Human-robot cooperation in economic games: People show strong reciprocity but conditional prosociality toward robots

摘要

Understanding the social dynamics in human-robot cooperation stands to broaden our understanding of human behaviour in general, as well as to improve the design of robots designated for certain social tasks. This study investigated human cooperative behaviours in the context of prisoner’s dilemma (PD) games and the extent to which people’s willingness to cooperate with a robot varies according to incentives provided by the game context. We manipulated the payoff matrices of human-robot PD games and predicted that people would cooperate more often in the situation where cooperating with the robot was a relatively more rewarding option. Although the pre-registered mixed effect logistic regression model showed no significant effect of incentive structure on human decisions in the iterated PD games overall, further exploratory analyses revealed that in early game rounds, participants made significantly more cooperative decisions when the game structure provided more incentives for cooperation. However, subsequent game decisions were dominantly driven by other two factors. The first was the robot’s previous game choices, where participants played a tit-for-tat strategy against the robot even though its decisions were random. Second, presentation of real-time game scores significantly impacted people’s cooperative tendencies. Participants only showed prosocial tendencies toward the robot when they had achieved high scores themselves. Our findings on the initial effects of incentive structure, robust reciprocity, and conditional prosociality in human-robot cooperation highlight ways in which we might expect social behaviour toward robots to differ from social behaviour toward humans, and help to establish the foundations necessary to support successful social collaboration with robots.