Costs or benefits of emotional conditioning on cognitive processing?

We report on two experiments using a transfer-of-control procedure in evalu ating costs or benefits of emotionally relevant stimuli on the processing o f a cognitive task. In differential conditioning the impact of Pavlovian co nditioning usually is examined by contrasting instrumental responses in the presence of an excitatory conditioned stimulus (CS +) and an inhibitory co nditioned stimulus (CS -). We expanded this comparison by introducing a neu tral third condition. This additional neutral condition served as a within subject control for evaluating whether the CS + increased responding and/or the CS - decreased responding. Both experiments yielded the same result: t he CS - slowed down cognitive processing while the CS + had no impact. Thus , the proposed transfer-of-control procedure may serve as a reliable and va lid research tool in the evaluation of motivation and emotion in humans. (C ) 2000 Elsevier Science B.V. All rights reserved.