Electrophysiological evidence for attentional guidance by the contents of working memory

Abstract

The deployment of visual attention can be strongly modulated by stimuli matching the contents of working memory (WM), even when WM contents are detrimental to performance and salient bottom-up cues define the critical target [D. Soto et al. (2006)Vision Research, 46, 1010-1018]. Here we investigated the electrophysiological correlates of this early guidance of attention by WM in humans. Observers were presented with a prime to either identify or hold in memory. Subsequently, they had to search for a target line amongst different distractor lines. Each line was embedded within one of four objects and one of the distractor objects could match the stimulus held in WM. Behavioural data showed that performance was more strongly affected by the prime when it was held in memory than when it was merely identified. An electrophysiological measure of the efficiency of target selection (the N2pc) was also affected by the match between the item in WM and the location of the target in the search task. The N2pc was enhanced when the target fell in the same visual field as the re-presented (invalid) prime, compared with when the prime did not reappear in the search display (on neutral trials) and when the prime was contralateral to the target. Merely identifying the prime produced no effect on the N2pc component. The evidence suggests that WM modulates competitive interactions between the items in the visual field to determine the efficiency of target selection.

Attentional guidance by working memory differs by paradigm: An individual-differences approach

“…(C) Visual working memory capacity task (see Luck & Vogel, 1997); participants reported whether the memory probe color was same or different from the item at that location in the sample array. (D) Automated operation span task (Unsworth et al, 2005); participants alternated between remembering letters and solving arithmetic problems differential modulation of the N2pc event-related potential component) from these two types of paradigms (Carlisle & Woodman, 2011b, 2013Kumar, Soto, & Humphreys, 2009). Taken together, these findings challenge the assumption in this field that both types of paradigms probe the same underlying processes of how WM contents guide attention.…”

Electrophysiological evidence for enhanced representation of food stimuli in working memory

“…We discuss only the ERP results that are relevant to our hypothesis, thus omitting our findings regarding validity as well as validity and task interactions, which have been previously been discussed (Kumar et al 2009). Our main finding was the interaction between task and cue, which was present in all three components of interest: the P3, the LPP and the SPCN.…”

“…This paradigm is useful because it enables us to assess whether the longlatency ERPs modulated by food are affected by factors such as memory or merely attending to the picture. The WM-based guidance paradigm has been examined once before in an ERP study, but there was no examination of different cue types (Kumar et al 2009). In the present study, for the first time, we directly compare food and nonfood cues and examine the modulatory effects of food on late-acting ERP components to provide us insight into the electrophysiological correlates of food-related memory coding and attention.…”

Constraints on task-based control of behaviour following frontal lobe damage: A single-case study

“…Subsequent work has shown that the item held in WM can even influence search for a "pop-out" target (Soto, Humphreys, & Heinke, 2006b), suggesting that there is modulation of early stages of visual processing from information held in WM. Consistent with this Kumar, Soto, and Humphreys (2009) report effects on the N2pc component of the event-related electroencephalography (EEG) response reflecting the fast initial orienting of spatial attention to the side of the display containing a stimulus matching the WM content. Soto, Humphreys, and Heinke (2006a) examined whether this WM effect was apparent in patients with unilateral lesions of the frontal lobe based around the middle frontal gyrus.…”

“…was focused to process another stimulus (Experiment 3), and when the contingency relationship between the cue and target reduced (Experiment 4). We suggest that these are all conditions in which control was expected "externally" triggered through changes in the tasks or in stimulusresponse contingencies (see Kumar et al, 2009).…”