Signal enhancement and suppression during visual–spatial selective attention

Abstract

Selective attention involves the relative enhancement of relevant versus irrelevant stimuli. However, whether this relative enhancement involves primarily enhancement of attended stimuli, or suppression of irrelevant stimuli, remains controversial. Moreover, if both enhancement and suppression are involved, whether they result from a single mechanism or separate mechanisms during attentional control or selection is not known. In two experiments using a spatial cuing paradigm with task-relevant targets and irrelevant distractors, target and distracter processing was examined as a function of distractor expectancy. Additionally, in the second study the interaction of perceptual load and distractor expectancy was explored. In both experiments, distractors were either validly cued (70%) or invalidly cued (30%) in order to examine the effects of distractor expectancy on attentional control as well as target and distractor processing. The effects of distractor expectancy were assessed using event-related potentials recorded during the cue-to-target period (preparatory attention) and in response to the task-relevant target stimuli (selective stimulus processing). Analyses of distractor-present displays (anticipated versus unanticipated), showed modulations in brain activity during both the preparatory period and during target processing. The pattern of brain responses suggest both facilitation of attended targets and suppression of unattended distractors. These findings provide evidence for a two-process model of visual spatial selective attention, where one mechanism (facilitation) influences relevant stimuli and another (suppression) acts to filter distracting stimuli.

Speed has an effect on multiple-object tracking independently of the number of close encounters between targets and distractors

“…Evidence of distractor suppression has been found in several MOT studies (Flombaum, Scholl, & Pylyshyn, 2008;Pylyshyn, 2006;Pylyshyn, Haladjian, King, & Reilly, 2008; but see Drew, McCollough, Horowitz, & Vogel, 2009) and in other attentional tasks (e.g., Awh, Matsukura, & Serences, 2003;Braithwaite, Humphreys, & Hulleman, 2005;Koshino, 2001;Ogawa, Takeda, & Yagi, 2002). Additionally, several studies using neurophysiological measures have found evidence of both target attentional enhancement and distractor suppression (e.g., Couperus & Mangun, 2010;Hillyard, Vogel, & Luck, 1998;Luck, 1995;Pinsk, Doniger, & Kastner, 2004;Somers, Dale, Seiffert, & Tootell, 1999). Although Bettencourt and Somers conceived the target attentional enhancement and distractor suppression processes as both drawing on a single resource pool, if these processes are characterized as two independent resource pools, then the flexible-resource model would account for the results of the present study.…”

Inhibition in selective attention

“…That is, the vast majority of attention studies reporting increased preparatory alpha activity over irrelevant visual regions used task designs in which foreknowledge about the distractor location or features was accompanied by foreknowledge about the target location or features, such as bilateral displays, rendering it possible that observed effects could also simply reflect attending away or secondary inhibition related to attention to the target . The same is true for studies that used cues that signaled the likelihood of upcoming distraction, but also provided information about the upcoming target, and examined changes in other measures of preparatory activity, such as the cue‐evoked LDAP ERP component …”

Dissociable mechanisms underlying individual differences in visual working memory capacity

“…They reported WMC-related differences in early event-related potentials (ERPs) elicited by task-irrelevant probes at to-be-ignored locations, and interpreted such differences as a deficiency of low-WMC individuals to suppress distracting information. However, attention-related changes in early ERPs seem to reflect both suppression of irrelevant information and enhancement of relevant information (Couperus and Mangun, 2012), making it difficult to judge the relative contribution of these two processes in the Fukuda and Vogel (Fukuda and Vogel, 2009) results. Moreover, the WMC scores and electrophysiological indices of effectiveness of attentional control were derived from the tasks that share many features (e.g., multiple-stimulus arrays and short stimulus presentation times), thus raising concerns about the generalizability of the reported effects to other experimental contexts (cf., Mall et al, 2014), and calling for the need to investigate how attentional control is related to WMC using other typical WMC measures such as complex span tasks (Kane et al, 2004;Unsworth et al, 2005).…”