"The investigation reported in this study concerns the partial repetition of a study by Doob and Sears in which the arbitrary character of the situations was unintentionally an unacknowledged factor. Situations (the arbitrary set) were drawn up which paralleled those used by Doob and Sears. Modifications of the arbitrary set in the direction of non-arbitrariness was found to reduce considerably the number of aggressive responses which were elicited. The result was interpreted to imply that the arbitrary character of a frustrating situation should be part of a theory that attempts to explain the relationship between frustration and aggression." (PsycINFO Database Record (c) 2006 APA, all rights reserved)