Top-down control settings and the attentional blink: Evidence for nonspatial contingent capture

Previous studies have shown that spatial attention can be "captured'' by irrelevant events, but only if the eliciting stimulus matches top-down attentional control settings. Here we explore whether similar principles hold for nonspatial attentional selection. Subjects searched for a coloured target letter embedded in an RSVP stream of letters inside a box centred on fixation. On critical trials, a distractor, consisting of a brief change in the colour of the box, occurred at various temporal lags prior to the target. In Experiment 1, the distractor produced a decrement in target detection, but only when it matched the target colour. Experiments 2 and 3 provide evidence that this effect does not reflect masking or the dispersion of spatial attention. The results establish that (1) nonspatial selection is subject to "capture'', (2) such capture is contingent on top-down attentional control settings, and (3) control settings for nonspatial capture can vary in specificity.