What is top-down about contingent capture?

In the present study, we explored the mechanisms involved in the contingent capture phenomenon, using a variant of the classic precuing paradigm of Folk, Remington, and Johnston (1992). Rather than keeping the target fixed over a whole block of trials (as has traditionally been done with contingent capture experiments), we encouraged participants to adopt a top-down set before each trial. If top-down attentional set determines which property captures attention, as is claimed by the contingent capture hypothesis, one would expect that only properties that match the top-down set would capture attention. We showed that even though participants knew what the target would be on the upcoming trial, both relevant and irrelevant properties captured attention (Experiment 1). An intertrial analysis (Experiments 1 and 2) showed that previous contingent capture findings may, to a large extent, be explained by intertrial priming. In addition, when participants were further forced into adopting the required top-down set (Experiments 3 and 4), irrelevant cues were suppressed, suggesting that top-down control might operate through disengagement of attention from the location of a property that does not match top-down goals. The present findings suggest that top-down control and intertrial priming make their own distinct contributions to the contingent capture phenomenon.