Abstract
The issue whether attentional capture is determined by top-down factors or it can be purely stimulus-driven remains unsolved. Proponents of the contingent capture hypothesis argue that only the distractor that matches the target characteristics can capture attention, whereas those of the stimulus-driven capture hypothesis argue that attentional capture occurs regardless of distracter-target contingency. We aimed at solving this discrepancy by finding boundary conditions of the two contrast hypotheses and further proposed an interactive model to explain the results. We used a spatial cueing paradigm, in which a color target was followed by an uninformative cue that either matched (a color cue) or did not match (an onset cue) the target to test whether and how the cue captures attention. We added a no-cue condition beforehand to make the very first with-cue trial unexpected to the participants, and analyzed the response to the first with-cue trial to contrast it with the average data. Results showed that the onset cue captured attention to its location when it appeared unexpectedly, but this effect disappeared over repeated trials. In contrast, the color cue did not capture attention when it appeared unexpectedly but did so over repeated trials. We thus demonstrate that, on one hand, the contingent capture hypothesis is supported under the condition that when the same cue is presented repeatedly, top-down modulation determinates the capture effect. On the other hand, the stimulus-driven hypothesis holds true under the condition that when the cue is presented for the first time, the onset cue captures attention even when it does not match with the target defining feature. The proposed interactive model in which stimulus-driven orienting exists at early time course but is later modulated by top-down controls can adequately explain the results by distinguishing attentional capture through stimulus-driven orienting from that through top-down modulation.
This study is supported by 98-2410-H-002-023-MY3 and 96-2413-H-002-009-MY3.