Others' participation rate influences an individual's charitable behavior: Others' similarity as a moderator

We proposed that a moderator, others' similarity, would determine the impact of high participation rates of others on an individual's charitable behavior, and aimed to show that this moderator would work through the diffusion of responsibility motive. Participants ( N = 152 undergraduate students) completed measures of charitable behavior and diffusion of responsibility, after being assigned to 1 of 2 conditions where a set percentage of other students (manipulated as either similar undergraduate students or dissimilar graduate students) were stated to have already donated to a charitable campaign (high contribution condition = 70% participation, low contribution condition = 30% participation). Our results showed that the high participation rate of others increased an individual's charitable behavior when the others in question were similar to that individual, but not when the others were dissimilar. In addition, the high rate of participation by others increased the diffusion of responsibility motive when the others in question were dissimilar to that individual, leading to a negative effect on that individual's charitable behavior.