To examine the effects of learned helplessness on tasks used to assess the aftereffects of stress, 42 internal and external undergraduates (selected by scores on a brief form of Rotter's Internal–External Locus of Control Scale) were pretreated with contingent or noncontingent nonnoxious reinforcement using a yoking procedure to control for amount of trials and reinforcement. Both internal and external noncontingent Ss performed more poorly on subsequent tasks requiring a problem-solving strategy. However, only externals showed helplessness effects on non-problem-solving tasks.