THE GAP EFFECT DURING VISUAL AND AUDITORY-STIMULATION USING MANUAL RESPONSES

Six experiments were conducted in naive human participants to examine any facilitation produced in manual reaction time (RT) by the interpos ition of a temporal gap between a warning signal and an imperative sig nal. Peripheral visual stimuli and monoaural auditory stimuli were use d as targets. Participants showed a facilitation of RTs to the targets for both auditory and visual stimuli in the five experiments in which RTs were the dependent variable. In addition, the gap effect increase d over successive blocks of trials, suggesting learning. RTs were faci litated only when the gap had predictive value and was salient. Using a variable temporal gap or a visual warning stimulus did not change th e facilitation in RTs. A further experiment demonstrated that the gap can be perceived by the participants. The dissociation between a learn ed and a non-learned component in the gap effect suggests that the tem poral gap induces two independent processes: warning and disengagement of attention. (C) 1998 Elsevier Science B.V.