Inhibition of helping behavior by a similar or dissimilar nonreactive fellow bystander

60 male undergraduates observed a female E suffering apparent physical distress under 1 of 3 conditions: (a) alone, (b) in the presence of a nonreactive confederate supposedly similar to themselves in attitudes, or (c) in the presence of a dissimilar nonreactive confederate. On the basis of L. A. Festinger's social comparison theory, it was predicted that Ss exposed to the similar nonreactive fellow bystander would be less likely to intervene to help the "lady in distress" than would be the case when Ss were exposed to a dissimilar nonreactive other. Results strongly support this prediction. Only 5% of the Ss in the similar fellow bystander condition intervened, compared with an intervention rate of 35% in the dissimilar other condition. In the alone condition, 65% of the Ss intervened to help the victim. Ss in the dissimilar other condition who failed to intervene showed a significant increase in both emitted and expected attraction in relation to the nonreactive fellow bystander.