• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.359-386
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• 2010

In order to evaluate the domain-specific model and process-specific model of spatial and nonspatial working memory (WM), this study manipulated the memory load of the delayed response task and examined how the neural correlates of memory load effect was influenced by the stimulus domain (face and location) at the maintenance stage of WM using an event-related fMRI experiment. One or three face stimuli were presented as target stimuli and participants were asked to maintain the face itself (face WM) or the location of face stimuli (spatial WM). The results of recognition judgment accuracy showed no difference between face WM and spatial WM, and showed equivalent memory load effects of both WM. As a result of brian image analysis, memory load effect at maintenance stage showed that inferior, middle, and superior PFC were recruited by both face WM and spatial WM, and showed that VLPFC was the commonly activated area by both WM, supporting functional specialization of PFC by process components of WM. This study provides evidence for process-specific model in which maintenance of WM is associated with VLPFC.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.216-219
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• 2005

언어 작업기억과 시공간 작업기억이 아동의 글 이해에 미치는 영향을 알아보기 위해 정상 아동과 읽기 지진아동들에게 두 개의 연구를 실시하였다. 연구 1에서는 글의 유형(설명글과 묘사글)별로 글 이해 정도와 언어작업기억과 시공간 잡기장 용량을 측정하여, 정상아동과 읽기 지진 아동 간에 차이가 있는지 알아보았다. 연구 2에서는 글 유형과 2차 기억과제와의 간섭효과를 측정하여 보다 직접적으로 글 유형에 따라 관여하는 작업기억의 종류가 다를 수 있는지를 알아보았다. 두 연구에서 읽기지진 아동은 묘사글을 읽을 때 시공간 작업기억을 사용하는 것을 밝혀내었다.

• Korean Journal of Cognitive Science
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• v.16 no.3
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• pp.155-174
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• 2005

Oh and Kim (2004) and Woodman and Lurk (2004) demonstrated that spatial working memory (SWM) load Interfered concurrent visual search and that search process also impaired the maintenance of spatial information implying that visual search and SWM task both require access to the same limited-capacity mechanism. Two obvious possibilities have been suggested about what this shared limited-capacity mechanism is: common demand for attention to the locations where the items f9r the two tasks were presented (spatial attention load hypothesis), and common use of working memory to maintain a record of locations have been processed(SWM load hypothesis). To test these two hypothetical explanations, Experiment 1 replicated the mutual interference between visual search and SWM task in spite of difference of procedure with preceding researches; possible areas where the items for two tasks were presented were not separated. In Experiment 2, we presented the items for visual search either in the same quadrants where the items for SWM task had appeared (same-location rendition) or in the different quadrants (different-location condition). As a result, search efficiency was more impaired in the different-location condition than in the same-location condition. The memory accuracy was worse in the different-location rendition than in the same-location rendition. Overall results of study indicate that the mutual interference between SWM and visual search might be related to the overload of spatial attention, but not to that of SWM.

• Korean Journal of Cognitive Science
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• v.19 no.2
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• pp.125-142
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• 2008

This study investigated the effects of space- and object-based attention on spatial and visual working memory, by measuring recognition of working memory on the spatial Stroop task including two modalities of attention resource. The similarity condition of stimulus arrangement between working memory task and spatial stroop task was manipulated in order to examine the effects of space-based attention on spatial rehearsal during working memory task, while Stroop rendition was manipulated in order to examine the effects of object-based attention on object rehearsal during working memory task. The results showed that in a condition that stimulus arrangement was highly similar for the spatial working memory task and the spatial Stroop task, recognition accuracy of the spatial working memory was high, but it was not significantly different with the Stroop conditions. In contrast, the recognition accuracy of visual working memory in the incongruent Stroop condition was lower than that in the congruent Stroop condition, but it was not significantly different with the similarity conditions (25% vs. 75%). The results indicated that selective attention has effects on working memory only when resource modality of working memory is the same as that of selective attention.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.605-616
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• 2011

