Two studies were conducted to test the predictions derived from the behavioral activation system and behavioral inhibition system theory of personality that trait anxiety is positively related to the speed of acquisition of punishment expectancies and impulsivity is positively related to the speed of acquisition of reward expectancies. Both studies used a standard approach-avoidance discrimination task with self-report measures of expectancies. Both studies found support for the hypothesized relation between trait and acquisition of punishment expectancies but not for the hypothesized relation between impulsivity and acquisition of reward expectancies. Study 2 suggested that the relation between trait anxiety and punishment expectancy is affected by the type of incentive and the type of trait anxiety measure used. The results suggest that highly trait anxious individuals are more susceptible to developing new sources of anxiety than others.