• Science of Emotion and Sensibility
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• v.23 no.1
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• pp.17-28
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• 2020

Lowering observers' view-height may increase the amount of occlusion across objects in a visual scene and prevent the accurate identification of the objects in the scene. Based on this possibility, memory stimuli in relation to their expected views from different heights were displayed in this study. Thereafter, visual short-term memory (VSTM) performance for the stimuli was measured. In Experiment 1, the memory stimuli were presented on a grid-background drawn according to linear perspectives, which varied across observers' three different view-heights (high, middle, and low). This allowed the participants to remember both the color and position of each memory stimulus. The results revealed that testing participants' VSTM performance for the stimuli under a different memory load of two set-sizes (3 vs. 6) demonstrated an evident drop of performance in the lowest view-height condition. In Experiment 2, the performance for six stimuli with or without the grid-background was tested. A similar pattern of performance drop in the lowest condition as in Experiment 1 was found. These results indicated that different view-heights of an observer can change the amount of occlusion across objects in the visual field, and the sensory interference driven by the occlusion may further influence VSTM performance for those objects.

• Korean Journal of Cognitive Science
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• v.23 no.2
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• pp.225-248
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• 2012

The summed-similarity model of visual short-term recognition proposes that the estimated amount of summed similarity between remembered items and a recognition probe determines recognition judgement decision (Kahan & Sekuler, 2002). This study examined the effect of a task-irrelevant location change on the recognition decision against two remembered Gabor gratings differing in their spatial frequencies. On each trial in Experiment, participants reported if two gratings displayed across the visual fields are the same or not as the probe grating displayed after about a second of memory delay. The probe grating would be the same as or different from the memory items (lure) by 1 or 4 JND units. The location of the probe would also vary randomly across the left and right visual field with respect to the location of the corresponding memory item. The participants were instructed to perform their recognition task exclusively to the spatial frequencies of the memory items and the probe while ignoring the potential location change of the probe. The results showed that false-recognition rates of the lure probe increased as the summed similarity between the memory items and the probe increased. The rates also further increased in the condition where the probe location was different from the location of the corresponding memory item compared to the condition where the probe location was the same. The increased false-recognition rates indicate that information stored into visual short-term memory is represented as a form of well-bound visual features rather than independent features.

• Korean Journal of Cognitive Science
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• v.30 no.4
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• pp.239-268
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• 2019

Since last several decades, iconic memory has been accepted theoretically valid for its role of the first storage mechanism in visual memory process. However, there have been relatively less interests in iconic memory among researchers than their interests in visual short- and long-term memory. Such little interests seem to arise from a lack of detailed understandings of theories and methodologies about iconic memory and visual persistence. This study aimed to achieve the understandings by reviewing theories and empirical studies of iconic memory and visual persistence. The study further discussed future direction of iconic memory research according to the essential aspects of phenomenological and ecological criticisms against the validity of iconic memory.

• The Journal of Korean society of community based occupational therapy
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• v.3 no.1
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• pp.67-75
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• 2013

Objective : The purpose of study was to visual scanning program on the effect of visual memory in stroke patients. Method : A single subject experimental research with ABA design was employed in this study. The experiment composed of 15 sessions in total: 5 sessions for baseline, 7 session for visual scanning program, and 3 sessions for the second baseline. Each session for intervention took 30 minutes daily. MVPT, CNT(visual span test, visual learning test) were used for assessment visual perception, visual memory. Result : After visual scanning program, changing faster processing time MVPT 5.5 seconds to 4.5 seconds. Also all itme raw score changes of CNT visual span test, visual learning test. Conclusion : Visual scanning program in stroke patients give a positive impact on the visual memory. To improve stroke patients' perception visual scanning program utilizing visual perception research as well as training programs for a variety of looks forward to being developed.

• 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.

• Korean Journal of Cognitive Science
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• v.32 no.3
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• pp.117-139
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• 2021

The way of change detection in which presence of a different item is determined between memory and test arrays with a brief in-between time interval resembles how visual search is done considering that the different item is searched upon the onset of a test array being compared against the items in memory. According to the resemblance, the present study examined whether varying the probability of change occurrence in a visual short-term memory-based change detection task can influence the aspect of response-decision making (i.e., change prevalence effect). The simple-feature change detection task in the study consisted of a set of four colored boxes followed by another set of four colored boxes between which the participants determined presence or absence of a color change from one box to the other. The change prevalence was varied to 20, 50, or 80% in terms of change occurrences in total trials, and their change detection errors, detection sensitivity, and their subsequent RTs were analyzed. The analyses revealed that as the change prevalence increased, false alarms became more frequent while misses became less frequent, along with delayed correct-rejection responses. The observed change prevalence effect looks very similar to the target prevalence effect varying according to probability of target occurrence in visual search tasks, indicating that the background principles deriving these two effects may resemble each other.

