Categorization Templates Modulate Selective Attention

Many models of attention assume that categorization (the individuation of events based on the feature dimension relevant for response selection) occurs only after an object has been selected and encoded in working memory (WM). In contrast, we propose that the match between an item and the currently activated set of possible response features (categorization template) already modulates selective perceptual processing prior to WM encoding. To test this proposal, we measured electrophysiological markers of attentional engagement (N2pc components) and behavioral interference effects from posttarget distractors (PTDs) as a function of whether these distractors matched the categorization template. Participants were presented with rapid serial visual presentations (RSVPs) of digits and letters and had to identify a target indicated by a surrounding shape in these RSVP streams. Targets were drawn from a subset of items within an alphanumeric category. Accuracy was highest when the PTD belonged to the irrelevant alphanumeric category, lower when the PTD matched the target's alphanumeric category but not the categorization template, and lowest when the PTD matched the categorization template. On trials with template-matching PTDs, target-elicited N2pc components were temporally extended, indicative of additional attentional amplification triggered by these PTDs. We propose that this amplification produces increased competition between targets and PTDs, resulting in performance costs. These results provide new evidence for the continuous nature of evidence accumulation and attentional modulations during perceptual processing. They show that attentional selectivity is not exclusively mediated by search templates, but that categorization templates also play an important and often overlooked role. Public Significance StatementThe current study suggests that categorization (the process of classifying an object based on current goals) modulates attention, thereby influencing which information will be encoded in working memory. This conclusion challenges long held assumption that categorization occurs only after an object has been selected and encoded. It also broadens our definition of goal-directed attentional control to include features that are relevant to the task but are inefficient in guiding attention.