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There has been a long-lasting debate about whether salient stimuli, such as uniquely colored objects, have the ability to automatically distract us. To resolve this debate, it has been suggested that salient stimuli do attract attention but that they can be suppressed to prevent distraction. Some research supporting this viewpoint has focused on a newly discovered ERP component called the distractor positivity (PD), which is thought to measure an inhibitory attentional process. This collaborative review summarizes previous research relying on this component with a specific emphasis on how the PD has been used to understand the ability to ignore distracting stimuli. In particular, we outline how the PD component has been used to gain theoretical insights about how search strategy and learning can influence distraction. We also review alternative accounts of the cognitive processes indexed by the PD component. Ultimately, we conclude that the PD component is a useful tool for understanding inhibitory processes related to distraction and may prove to be useful in other areas of study related to cognitive control. [ABSTRACT FROM AUTHOR]

In visual search tasks, negative features provide information about stimuli that can be excluded from search. It has been shown that these negative features help participants to locate the target, possibly by attentional suppression of stimuli sharing the negative feature. Attentional suppression is assumed to be reflected in an event-related potential, the PD component. To provide a further test of these assumptions, we presented the color of the distractor at the start of a trial and asked participants to find the other colored stimulus in the subsequent search display. Consistent with attentional suppression, we observed a PD to a lateral distractor shown with a vertical target. However, the PD occurred in this condition only when target and distractor could also be on opposite sides of fixation. The effect of trial context on the PD suggests that the PD reflects a search strategy whereby participants select stimuli opposite to the distractor when trials with opposite placements occur during the experiment. Therefore, the PD to the distractor may in fact be an N2pc to the opposite stimulus, indicating that the distractor is not suppressed, but avoided by redirecting attentional selection to the opposite side. [ABSTRACT FROM AUTHOR]

In visual search, the internal representation of the target feature is referred to as the attentional template. The attentional template can be broad or precise depending on the task requirements. In singleton search, the attentional template is broad because the target is the only colored element in the display. In feature search, a precise attentional template is required because the target is in a specific color in an array of varied colors. To measure the precision of the attentional template, we used a cue-target paradigm where cueing benefits decrease when the cue color differs from the target color. Consistent with broad and precise attentional templates, the decrease of cueing effects was stronger in feature than in singleton search. Measurements of ERPs showed that the N2pc elicited by the cue decreased with increasing color difference, suggesting that attention was more strongly captured by cues that were similar to the target. However, the cue-elicited N2pc did not differ between feature and singleton search, making it unlikely to reflect the mechanism underlying attentional template precision. Furthermore, there was no evidence for attentional suppression as there was no cue-elicited PD, even in conditions where the cueing benefit turned into a same-location cost. However, an index of signal enhancement, the contralateral positivity, reflected attention template precision. In general, there was sensory enhancement of the stimulus appearing at the cued location in the search display. With broad attentional templates, any stimulus at the cued location was enhanced, whereas enhancement was restricted to target-matching colors with precise attentional templates. [ABSTRACT FROM AUTHOR]

Top–down control of attention allows us to resist attentional capture by salient stimuli that are irrelevant to our current goals. Recently, it was proposed that attentional suppression of salient distractors contributes to top–down control by biasing attention away from the distractor. With small search displays, attentional suppression of salient distractors may even result in reduced RTs on distractor-present trials. In support of attentional suppression, electrophysiological measures revealed a positivity between 200 and 300 msec contralateral to the distractor, which has been referred to as distractor positivity (PD). We reexamined distractor benefits with small search displays and found that the positivity to the distractor was followed by a negativity to the distractor. The negativity, referred to as N2pc, is considered an index of attentional selection of the contralateral element. Thus, attentional suppression of the distractor (PD) preceded attentional capture (N2pc) by the distractor, which is at odds with the idea that attentional suppression avoids attentional capture by the distractor. Instead, we suggest that the initial "PD" is not a positivity to the distractor but rather a negativity (N2pc) to the contralateral context element, suggesting that, initially, the context captured attention. Subsequently, the distractor was selected because, paradoxically, participants searched all lateral target positions (even when irrelevant) before they examined the vertical positions. Consistent with this idea, search times were shorter for lateral than vertical targets. In summary, the early voltage difference in small search displays is unrelated to distractor suppression but may reflect capture by the context. [ABSTRACT FROM AUTHOR]