Alerting and Orienting: Interaction or independence?

Four experiments assessed the relation betweenalerting and orienting under peripherally andcentrally cued conditions separately, in both detectionand discrimination tasks. Alerting was manipulatedby presenting a warning tone before or simultaneously with visual cue on 25% of the trials.Results indicated that alerting and orienting interactunder central cuing conditions. As respect todetection, the warning selectively facilitated RTs onValid and Neutral, but not on Invalid trials. Whena discrimination was required, the warning seems toanticipate the processing of the cue. Results confirman interaction between alerting and orienting, onlywhen an endogenous attentional shift is required.