Data is brought to bear on the social influence hypothesis, according to which the behavior of one bystander influences other bystanders by providing information leading to a definition of the situation. The study placed a subject in an emergency situation in which one of 3 confederates served as a model: (1) male peer; (2) female peer; or (3) high status male. In the control condition there was no model. When a male model failed to offer assistance there was a significant decrease in helping on the part of the subjects. In all other cases the rate of helping was high. The results indicate that the greater influence of the male model, as compared with the female model, was due to his greater ability to provide information which could be accepted as a valid definition of the emergency situation. The authors interpret the results as supporting the social influence hypothesis of Latane and Darley (1968). (Author/TL)