The hypothesis that salient distractors in visual search are actively suppressed is supported by the fact that these objects elicit P_D components believed to be associated with inhibition. This account was challenged by researchers who found that a P_D to lateral color singleton distractors was followed by a contralateral negativity, which they interpreted as an N2pc indicative of attentional capture. As this would be at odds with successful distractor suppression, they proposed an alternative lateral-first serial scanning hypothesis, which assumes that the P_D might actually be an N2pc elicited when a lateral context item is selected. We tested this hypothesis by measuring lateralized ERP components to search displays with two lateral and two vertical midline items, including a color singleton and a shape-defined target. Color singletons triggered P_D components not only in blocks where attention was unfocused because target location was unpredictable, but critically also in blocks where targets only appeared on the midline and participants had no reason to attend to lateral items. This is inconsistent with the serial scanning hypothesis and supports the idea that the P_D reflects signal suppression. P_D components to singleton distractors were followed by a contralateral negativity, which we interpreted as a second P_D elicited by nonsalient distractors on the opposite side. Our sequential inhibition account reconciles conflicting results of recent studies and emphasizes the role of inhibitory processes during attentional target selection in visual search.

中文翻译：

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视觉搜索中的 PD 成分和干扰物抑制：信号抑制假说的新证据

视觉搜索中的显着干扰物被积极抑制的假设得到了以下事实的支持：这些物体引发了被认为与抑制相关的P _D成分。这一说法受到研究人员的挑战，他们发现对侧颜色单一干扰物的 P _D之后是对侧的消极性，他们将其解释为 N2pc 指示注意力捕获。由于这与成功的干扰抑制不符，他们提出了另一种横向优先连续扫描假设，假设 P _D实际上可能是在选择横向上下文项目时引发的 N2pc。我们通过测量横向 ERP 组件来测试这个假设，以搜索具有两个横向和两个垂直中线项目的显示，包括一个颜色单例和一个形状定义的目标。颜色单例不仅在由于目标位置不可预测而导致注意力不集中的区块中触发 P _D分量，而且在目标仅出现在中线且参与者没有理由关注横向项目的区块中也很重要。这与串行扫描假设不一致，支持 P _D反映信号抑制的观点。PD _{_}单个干扰项的组成部分之后是对侧的消极情绪，我们将其解释为由对侧的非显着干扰项引起的第二个 P _D。我们的顺序抑制帐户调和了最近研究的相互矛盾的结果，并强调了抑制过程在视觉搜索中注意目标选择过程中的作用。