Blink reflexes were studied in 40 subjects at rest and during the performance of a task. The early reflex (R1) showed an increase of amplitude of action potential during the task, the late reflex (R2) did not. The latency of R1 did not change within the 45 minutes test period; R2 showed an increase of latency during task. R1 showed a systematic decrease in amplitude within rest and task periods, presumably because of habituation. R2 amplitudes decreased throughout the whole experiment, independent of task or rest.