Investing in commitment: Persistence in a joint action is enhanced by the perception of a partner's effort.

Can the perception that one's partner is investing effort generate a sense of commitment to a joint action? To test this, we developed a 2-player version of the classic snake game which became increasingly boring over the course of each round. This enabled us to operationalize commitment in terms of how long participants persisted before pressing a 'finish' button to conclude each round. Our results from three experiments reveal that participants persisted longer when they perceived what they believed to be cues of their partner's effortful contribution (Experiment 1). Crucially, this effect was not observed when they knew their partner to be an algorithm (Experiment 2), nor when it was their own effort that had been invested (Experiment 3). These results support the hypothesis that the perception of a partner's effort elicits a sense of commitment, leading to increased persistence in the face of a temptation to disengage.