The belief theory of prejudice introduced by M. Rokeach stated that racial prejudice is the result of the anticipation of belief differences. The unidirectional causal relationship implied is criticized as oversimplified. Research supporting the belief theory is examined, with conceptual and experimental deficiencies noted. A new formulation is proposed which emphasizes mutual causality between racial prejudice and anticipated belief differences. Two studies supporting that view are presented in which belief communications were presented as tape-recorded interviews or speeches, with the race and social class of the communicator first having been manipulated. The interrelationships between communicator's race, specific communication topic, and subject's prejudice level on the dimensions of felt similarity of the subject to the communicator are seen as supporting the mutual causation formulation.The belief theory of prejudice suggests that prejudice results from an aversion toward individuals who hold beliefs which are incongruent with one's own. It was postulated that the aversion toward incompatible beliefs was due to universal needs for consensual validation (Rokeach, Smith, & Evans, 1960) and/or the desire for the reinforcement provided by belief agreement (Byrne & Wong, 1962). Furthermore, belief theory proponents have suggested that without anticipations about belief differences, no prejudice would exist.