Abstract
Interference by salient-but-irrelevant visual stimuli (distractors) in a visual pop-out-search task is well established. The present study examined the generalizability of this classic effect to auditory distractors. Participants’ task was to report whether the target (a 12º - tilted bar in a dense array of vertical bars, presented in half of the trials) was present or absent. In Experiment 1, 50% of the trials were accompanied by an auditory stimulus. Contrary to our expectations, results indicated a significant decrease in reaction times (RTs) and no significant change in accuracy when the auditory stimulus was present compared to when it was absent, indicating that the distractor might have acted as an alerting signal. However, an integrated performance measure that is relatively insensitive to speed-accuracy trade-offs – the Balance Integration Score (BIS; Liesefeld et al., 2015; Liesefeld & Janczyk, 2018), showed no effect of the auditory distractor on visual-search performance. Experiment 2 confirmed that the employed task design is sensitive to distractor interference by presenting a visual distractor (color singleton) instead of the auditory distractor; indeed, all dependent measures showed a significant decrease in visual-search performance. Experiment 3 eliminated the potential alerting signal by presenting an auditory stimulus in all trials, with an additional auditory stimulus in 50% of the trials as a distractor. Still, this auditory distractor produced no interference in terms of RTs, accuracies, or BIS. Oddball (i.e., relatively rare, deviating) stimuli are known to have a strong attention-grabbing power. Nevertheless, the absence of interference on visual search was replicated using auditory oddball stimuli presented in 25% of the trials either simultaneously (Experiment 4) or with a 300-ms head start in the race for attention (Experiment 5). Together, our results provide strong indication that task-irrelevant auditory stimuli have no impact on the performance of a visual pop-out search.