The revised Reinforcement Sensitivity Theory (rRST) of personality (Gray & McNaughton, 2000) maintains that trait individual differences in the operation of defensive systems relate to facets of human personality, most notably anxiety and fear. We investigated this theory in 2 separate studies (total N=270) using a threat scenario research strategy (Blanchard, Hynd, Minke, Minemoto, & Blanchard, 2001). Consistent with rRST, results showed that individuals with high fear questionnaire scores tended to select defensive responses entailing orientation away from threat (e.g., run away) and that fear-prone individuals also tended to perceive threats as magnified. The extent of this threat magnification mediated the positive association observed between fear and orientation away from threat. Overall, results suggest that interindividual variance in defensive reactions is associated with a variety of existing personality constructs but that further research is required to determine the precise relationship between personality and defensive reactions.