Can salient stimuli really be suppressed?
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Can salient stimuli really be suppressed? Seah Chang 1 & Howard E. Egeth 1 Accepted: 10 November 2020 # The Psychonomic Society, Inc. 2020
Abstract Although it is often assumed that a physically salient stimulus automatically captures attention even when it is irrelevant to a current task, the signal-suppression hypothesis proposes that observers can actively suppress a salient-but-irrelevant distractor. However, it is still unknown whether suppression alone (i.e., without target enhancement) is potent enough to override attentional capture by a salient singleton in an otherwise-homogeneous background. The current study addressed this issue. On search trials (70% of trials), participants searched for a shape target on trials that either did or did not contain an irrelevant color singleton. The effects of learning to suppress the color of the singleton were examined on interleaved probe trials (30% of trials). On these trials, participants searched for a probe target letter; those letters were presented on four ovals (one colored oval and three gray ovals). Each colored oval was a singleton that was one of three types: the color of the distractor on search trials, the color of the target on search trials, or a neutral color that had not appeared on search trials. Responses were faster for the probe target on a neutralcolored or target-colored item than on a gray-colored item; however, responses were slower for the probe target on a distractorcolored item than on a gray-colored item. The results demonstrate a powerful suppression mechanism overriding attentional capture by a singleton item. Keywords Attention . Attentional capture . Visual search
Introduction It is often assumed that physically salient items that differ from other stimuli in terms of a basic feature (i.e., feature singletons such as a red item among green items) automatically attract our visual attention. According to stimulus-driven theories, physically salient items automatically capture visual attention regardless of an observer’s current goals and intentions (e.g., Theeuwes, 1992). In a classic paradigm developed by Theeuwes (1992), when participants searched for a circle target among diamonds to report the orientation of a line inside the circle, responses to the target were slowed on trials on which a singleton color distractor appeared. This singletonpresence cost demonstrates attentional capture by the color singleton, slowing attentional allocation to the target. Such a bottom-up process is assumed to determine attentional priority (Itti & Koch, 2000). In some models it interacts with a top* Seah Chang [email protected] 1
Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
down process in which attention is guided by voluntary goals and intentions (Folk, Remington, & Johnston, 1992) as well as the history of attentional selection (Awh, Belopolsky, & Theeuwes, 2012; Theeuwes, 2018, 2019). Recently, the signal-suppression hypothesis has been proposed, suggesting that salie
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