Capture by Context Elements, Not Attentional Suppression of Distractors, Explains the PD with Small Search Displays

Abstract

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.

Attentional Templates Are Sharpened through Differential Signal Enhancement, Not Differential Allocation of Attention

“…Thus, the electrophysiological results suggest that RTs to targets appearing at the same location as the inverted singleton cue were longer because attention was captured by the cue context and not because stimuli at the cued location were suppressed. In summary, the current study and Schönhammer et al (2020) demonstrate that signs of behavioral suppression do not always result from attentional suppression, despite the face value of this interpretation (see also Kerzel & Burra, 2020).…”

PD components and distractor inhibition in visual search: New evidence for the signal suppression hypothesis

“…However, this interpretation of the P D has recently been challenged by results reported by Kerzel and Burra (2020). Using four-item search displays with a task-irrelevant color singleton similar to Gaspelin and Luck (2018a), but without interleaved probe trials, they confirmed the presence of an early positivity contralateral to a lateral color singleton in search displays where the target appeared on the vertical midline and thus did not elicit any lateralized ERP components.…”

“…The N2pc is triggered by search targets and other objects with targetdefining features, and is generally assumed to be a marker of the deployment of attention to these objects (Eimer, 1996;Luck & Hillyard, 1994a, 1994b. Kerzel and Burra (2020) interpreted the contralateral negativity triggered by color singleton distractors in their study as an N2pc reflecting attentional capture by these singletons. This pattern of results is difficult to reconcile with the idea that the preceding contralateral positivity (P D ) reflects active singleton suppression, since it is unclear why a singleton should still be able capture attention after it has been suppressed.…”

Drawn to Distraction: Anxiety Impairs Neural Suppression of Known Distractor Features in Visual Search

“…Neither state nor trait anxiety correlated with RTs in any cueing condition, rs < .22, ps > .15. Kerzel and Burra (2020) proposed that, in small search displays, participants may systematically search lateral positions before vertical positions, even when the lateral item is a distractor. To examine this possibility, we compared RTs with lateral targets versus vertical targets in a 2 (Target Position) × 3 (Cue Type) repeated-measures ANOVA.…”