ABSTRACT
A uniquely coloured singleton among other uniformly coloured stimuli can function as a powerful attractor of attention. However, top-down attentional mechanisms are also powerful, and there are circumstances in which they can suppress irrelevant distractors. The current study tested whether an endogenous spatial cue indicating the location of a salient colour singleton distractor can eliminate involuntary attentional allocation to such a stimulus. When an arrow cue indicated a to-be-ignored location that would never contain a target but would contain a colour singleton distractor, a significant singleton capture effect was eliminated on ignore trials regardless of the consistency of the singleton colour in Experiments 1 and 2. In Experiment 3, a consistent colour singleton was used without a spatial cue. Participants were not able to suppress singleton distractors in the absence of a cue. However, in Experiments 1 & 2, the status of a letter inscribed in the singleton (i.e., whether it is compatible or incompatible with the target of the search) did affect reaction time on ignore trials. If the compatibility effect indicates a shift of attention to the singleton, the data may mean that, with a spatial cue, participants inhibit a cued location by first selecting the location and then rapidly disengaging from it.
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Acknowledgement
We thank Jason Fischer for valuable suggestions and helpful comments on an earlier draft of this paper.
Disclosure statement
No potential conflict of interest was reported by the authors.
Notes
1 In the pilot experiment, the same experimental design with four stimuli was tested to determine the optimal design for the competition between powerful top-down cue and powerful singleton distractor with high-salience signal. The main effect of cue type was significant, F(1, 35) = 14.56, p = .001, = .294, demonstrating search was faster on ignore trials than on neutral trials. The main effect of compatibility was also significant, F(1, 35) = 104.07, p < .001, = .748, indicating that search was faster on compatible trials than on incompatible trials. Compatibility effects did not interact with cue type, p = .9, demonstrating that a stimulus in the cued location was processed on both trials. Importantly, the effect of singleton was not significant, p > .4. The absence of singleton effects seems to be because the singleton distractor cannot pop out from the other white letters because of low-salience signal in the four-item display. Therefore, we used eight-item displays in the main experiments reported in this paper. The interaction between cue type and singleton was not significant, p > .2. The interactions among cue type, singleton, and compatibility reached significance, F(1, 35) = 4.54, p < .05, = .115.