Petitioner's Attire and Petition Signing by Peace Demonstrators: A Field Experiment1


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    Financial support for this research was obtained from the Rutgers University College Psychology Research Fund. The help of Marbeth Shay in conducting the experiment is gratefully acknowledged.

Requests for reprints should be sent to Dr. Peter Suedfeld, Department of Psychology, University College, Rutgers-The State University, New Brunswick, New Jersey 08903.


Two female experimenters, one dressed as a “hippie” and the other wearing “straight” dress, solicited signatures for an anti-war petition at the April 1971 Washington peace demonstration. Although the petition was identical in both conditions, and a large degree of attitudinal homogeneity in the subject population could be assumed, the hippie condition produced more signatures, more subjects who signed without looking at the petition, and attracted a larger number of unsolicited signatures. These differences were attributed to the effect of implied attitude (reference group) similarity between experimenters and subjects in the hippie and dissimilarity in the straight condition; in-group members were more effective than out-group members, despite experimenter-subject similarity in explicit attitudes under both conditions.