"Support the strong" or "Help the weak?": The effects of social comparison and social distance on cooperative behavior in the dictator game.

Within an object-interdependent context, we conducted three experiments to investigate the influence of social comparisons on cooperative behavior, as well as to assess the mediating and moderating effects of related variables. In Experiment 1 (n = 207), we examined whether social comparisons impact cooperative behavior toward a comparator in a dictator game task. Here, we specifically focused on the mediating effects of evaluation of others' competence, along with three other potential mediators: self-competence evaluation, positive emotions, and negative emotions. Following the insights gained from Experiment 1, we proceeded to Experiments 2 (n = 279) and 3 (n = 298) to further explore whether social distance moderates the mediating effect of evaluation of others' competence. The results of all three experiments consistently indicated that upward (vs. non-) comparison facilitated cooperative behavior, whereas downward (vs. non-) comparison hindered it. Furthermore, our findings revealed that evaluation of others' competence served as a mediator between social comparison and cooperative behavior when the comparator (i.e., the cooperative partner) was perceived as being at a far-distance, whereas the mediating effect of evaluation of others' competence disappeared when social distance was close. These results reveal the pivotal role of evaluating others' competence and social distance in social interactions from the perspective of social comparison, which provides insights into how to promote cooperative behavior.