College students and suburban residents completed questionnaires designed to examine the tendency of scientific explanations of undesirable behaviors to mitigate perceived culpability. In vignettes relating behaviors to an explanatory antecedent, we manipulated the uniformity of the behavior given the antecedent, the responsiveness of the behavior to deterrence, and the explanatory antecedent-type offered- physiological (e.g., a chemical imbalance) or experiential (e.g., abusive parents). Physiological explanations had a greater tendency to exonerate actors than did experiential explanations. The effects of uniformity and deterrence (...) were smaller, and the latter had a significant effect on judgment only when physiological rather than experiential antecedents were specified. Physiologically explained behavior was more likely to be characterized as "automatic", and willpower and character were less likely to be cited as relevant to the behavior. Physiological explanations of undesirable behavior may mitigate blame by inviting nonteleological causal attributions. Keywords: person perception, volition, moral attribution, responsibility. (shrink)