Novel tests of capture by irrelevant abrupt onsets: No evidence for a mediating role of search task difficulty during color search.

According to the attentional dwelling hypothesis, task-irrelevant abrupt-onset cues capture attention in a stimulus-driven way by eliciting spatial shifts and further dwelling at cue position until target onset. Consequently, search can be facilitated for targets at cued locations relative to uncued locations. Critically, effects of stimulus-driven capture can go undetected in mean reaction times and error rates when search is too easy. In contrast, according to the priority accumulation framework (PAF), cueing effects for task-irrelevant cues differ from cueing effects by task-relevant cues. Most critically, cueing effects by irrelevant cues do not necessarily index spatial shifts and more dwelling but rather retrieval of cueing information. We used both behavioral measures (i.e., cueing effects and distractor compatibility effects) and event-related potentials on direct visual orienting activity elicited by the cue (Experiment 2) as well as consequences on target processing (Experiment 1) to investigate whether task-irrelevant abrupt onsets elicited attention shifts and led to further dwelling. We found behavioral support for attentional effects of task-irrelevant cues, surprisingly, however, only when search displays remained on-screen until response. We found no support for the attentional dwelling hypothesis or for PAF in the size of cueing effects as a function of search difficulty. Critically, lateralized ERPs revealed that salience of abrupt onsets per se is not sufficient to elicit spatial shifts during color search. Finally, neurophysiological evidence demonstrates that choices toward the implementation of experimental protocols can dramatically alter behavioral results on attentional effects of salient, but task-irrelevant abrupt onsets and conclusions drawn from them.