Contingent attentional capture by top-down control settings: Converging evidence from event-related potentials.

Abstract

Theories of attentional control are divided over whether the capture of spatial attention depends primarily on stimulus salience or is contingent on attentional control settings induced by task demands. The authors addressed this issue using the N2-posterior-contralateral (N2pc) effect, a component of the event-related brain potential thought to reflect attentional allocation. They presented a cue display followed by a target display of 4 letters. Each display contained a green item and a red item. Some participants responded to the red letter and others to the green letter. Converging lines of evidence indicated that attention was captured by the cues with the same color as the target. First, these target-color cues produced a cuing validity effect on behavioral measures. Second, distractors appearing in the cued location produced larger compatibility effects. Third, the target-color cue produced a robust N2pc effect, similar in magnitude to the N2pc effect to the target itself. Furthermore, the target-color cue elicited a similar N2pc effect regardless of whether it competed with a simultaneous abrupt onset. The findings provide converging evidence for attentional capture contingent on top-down control settings.

Top-down search strategies determine attentional capture in visual search: Behavioral and electrophysiological evidence

“…As expected, behavioral spatial cuing effects indicative of attentional capture were observed on trials where target-color cues were presented. These cues also triggered pronounced N2pc components, confirming findings from previous ERP studies (Eimer & Kiss, 2008;Eimer et al, 2009;Lien et al, 2008) and emphasizing the fact that target-color cues captured attention. The critical question was whether similar behavioral and electrophysiological effects would also be observed for irrelevant-color cues.…”

“…The observation that an N2pc was elicited by physically identical color singleton cues only when their color matched the current task set supports the contingent involuntary attentional capture hypothesis of Folk et al (1992), and demonstrates that capture is not primarily driven by bottom-up salience. In line with the findings of Folk and Remington (1998), these results also demonstrate that, even though targets were singleton items, participants did not use a singleton search mode but instead opted for a more specific dimension or feature-based search strategy (see Eimer et al, 2009, andLien et al, 2008, for additional N2pc evidence of taskset-contingent attentional capture in visual search tasks with nonsingleton targets).…”

“…To gain more detailed insights into the time course of attentional capture and its modulation by top-down task set, a number of recent studies have measured an event-related brain potential (ERP) component as an electrophysiological marker of capture (e.g., Eimer & Kiss, 2008;Eimer et al, 2009;Hickey, McDonald, & Theeuwes, 2006;Lien, Ruthruff, Goodin, & Remington, 2008). The N2pc component, an enhanced negativity over posterior scalp electrodes contralateral to the side of an attended stimulus elicited between 180 and 300 msec after the onset of a visual search array, is assumed to reflect the attentional selection of candidate target items among distractors in visual search tasks (Luck & Hillyard, 1994a, 1994b; see also Eimer, 1996;Girelli & Luck, 1997;Mazza, Turatto, Umiltà, & Eimer, 2007;Woodman & Luck, 1999).…”

The initial stage of visual selection is controlled by top-down task set: new ERP evidence

“…Reliable behavioral spatial cueing effects were found for target-color matching cues, but not for non-matching cues, and the N2pc observed for matching cues was much larger than the N2pc to nonmatching cues. While these observations are in line with previous ERP investigations of contingent attentional capture (e.g., Eimer et al, 2009;Lien et al, 2008), it should be noted that in contrast to these earlier studies, the N2pc to spatially uninformative nonmatching cues was statistically reliable, suggesting that some residual attentional capture was triggered by these cues. This may be a consequence of the design of the current experiment.…”

“…The N2pc component is an enhanced negativity at posterior electrodes contralateral to the visual field where a candidate target stimulus is presented, typically emerges around 200 ms after stimulus onset, and is thought to reflect the spatially selective attentional processing of target objects among distractors in visual search tasks (Luck & Hillyard, 1994; see also Eimer, 1996). This component provides a useful tool to study bottom-up and top-down factors during selective visual attention, and has already been employed in several recent studies of attentional capture, and on both sides of the top-down/bottom-up debate (e.g., Ansorge, Kiss, & Eimer, 2009;Eimer & Kiss, 2010a;Eimer, Kiss, Press, & Sauter, 2009;Hickey, McDonald, & Theeuwes, 2006;Jolicoeur, Sessa, Dell'Acqua, & Robitaille, 2006;Kiss, Jolicoeur, Dell'Acqua, & Eimer, 2008;Lien, Ruthruff, Goodin, & Remington, 2008;Mazza, Turatto, Umiltà, & Eimer, 2007;Wykowska & Schubö, in press). …”