Visual–spatial attention aids the maintenance of object representations in visual working memory

Abstract

Theories have proposed that the maintenance of object representations in visual working memory is aided by a spatial rehearsal mechanism. In this study, we used two different approaches to test the hypothesis that overt and covert visual-spatial attention mechanisms contribute to the maintenance of object representations in visual working memory. First, we tracked observers’ eye movements while remembering a variable number of objects during change-detection tasks. We observed that during the blank retention interval, participants spontaneously shifted gaze to the locations that the objects had occupied in the memory array. Next, we hypothesized that if attention mechanisms contribute to the maintenance of object representations, then drawing attention away from the object locations during the retention interval would impair object memory during these change-detection tasks. Supporting this prediction, we found that attending to the fixation point in anticipation of a brief probe stimulus during the retention interval reduced change-detection accuracy even on the trials in which no probe occurred. These findings support models of working memory in which visual-spatial selection mechanisms contribute to the maintenance of object representations.

A bilateral advantage for maintaining objects in visual short term memory

“…As suggested by Umemoto and colleagues (2010), the emergence of the BFA within VSTM storage may also be attributed to engagement of spatial selection in VSTM rehearsal (e.g. Awh, Jonides & Reuter-Lorenz, 1998;Williams, Pouget, Boucher, & Woodman, 2013). However, since the present findings identified that the BFA in maintenance was contingent on the presence of pre-cues at encoding (Experiment, 4), the findings suggest that the BFA within maintenance may also be influenced by the engagement of selection mechanisms during perception.…”

Alpha-Band Activity Reveals Spontaneous Representations of Spatial Position in Visual Working Memory

“…Past work has shown that observers recognize an item faster and more accurately when it appears at the location where it was encoded than when it appears elsewhere [3–5], thereby suggesting that access to a non-spatial feature is intertwined with spatial memory. Furthermore, Williams and colleagues [28] showed that color WM performance was impaired when observers were prevented from fixating or covertly attending the positions where the memoranda were presented. Thus, spatial attention toward the original locations of the items improved performance in a color WM task.…”

“…Persistent stimulus-specific neural activity is an unambiguous signature of active maintenance in WM [33], and the sustained spatially-selective activity that we observed satisfies this criterion. Furthermore, a broad array of evidence has shown that there is considerable overlap between attention and WM [34–36], such that spatial attention supports maintenance of both locations and non-spatial features in WM [28,37,38]. Thus, while it is difficult to draw a precise line between spatial attention and spatial WM, our findings provide clear evidence that storing non-spatial features in WM elicits the spontaneous and sustained maintenance of an online spatial representation.…”

Pupillary correlates of covert shifts of attention during working memory maintenance

“…There is enhanced visual processing at locations that are currently being held in VWM, similar frontal-parietal regions are activated for spatial attention and VWM, and there are similar ERP effects for spatial attention and VWM (Awh et al, 1998(Awh et al, , 1999(Awh et al, , 2000Jha, 2002;Smyth & Scholey, 1994). More recent research has suggested that overt shifts of attention via eye movements also are implicated in attention-based rehearsal processes (Godijn & Theeuwes, 2012;Theeuwes et al, 2009;Tremblay et al, 2006;Williams et al, 2013). For example, Williams et al (2013) recently demonstrated that during the retention interval of a visual change detection task, participants spontaneously shifted their eyes to locations of items currently being held in VWM even though the screen was blank.…”

“…More recent research has suggested that overt shifts of attention via eye movements also are implicated in attention-based rehearsal processes (Godijn & Theeuwes, 2012;Theeuwes et al, 2009;Tremblay et al, 2006;Williams et al, 2013). For example, Williams et al (2013) recently demonstrated that during the retention interval of a visual change detection task, participants spontaneously shifted their eyes to locations of items currently being held in VWM even though the screen was blank. Thus, similar to the notion that during the retention interval participants covertly shift their attention to locations of items in VWM, when possible participants also will shift their attention overtly to those same locations.…”