The question whether attentional capture by salient but taskirrelevant
visual stimuli is triggered in a bottom–up fashion or
depends on top–down task settings is still unresolved. Strong support
for bottom–up capture was obtained in the additional singleton
task, in which search arrays were visible until response onset.
Equally strong evidence for top–down control of attentional capture
was obtained in spatial cueing experiments in which display
durations were very brief. To demonstrate the critical role of temporal
task demands on salience-driven attentional capture, we
measured ERP indicators of capture by task-irrelevant color singletons
in search arrays that could also contain a shape target. In
Experiment 1, all displays were visible until response onset. In
Experiment 2, display duration was limited to 200 msec. With long
display durations, color singleton distractors elicited an N2pc component
that was followed by a late Pd component, suggesting that
they triggered attentional capture, which was later replaced by
location-specific inhibition. When search arrays were visible for
only 200 msec, the distractor-elicited N2pc was eliminated and
was replaced by a Pd component in the same time range, indicative
of rapid suppression of capture. Results show that attentional
capture by salient distractors can be inhibited for short-duration
search displays, in which it would interfere with target processing.
They demonstrate that salience-driven capture is not a purely
bottom–up phenomenon but is subject to top–down control.