The Effect of Top-down Attentional Control Setting on Attentional Capture

Abstract

The issue of how top-down modulation of Attentional Control Setting(ACS) occurs has been controversial. According to the simple filtering account, involuntary attentional captures do not occur when the cues do not match the top-down setting. The cues are filtered out under this condition, which results in a nonspatial filtering cost. However, according to the attentional disengagement account, all salient stimuli capture attention in a stimulus-driven manner, ACS modulates when the attention shifts away from an item which has captured attention. The key difference between the two accounts is that the former assumes irrelevant cues can't capture attention and that the latter believes irrelevant cues can be suppressed. It is believed that the studies supporting the former did not involve strong ACS and that the results were not fully explained by the top-down ACS. When participants could or were forced to establish strong ACSs, suppression effects of irrelevant cues would appear. The present study was designed to explore the mechanisms involved in the attentional capture phenomenon using a variant of the classic precuing paradigm. In Experiment 1, each participant looked for the same target color(red or green) throughout the entire experiment. At the beginning of each trial, a prompt announcing the color of the target would appear. It is believed that the use of prompt would make ACS not fluctuate during the experiment; therefore, the participants would maintain a strong ACS level. In Experiment 2, every participant looked for a random sequence of target colors(red and green) which changed unpredictably on a trial-by-trial basis. Under such circumstance, the participants had to process the prompt with the target color in each trial so that they could find the relevant color in the target and respond correctly. The results demonstrated that(1) in both experiments, it was found that matched cues resulted in pronounced attention capturing effect, that irrelevant cues were suppressed and that the suppression effects were significantly smaller than the capture effects,(2) the capture effects of matched cues and the suppression effects of irrelevant cues in Experiment 2 were significantly larger than those in Experiment 1,(3) there was no significant difference between the suppression effects induced by irrelevant distractor-color cues and those induced by irrelevant neutral-color cues, It was concluded that(1) ACS operated through disengagement of attention from the location of a property that did not match ACS, which was followed by suppression of processing at that location, which supported the attentional disengagement account,(2) the capture of matched cues and the suppression of irrelevant cues used the same processing system; suppression of irrelevant features occurred as a by-product of facilitative ACSs, both of which were indicators for attentional capture.