关键词: 注意, 视觉工作记忆, 选择机制

Abstract: Visual working memory (VWM) has a strictly limited capacity, necessitating efficient selection mechanisms to prevent irrelevant information from consuming cognitive resources available for targets. Traditional theoretical models propose that once distractors bypass the attentional filter and enter storage, they are assumed to compete with target representations and consequently impair memory performance. However, it remains unclear whether this assumption also applies when distractors share defining features with targets, that is, when they are target-matching distractors. Unlike feature-mismatching distractors, target-matching distractors may engage distinct processing mechanisms due to their feature similarity to the targets. This study investigated the processing of target-matching distractors and their behavioral consequences, testing the hypothesis that they may not be completely filtered out and may interact with target storage in a manner that differs from the traditional resource-competition account.
To isolate the cognitive processing of targets and distractors, we employed a lateralized VWM filtering paradigm across two experiments. Experiment 1 included 28 participants (mean age = 20.04 years), who performed a change-detection task involving memory arrays composed of two target squares and two distractor circles. The experimental conditions manipulated the number of distractors that shared colors with the targets: mismatch (zero), partial match (one), and full match (two). Electroencephalographic (EEG) activity was recorded to examine event-related potentials (ERPs), including the N2pc, an index of attentional selection; the positivity posterior contralateral (Ppc), and contralateral delay activity (CDA), an index of storage-related maintenance. Experiment 2 included 24 participants and adopted a 2 (distractor type: match vs. mismatch) × 2 (presentation probability: high vs. low) within-subjects design. By manipulating the probability of matching trials, this experiment tested whether the effects observed in Experiment 1 reflected strategic processing biases.
In Experiment 1, accuracy was significantly higher in the partial-match condition than in the mismatch condition (p = 0.021). Electrophysiologically, both partial-match and full-match distractors elicited significant N2pc and CDA components, suggesting that they captured attention and engaged storage-related maintenance processes. In contrast, mismatch distractors did not elicit reliable N2pc or CDA components, and early Ppc activity was not consistently modulated by feature matching. Experiment 2 replicated this pattern, demonstrating the robustness of these effects. Accuracy was significantly higher in the match condition (M = 0.91) than in the mismatch condition (M = 0.88, p < 0.001, Cohen's d = 0.47), regardless of presentation probability. ERP analyses further showed that presentation probability modulated early allocation of attention to targets, as reflected by target-elicited N2pc amplitude, but did not alter the storage-related pattern; target-matching distractors consistently elicited reliable N2pc and CDA components, whereas mismatch distractors did not. Together, these findings suggest that target-matching distractors entered storage-related processing but facilitated, rather than impaired, target memory performance.
This study demonstrates that target-matching distractors are processed in a distinctive manner in VWM. Specifically, these distractors are not rigidly suppressed; instead, they are flexibly accommodated by the selection system when they share task-relevant features with targets. Crucially, the inclusion of such task-irrelevant but feature-relevant information in storage-related processing does not necessarily impair performance. Rather, feature overlap between targets and distractors may facilitate target memory. These findings refine traditional accounts of distractor suppression by suggesting that VWM filtering is not purely exclusionary, but is sensitive to the potential relevance of incoming information.

Key words: attention, visual working memory, selection mechanisms