VARIATION OF THE INTERTRIAL INTERVAL IN HUMAN CLASSICAL-CONDITIONING

The effect of using a short intertrial interval (ITI) in eyeblink clas sical conditioning in humans was examined. The performance of normal y oung adults in 750-msec delay conditioning was compared at ITIs of 5, 10, and 30 sec. All groups successfully acquired the task. Performance of each ITI group was similar for pseudoconditioning, conditioning, a nd extinction trials. Use of shorter ITIs during eyeblink conditioning should reduce test time and possible subject boredom or inattention, thus making the eye-blink conditioning task more useful as part of a n europsychological test battery for evaluating brain damage and drug ef fectiveness. Shorter ITIs would also allow eyeblink classical conditio ning to be used in concert with other technologies, such as PET scanni ng, to assess functional activity of the brain during learning.