Brandi Lee Drisdelle^1,2 (), Martin Eimer²; ¹University of Bristol, ²Birkbeck, University of London

In daily life, we encounter distractions that must be managed to successfully navigate our visual environment. Research has shown that we can avoid attentional capture by highly salient objects in visual scenes, for example, a red object among green objects. Most studies, however, focus on the inhibition of a single salient distractor. Recently, we demonstrated that inhibiting multiple salient distractors is possible (Drisdelle & Eimer, 2023), though it remains unclear whether these distractors influence each other during inhibition. We examined whether salient distractors could be spatially grouped by comparing displays with two salient distractors that were either adjacent or separated by a potential target (search item), using behavioural and electrophysiological measures. Observers searched for a shape-defined target among target-coloured distractors and two different-coloured (salient) distractors. Lateralised ERP activity associated with one salient distractor was isolated by placing one laterally and the other on the midline. The Pd component was used to track the time course of inhibition. Behaviourally, inhibition was measured using the capture-probe paradigm, where observers report probe letters superimposed on all shapes. Our results revealed no difference in the suppression effect (an impaired ability to report letters at the location of a salient distractor) based on whether salient distractors were adjacent or separated, indicating that salient distractors were effectively inhibited in both scenarios. During target search, electrophysiological results showed a reduced Pd amplitude for adjacent compared with separated distractors. We propose spatial grouping occurs when salient items are adjacent: neural activity is distributed across both distractors, eliciting a single Pd that is reduced because midline activity does not contribute to the Pd. In contrast, when salient distractors are separated, each elicits a distinct inhibition process, producing independent Pd components. Our findings demonstrate that salient distractors can influence one another, with perceptual grouping potentially altering underlying neural responses.

Acknowledgements: We acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de recherche du Québec – Nature et technologies (FRQNT) postdoctoral fellowship programs, and grant ES/V002708/1 from the Economic and Social Research Council (ESRC), UK.