The time course of attentional selection : an ERP investigation
The N2pc ERP component has been associated with the deployment of visual attention to regions in visual space (Luck & Hillyard, 1994a, Luck & Hillyard, 1994b). Several hypotheses have been advanced regarding what specific aspect of spatially deployed attention the N2pc reflects (Luck & Hillyard, 1994b; Kiss, Velzen, & Eimer, 2008; Tan & Wyble, 2014). One such hypothesis posits that the component reflects the localization of, or orientation to, relevant information in space in preparation of enhancement of sensory processing. In support of this hypothesis, previous research has demonstrated that the N2pc component is eliminated for a target if this target follows a second target in the same location, as a second localization process is unnecessary (Tan & Wyble, 2014). Other research provides evidence that is incongruent with the localization hypothesis. Specifically, a cue that precedes a target in the same location does not eliminate the N2pc for that target, as is predicted by the localization hypothesis (Kiss, Velzen, & Eimer, 2008). However, this study used a cue that was presented 700ms prior to the onset of target information, which may be too large of a temporal window as suggested by contemporary models of attention (Wyble, Bowman, & Nieuwenstein, 2009). The current study tested this localization hypothesis by using a cue within the time course of theoretical models of attention (Wyble, Bowman, & Nieuwenstein, 2009; Olivers & Meeter, 2008; Nakayama & Mackeben, 1989). Analyses revealed that the N2pc elicited by a single target embedded in a stream of distractors is eliminated when preceded by a cue occurring 100ms prior to the target. These results support the hypothesis that the N2pc is elicited by, or after the process of localizing relevant visual information.