## 4 Discussion
Thus, it may be the case that the presence of an early lateralized waveform could instead be the _positivity posterior contralateral_ (Ppc) component, which may not only be related to a low-level sensory imbalance in the physical structure of search displays by presenting a feature singleton in one hemifield but not the other [54; 55; 56] but also the initial activation on salience maps with a generalized salience signal [57; 58; 59; 55]. Crucially, the results of the early lateralized positive component in the current study confirm that it was indeed the early \(\mathrm{P_{D}}\) that was present, rather than the Ppc because the low-level imbalance of the distractor array was identical in both groups of participants regardless of their differences in state depression. Thus, the only remaining explanation as to why the LSD group only showed a significant early effect of reduced negativity for contralateral (vs. ipsilateral) singletons in both low and high VWM loads is that the efficiency of the top-down mechanism operates to actively suppress the singleton distractor in this group compared to the HSD group. To complement the findings of the early \(\mathrm{P_{D}}\), the distractor was found to trigger N2 pc in the HSD group but not in the LSD group under low-perceptual-load conditions. These findings suggest that individuals exhibiting high levels of depressive symptoms oriented and focused covert attention on the peripheral task-irrelevant singleton features. Therefore, HSD participants, due to their relative deficits in top-down attentional control mechanisms, did not successfully prevent the stimulus-driven attention capture relative to the task-irrelevant singleton's features, which were not part of the current attentional set, compared to their LSD counterparts. Interestingly, individuals with higher depression states did not show a significant magnitude of N2 pc in the high-perceptual-load condition, suggesting an absence of attentional bias toward the task-irrelevant singleton's features when VWMwas strained. Overall, the N2 pc findings for the HSD group demonstrate the influence of perceptual loads on distractor processing, consistent with the predictions of the PLT [9,10]. PLT posits that perception is an automatic process that is dependent on limited perceptual capacity. Consequently, when the perceptual load is low (e.g., encoding one complex object in VWM), the surplus capacity allows for the processing of irrelevant stimuli (i.e., a Chinese character's shape). However, when the perceptual load is high (e.g., encoding four complex objects in VWM), attentional capacity is depleted, effectively preventing distractor processing. Contrary to the direct electrophysiological findings of the current study, our behavioral data did not support the hypothesis that HSD individuals have an impairment in attentional control by hindering the suppression of attentional capture via irrelevant stimuli. We propose that individuals who experience high levels of depressive symptoms may compensate for potential top-down attentional control deficits by allocating more attentional resources to the primary match-to-sample task, enabling them to perform as well as individuals with LSD. This compensatory mechanism has been suggested in previous research, which observed impaired executive control in individuals with high anxiety levels, highlighting the potential limitations of relying solely on behavioral performance measures to identify specific attentional deficits [38,60]. The main behavioral finding of the current study was that regardless of state depression, correct response times in performing match-to-sample tasks were significantly faster for the same distractor positions (compatible) compared to different (incompatible) distractor-to-target horizontal positions, which is suggests the presence of a spatially positive priming (SPP) effect [47]. Thus, it seems that participants' visual-spatial attention was somewhat drawn to the task-irrelevant singleton on the prime display.