others' choices were presented in PGG with punishment, HR decelerated after participants choose a non-cooperative behavior than a cooperative behavior. These results suggest that cooperative behaviors in PGG with punishment are associated with punishment given to others, whereas cooperative behaviors in the PGG without punishment are associated with larger rewards without costs. These findings extend our understanding of the relationship between cooperative behaviors and physiological responses associated with social dilemmas.