The contents of visual working memory delay the perceived offset of matching visual stimuli

Memory-driven capture during focused visual attention

Attention can be captured by the presence of distractors that match the current content of working memory in the visual field. This memory-driven capture is well established when observers adopt diffused attentional settings prior to the onset of memory-matching distractors. However, it remains unclear whether memory-driven capture can occur when observers are in a state of focused attention. The present study attempted to address this question by examining whether memory-matching distractors can disrupt performance on a focused attention task. Participants were asked to hold a sample word in working memory and then had to name a central color while ignoring an irrelevant distractor word in the visual display. In Experiments 1 and 2, the distractor word was always presented centrally within the focus of attention. In Experiment 3, the distractor word could be presented either at the center or at the periphery (i.e., outside the focus of attention). The results showed that the irrelevant distractor word within the focus of attention interfered with color-naming performance when it matched the sample word held in working memory. However, no interference effect was observed when the distractor word was presented outside the attentional focus. The present findings indicate that working memory-driven capture during a state of focused visual attention depends crucially on whether or not memory-matching distractors are positioned within the focus of attention.

Visual working memory modulates the temporal resolution of visual perception

The present study examined how visual working memory affects temporal resolution of visual stimuli that match the memorised nontemporal information about stimulus features (e.g., shapes). The results show that active maintenance of a sample shape in visual working memory impaired the concurrent detection of a sufficiently brief temporal gap within a matching visual target stimulus. The impairment of temporal gap detection was not likely due to the mechanism of visual priming from the presentation of the sample shape, because there was no evidence for priming effects when the sample was only passively viewed without working memory demands or when the sample was initially encoded into memory but did not need to be actively maintained in mind by the time the target stimulus appeared. These findings demonstrate that visual working memory can lower the temporal resolution of visual perception and thereby impair performance in the temporal gap detection task that requires fine temporal segregation of visual information, and they suggest the existence of a previously unknown downside to the interplay between working memory and visual perception.

Visual working memory enhances target discrimination accuracy with single-item displays

The maintenance of information in visual working memory has been shown to bias the concurrent processing in favor of matching visual input. The present study aimed to examine whether this bias can act at an early stage of processing to enhance target feature perception in single-item displays. Participants were sequentially presented with two distinct colored stimuli as memory samples and a retro-cue indicating which of the two samples should be maintained for subsequent memory test. During the retention interval, they had to discriminate the gap orientation of a Landolt target presented through a single visual stimulus that could match one or neither of the two samples. Across two experiments, we consistently found that discrimination performance was more accurate when the Landolt target was situated within a stimulus that matched the sample being retained in visual working memory, as compared with when the target was not. This effect cannot be attributed to the mechanism of passive priming, because we failed to observe priming effects when the stimulus containing the target matched the sample that was retro-cued to be irrelevant to the working memory task, as compared to when the stimulus matched neither sample. Given the fact that target stimuli were presented in single-item displays wherein external noise was precluded, the present findings demonstrate that the working memory bias of visual attention operating in the absence of stimulus competition facilitates early perceptual processing at the attended location via signal enhancement.