Attentional Alertness Does Not Facilitate Rejecting Distractors

Increased phasic alertness is a useful mechanism that temporarily improves many aspects of behavior, including visual capacities. The present study examined the effect of increased alertness on the effectiveness of later rejecting distractors in a simple color change-detection task. In two experiments, participants performed a color short-term memory task with three conditions: no-distractors, distractors, and distractors preceded by an auditory warning cue. The results from Experiment 1 showed no benefit in rejecting distracting information after hearing a warning cue before the presentation of visual distractors. In Experiment 2, the warning cues expedited the detection of dots appearing infrequently and unexpectedly after the distractors, confirming that the cues effectively increased alertness. Importantly, however, memory performance was, once again, not improved following the cues, suggesting that increased alertness has a limited impact on filtering out irrelevant, distracting information. This finding further indicates that allocating attention to upcoming distractors is not part of an effective process for rejecting distractors, but rather a mandatory process when expecting any stimulus to appear.