Finds strong positive main effects for teacher immediacy and strong negative effects for teacher misbehavior on all three dimensions of credibility (competence, trustworthiness, and caring/goodwill). Finds, however, that with low teacher immediacy, both "nonmisbehavior" and misbehavior produced perceptions of low credibility; whereas when teacher immediacy was high, teacher misbehavior significantly lowered perceived credibility. (SR)