The present study examined memory accuracy for faces with positive, negative and neutral emotional expressions to test whether their emotional content can affect visual working memory (VWM) performance. Participants remembered a set of face pictures in which facial expressions of the faces were randomly assigned from pleasant, unpleasant and neutral emotional categories. Participants' task was to report presence or absence of an emotion change in the faces by comparing the remembered set against another set of test faces displayed after a short delay. The change detection accuracies of the pleasant, unpleasant and neutral face conditions were compared under two memory exposure duration of 500ms vs. 1000ms. Under the duration of 500ms, the accuracy in the pleasant condition was higher than both unpleasant and neutral conditions. However the difference disappeared when the duration was extended to 1000ms. The results indicate that a positive facial expression can improve VWM accuracy relative to the negative or positive expressions especially when there is not enough time for forming durable VWM representations.

• Korean Journal of Cognitive Science
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• v.23 no.2
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• pp.249-267
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• 2012

Individual differences in working memory predict qualitative differences in language processing. High span comprehenders are better able to integrate probabilistic information such as plausibility and animacy, the use of which requires the computation of real world knowledge in syntactic parsing (e.g.,[1]). However, it is unclear whether similar individual differences exist in the use of informative prosodic cues. This study examines whether working memory modulates the use of prosodic boundary information in attachment ambiguity resolution. Prosodic boundaries were manipulated in globally ambiguous relative clause sentences. The results show that high span listeners are more likely to be sensitive to the distinction between different types of prosodic boundaries than low span listeners. The findings suggest that like high-level constraints, the use of low-level prosodic information is resource demanding.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Annual Conference on Human and Language Technology
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• 1991.10a
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• pp.209-218
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• 1991

작업 기억내에서의 통사처리과정을 살펴보기 위해 생략어를 포함하는 네가지 유형의 대등 연결문을 마지작 단어 읽기 과제를 통해 비교하였다. 특히 통사과정에 관한 설명으로 제시되는, 근접 가설, 작업 기억 가설, 최근 필러 이용 가설의 상대적 설명의 효율성을 검증하고자 하였다. 실험 결과는, 주어가 공통논항인, 표준 어순의 연결문이 다른 세 유형의 연결문보다 이해 시간이 빨랐다. 이 결과는 어느 한 가설로는 설명될 수 없으며, 대안적인 설명으로 작업 기억내에서 이용 가능한 여러 정보의 상호 제약에 의해 이루어짐을 논의 했다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.567-571
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• 2009

This study was conducted in order to investigate the role of working memory in word recognition. As a preliminary step in tackling this topic, word frequency and working memory load were manipulated in a naming task. The results showed that word frequency is significantly involved with the working memory load. The effects of working memory load were greater in low-frequency word processing than in high-frequency word processing. These results indicat that working memory is involved more in the processing of low-frequency words. The implications for the teaching of children at the early reading acquisition stage are discussed in this paper.

• Korean Journal of Cognitive Science
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• v.26 no.1
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• pp.27-51
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• 2015

The present study tested the effect of a top-down influence on recalling the colors of Stroop words. Participants remembered the colors of 1, 2, 3 or 6 Stroop words. After 1 second of a memory delay, they were asked to recall the color of a cued Stroop word by selecting out its corresponding color on a color-wheel stimulus. The correct recall was defined when the participants chose a color that was within ${\pm}45^{\circ}$ from the exact location of Stroop word's color on the color-wheel. Otherwise, the recall was defined as incorrect. The analyses of the frequency distribution of the participants' responses in the error trials showed that the probability of choosing the color-name of the target Stroop word was higher than the probability of other five color-names on the color-wheel. Further analyses showed that increasing the number of Stroop words to manipulate memory load did not affect the probability of the Stroop interference. These results indicate that the top-down interference by Stroop manipulation may induce systematic distortion of the stored representation in visual working memory.