Biomedical subjects

Min-Shik Kim

Publications and source records attributed to Min-Shik Kim.

4 recordsLinked to original sources

PubMed2005

Concurrent working memory load can reduce distraction.

People have difficulty performing two tasks at once. For example, maintaining items in working memory (WM) makes people more distractible. However, different types of WM load may have different effects on attentional selection depending on whether WM load overlaps with mechanisms involved in target or distractor processing. Three experiments examined the effect of concurrent WM load on Stroop tasks, a widely used measure of executive control and inhibition. Stroop interference increased when the type of WM load overlapped with the type of information required for the target task (experiment 1). In striking contrast, Stroop interference decreased when the type of WM load overlapped with distractor processing (experiment 2). Experiment 3 replicated these results in a different Stroop task. Thus, concurrent WM load does not always impair executive control; performance depends on how contents of WM and task-relevant information overlap. The results highlight how dissociable components of WM interact with perception and executive control.

Attention↗

PubMed2004

Visual search does not remain efficient when executive working memory is working.

Working memory (WM) has been thought to include not only short-term memory stores but also executive processes that operate on the contents of memory. The present study examined the involvement of WM in search using a dual-task paradigm in which participants performed visual search while manipulating or simply maintaining information held in WM. Experiments 1a and 2a involved executive WM tasks that required counting backward from a target digit and sorting a string of letters alphabetically, respectively. In both experiments, the search slopes in the dual-task condition were significantly steeper than those in a search-alone condition, indicating that performing the WM manipulation tasks influenced the efficiency of visual search. In contrast, when information was simply maintained in WM (Experiments 1b and 2b), search slopes did not differ between the single- and dual-task conditions. These results suggest that WM resources related to executive functions may be required in visual search.

Cognition↗

PubMed2004

The role of spatial working memory in visual search efficiency.

Many theories have proposed that visual working memory plays an important role in visual search. In contrast, by showing that a nonspatial working memory load did not interfere with search efficiency, Woodman, Vogel, and Luck (2001) recently proposed that the role of working memory in visual search is insignificant. However, the visual search process may interfere with spatial working memory. In the present study, a visual search task was performed concurrently with either a spatial working memory task (Experiment 1) or a nonspatial working memory task (Experiment 2). We found that the visual search process interfered with a spatial working memory load, but not with a nonspatial working memory load. These results suggest that there is a distinction between spatial and nonspatial working memory in terms of interactions with visual search tasks. These results imply that the visual search process and spatial working memory storage require the same limited-capacity mechanisms.

Exploratory Behavior↗

PubMed2003

Inhibition of return to occluded objects.

Since many visual objects are vulnerable to occlusion, an active process that tracks objects behind occluders confers considerable ecological validity to the visual system. We studied this possibility by testing whether inhibition of return can be observed with occluded objects. In our experiments, two moving objects disappeared or reappeared behind occluders while a cue and a probe were presented. Contrary to the results of a previous study (Tipper, Weaver, Jerreat, & Burak, 1994), responses were consistently delayed for the cued object that was occluded when it was cued (Experiment 1), when it was probed (Experiment 2), or both (Experiment 3). These results suggest that attention can select occluded objects that are out of view. Our findings are in line with prior studies that have demonstrated similar perceptual/attentional effects for occluded objects, as well as for visible objects.

Attention↗