Inability to suppress salient distractors predicts low visual working memory capacity

Abstract

According to contemporary accounts of visual working memory (vWM), the ability to efficiently filter relevant from irrelevant information contributes to an individual's overall vWM capacity. Although there is mounting evidence for this hypothesis, very little is known about the precise filtering mechanism responsible for controlling access to vWM and for differentiating low-and high-capacity individuals. Theoretically, the inefficient filtering observed in lowcapacity individuals might be specifically linked to problems enhancing relevant items, suppressing irrelevant items, or both. To find out, we recorded neurophysiological activity associated with attentional selection and active suppression during a competitive visual search task. We show that high-capacity individuals actively suppress salient distractors, whereas low-capacity individuals are unable to suppress salient distractors in time to prevent those items from capturing attention. These results demonstrate that individual differences in vWM capacity are associated with the timing of a specific attentional control operation that suppresses processing of salient but irrelevant visual objects and restricts their access to higher stages of visual processing.suppression | attention | working memory | event-related potentials | distractor positivity E ach day, human observers perform numerous tasks that require temporary storage of information about objects in the surrounding visual environment. Laboratory studies have revealed substantial variability across neurologically healthy adults in the ability to keep such visuospatial information in mind (1-4). Originally, this variability was attributed to individual differences in the capacity of visual working memory (vWM). According to this account, the maximum amount of information that can be entered into vWM at one time, or the number of "slots" available to store the information, varies across individuals (3,(5)(6)(7)(8). Other contemporary accounts, however, relate the individual differences in vWM performance to variability in attentional control, as well as capacity (9-12). One such attention-based perspective holds that when faced with multiple visual objects, low-capacity individuals have difficulty filtering relevant from irrelevant information (11-15). More specifically, this filtering-efficiency hypothesis proposes that attention regulates the flow of sensory information to the limited-capacity vWM system and that consuming capacity with task-irrelevant information effectively reduces storage capacity for task-relevant items. This hypothesis helps to explain why lowcapacity individuals sometimes store more items in vWM than do high-capacity individuals: whereas high-capacity individuals encode only task-relevant items, low-capacity individuals encode irrelevant items along with task-relevant items (15).Although there is mounting evidence for the filtering-efficiency hypothesis, little is known about the precise mechanism responsible for controlling access to vWM or how its operation differs in low...

Protecting visual short-term memory during maintenance: Attentional modulation of target and distractor representations

“…This revealed no evidence for a selective relationship between the effect of distractor load on target amplitude or distractor amplitudes (all p ’s < 0.25), suggesting that individual differences in how distractor load affected performance did not selectively reflect individual differences in distractor suppression or target enhancement 13 . Instead, individual differences in the effect of distractor load on the relative distribution of attention to target versus distractor locations predicted the effect of distractors on individual performance.…”

Combined Electrophysiological and Behavioral Evidence for the Suppression of Salient Distractors

“…This strategy of using a slightly earlier time window for the P D component than the N2pc component is consistent with several previous studies (e.g., Sawaki & Luck, 2010; Weaver et al, 2017). Relative to the more common mean amplitude measures, positive and negative area measures are typically less impacted by latency differences between subjects (see Luck, 2014) and are therefore more appropriate for assessing correlations with behavioral measures (e.g., see Gaspar et al, 2016). …”

“…The P D often appears exclusively in response to to-be-ignored salient items in the absence of an N2pc component (e.g., Gaspar, Christie, Prime, Jolicoeur, & McDonald, 2016; Gaspar & McDonald, 2014; Jannati, Gaspar, & McDonald, 2013; Sawaki & Luck, 2010, 2011). The P D also has a larger amplitude on fast-response trials than slow-response trials (e.g., Gaspar & McDonald, 2014; Jannati, Gaspar, & McDonald, 2013; McDonald, Green, Jannati, & Di Lollo, 2013), suggesting that suppression of a salient item allows faster detection of the target stimulus.…”

Competition Effects in Visual Cortex Between Emotional Distractors and a Primary Task in Remitted Depression

“…With regard to attentional inhibition, visuospatial working memory (WM) may be important because of its role in an individual’s ability to filter relevant from irrelevant visual information. Research has demonstrated that WM capacity predicts activity in the visual cortex when suppressing distracting information and that individuals with lower WM capacity have difficulty inhibiting attention to task-irrelevant information (34), an effect exacerbated by dysphoria (35). Additionally, there is a well-established link between MDD and WM deficits (36), and evidence that WM training can improve dysphoric individuals’ ability to filter irrelevant information from visual attention (37).…”