Towards a resolution of the attentional-capture debate.

The relative contributions of stimulus-driven and goal-directed control of attention have been extensively studied by investigating which irrelevant stimuli capture attention. Although much of this research has focused on color-singleton distractors, the circumstances under which these capture attention remain controversial. In search for a target with a unique known color (known-singleton search), whether singletons in an irrelevant color can be successfully ignored is a hotly debated issue. In search for a target that is not a singleton (feature search), no capture by irrelevant-color singletons is typically observed, but a reverse cueing effect was occasionally reported in the spatial-cueing paradigm. In 3 experiments, we resolve these controversies, by showing that the net spatial effect observed in the spatial-cueing paradigm reflects the sum of 3 separate effects. (a) A same-location benefit, which is determined by the match between the cue and the target colors and indexes contingent attentional capture. (b) A same-location cost, which is also determined by the match between the cue and the target colors, but occurs after selection and indexes processes related to visual working memory; and (c) task-dependent capture by singletons that occurs only when the target is consistently a singleton. Crucially, we show that the same-location cost is strongly determined by cue exposure duration, which explains previous failures to isolate it. The implications of these findings for the attentional capture debate are discussed.