Group inhibition of bystander intervention in emergencies.

Male undergraduates found themselves in a smoke-filling room either alone, with 2 nonreacting others, or in groups of 3. As predicted, Ss were less likely to report the smoke when in the presence of passive others (10%) or in groups of 3 (38% of groups) than when alone (75%). This result seemed to have been mediated by the way 5s interpreted the ambiguous situation; seeing other people remain passive led Ss to decide the smoke was not dangerous.