• Proceedings of the ESK Conference
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• 1996.04a
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• pp.191-199
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• 1996

단순 VDT 작업에 의한 인간의 시각정보처리에의 영향을 살펴보기 위하여 특히 서로 다른 model에 대한 정보처리에의 영향을 조사하였다. 피험자는 시각감시 작업과 데이타입력작업을 각각 50분씩 2회 수행하였고 서로 다른 model에 대한 영향을 살펴보기 위해 적업 전, 중 ,후에 걸쳐 MD 및 PD 방법에 의한 과제가 실 시되었다. 실험결과, 단순 VDT 작업이라고 하더라도 작업 수행 내용의 차이에 따라 서로 다른 model에 대한 정보처리에의 영향이 다르게 나타날 수도 있다는 점이 시사되었다.

• Korean Journal of Cognitive Science
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• v.19 no.3
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• pp.311-330
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• 2008

The effect of spatial attention gradually decreases as a function of the distance between the locus of attention and a target. According to this hypothesis, we tested the spatial-effect profile of visual attention when it operates on perception and memory. Experiment 1 measured accuracy of discriminating the color of a simultaneously masked target after presenting a pre-cue to either at the target location or away from the target (perception-intensive task). Experiment 2 measured accuracy of recognizing the color of several items at and around the pre-cued location (memory-intensive task). In the perception-intensive condition, the accuracy gradually dropped as the distance between the cue and target location increases. However, in the memory-intensive condition, subjects remembered only the item at the cued location. This suggests spatial attention in a memory-intensive process would operate on object-based representations. Experiment 2 showed the object-based effect observed in Experiment 1 can be also present in perception under a special circumstance. The results indicate that spatial attention can operate on object-based representations in a memory-intensive process whereas it flexibly can operate either on location-based or object-based representations in a perception-intensive process.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.330-332
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• 2012

시계열 데이터 모델링은 시간 간격의 길이에 따라 단기적인 패턴이 주로 반영된다. 특히, 모델에 마코프 가정을 적용하였을 경우 이전 시간의 값에 따라 현재값이 결정된다. 시계열 데이터의 장기적인 변화를 다루기 위해, 특정 길이의 순차적 패턴을 부호화 하고, 이를 상위 모델의 입력으로 사용하는 과정을 통해 추상화를 시도하고자 한다. 실제로 사람의 감각기억은 200~500 밀리초 가량의 짧은 기억 유지기간을 갖는데, 이 기간의 정보를 상위 처리기의 입력 단위로 보고자 하는 것이다. 이에 본 고에서는 에너지기반 모델링 기법을 이용하여 반복적으로 나타나는 순차적 패턴을 부호화 하는 방법을 제안한다. 이 부호화 방법은 시간 순서에 따른 패턴의 유사도를 이용하여 확률적으로 다음 패턴과의 관계를 표현할 수 있으며, 이는 향후 시계열 데이터를 간략하게 표현하여 분석 및 시각화에 도움을 줄 수 있다.

• Korean Journal of Psychosomatic Medicine
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• v.5 no.1
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• pp.89-96
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• 1997

This study was designed to determine whether cognitive impairment was evident in patients with SLE. Also, it aimed to examine the association of cognitive impairment with other clinical variables. The subjects consisted of 20 patients with mildly active SLE and 20 healthy controls. Methods : A total of 20 SLE patients and 20 normal controls completed a computerized neuropsychological test battery using Vienna Test System. These included Cognitrone test, Continuous attention test, Corsi block tapping test, Standard progressive matrices. Also, neuro-behavioral cognitive status examination was done. The symptom severity of depression was measured with Beck Depression Inventory, Hamilton Depression Rating Scale, and current medications were documented. Disease activity was rated using the SLE diasease activity index (SLEDAI). Results : SLE patients had poorer performance than normal controls on the tests of Cognitrone, attention, nonverbal IQ and memory, independent of age, education, disease activity, steroid use and depression status. Conclusion : Cognitive dysfunction was not uncommon in ambulatory SLE patients as measured by standardized neuropsychological tests. It seemed to occur independently of various clinical variables. These findings would suggest that cognitive dysfunction in SLE may be explained by reflecting subclinical central nervous system(CNS) involvement, rather than coexisting psychological distress due to chronic illness or side effect of medication.