Dissociating between the N2pc and attentional shifting: An attentional blink study

Abstract

The N2pc is routinely used as an electrophysiological index of attentional shifting. Its absence is thus taken as evidence that no shift of attention occurred. We provide evidence in contrast to this notion using a variant of the attentional blink (AB) paradigm. Two target letters, embedded in two streams of distractor letters and defined by their color, were separated by either 300 or 800 ms. The second target was preceded by a distractor frame of the same color (cue). As expected, identification of the second target was poorer at the short than at the long lag (the AB effect). The AB did not affect attentional capture by the cue, but suppressed and delayed the N2pc associated with it. This result suggests that the N2pc does not reflect attentional shifting. Instead, we conclude that the N2pc indexes the transient enhancement that occurs at the spatial focus of attention and promotes high-level processing such as identification. This conclusion calls for a reinterpretation of findings from the attentional capture literature that relied on the N2pc as an index of attentional shifting. Our results also inform contemporary models of the AB.

Covert Spatial Attention Speeds Target Individuation

“…In our experiments, we observed a robust target-evoked N2pc even when we verified with alpha-band activity that observers had precisely attended the target location in advance. This finding is difficult to reconcile with the early view that the N2pc reflects a shift of covert spatial attention to a target stimulus (Eimer, 1996;Woodman and Luck, 1999) but dovetails with other recent evidence that the N2pc can be dissociated from shifts of spatial attention (Zivony et al, 2018). This result can be naturally explained by an individuation account of the N2pc (Mazza and Caramazza, 2015).…”

“…This account is closely related to the individuation account because localization is considered a necessary component of object individuation (Kahneman et al, 1992;Xu and Chun, 2009). Zivony et al (2018) proposed another possibility. Specifically, Zivony et al suggested that the N2pc reflects attentional engagement, which they distinguished from the deployment of spatial attention.…”

Top-down, bottom-up and selection-history-based control of attention: A failed trichotomy? The case of Priming of pop-out (PoP)

“…Accordingly, the N2pc seems to reflect processes akin to what we referred to as attentional engagement in the section titled Processing stages in a typical PoP experiment (see Zivony, Allon, Luria & Lamy, 2018 for related evidence).…”

Spatial cueing effects are not what we thought: on the timing of attentional deployment

“…Finally, PAF suggests a more parsimonious account of the extant findings, as it does not require a distinction between attentional shifts and attentional engagement. In keeping with the core insight of the camera model (Zivony, Allon, Luria & Lamy, 2018;Zivony & Lamy, 2016), PAF also posits that cue validity and compatibility effects can be dissociated and are not two equivalent measures of attentional selection as is often assumed (e.g., Theeuwes et al, 2000). However, according to PAF, these measures do not reflect attentional shifting and engagement, respectively.…”