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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.26 No.4
Abstract
Working memory(WM) plays an important role in various cognitive tasks. Accordingly, WM training programs have been developed in order to enhance cognitive functions. However, it has been under debate on the effects of the training program. In this study, we performed meta-analyses to test whether WM training programs can improve other cognitive functions based on the domain-specificity of WM. In doing so, we classified previous studies as “congruent” or “incongruent” according to whether the domains of training programs were consistent with those of the measurement tools. As categorized general cognitive task involving measurement task about attention, inhibition, verbal ability and intelligence as well as WM task according to domain specificity, we examined improvement of general cognitive ability when the specific WM domain in the cognitive function was trained. Then, effect sizes were calculated based on statistics reported in the previous studies and meta-analyses were conducted in consideration of measurement periods and participants characteristics. Additionally, Chi square analyses were performed in order to confirm that the domain-specificity could be an important variable in the training effects. The results showed that domain congruency had a great influence on the training effects. The effect sizes were greater when training and measurement domains were consistent than when those were inconsistent, for both of the immediate and follow-up measurements. In addition, the effect of the congruency was greater in the patient groups compared to the normal groups. These findings suggest that the domain-specificity of WM training is an important factor in deciding the effects of the WM training programs.
Abstract
Patients with schizophrenia have difficulty processing visual motion signals including biological motion (BM). A recent fMRI study found altered activation within the posterior superior temporal sulcus in patients with schizophrenia during BM perception. In addition, some frontal areas including ventral premotor cortex are known to be involved in biological motion perception in healthy individuals. However, it is unknown whether patients with schizophrenia have abnormal brain functioning in frontal areas while perceiving biological motion. The present study examined frontal activation associated with biological motion perception in patients with schizophrenia and healthy controls with fMRI data. In healthy controls, a portion of the ventral premotor area and the inferior frontal gyri exhibited specific activation to biological motion stimuli, which was not observed in schizophrenia patients. A dorsal portion of the superior frontal cortex was activated when non-biological motion was misperceived as biological in healthy controls while overall activation level was lower in schizophrenia. Anterior parts of the prefrontal cortex showed suppression during biological motion perception task in healthy controls, whereas no specific activation was observed in the patients with schizophrenia. These results indicate that schizophrenia patients exhibit abnormal frontal brain activation relative to healthy controls in biological motion perception, suggesting altered activities in frontal areas including the mirror neuron system.
Abstract
This study investigated whether or not the length of the time that was given for forming a search target template could affect subsequent search performance in both simple feature search and conjunction search tasks. To accomplish this, we manipulated the inter-stimulus interval (ISI), the time interval between an offset of a pre-cue and subsequent onset of a search array, to 50ms, 500ms and 1500ms in Experiment 1, and to 100ms, 300ms, 500ms and 700ms in Experiment 2. In Experiment 1, the search RTs were rather constant despite the extended ISIs in both the color and orientation simple feature search conditions. However, the RTs became faster as the ISIs were extended in the color-orientation conjunction search condition. In Experiment 2, benefit of the extended ISIs were found in all search conditions when the orientation feature search task was replaced with a Landolt gap search task. Especially, the results showed that search could be faster if the ISIs are extended to maximum 300ms in the simple feature search, whereas if they are extended to maximum 500ms in conjunction search. These results indicate that the type of a target template formed by pre-cues can affect the minimum time to complete a subsequent search task.
Abstract
Research has shown that not only can emotion enhance the processing speed of information, but also cause perceptual biases (e.g. distance, size, time, etc). Previous studies investigated perceptual biases when subjects were consciously exposed to emotion stimuli. In the current study, however, using a size judgment task, we investigated how unconsciously presented emotion stimuli (i.e. do not reach conscious awareness) affect size perception. In Experiment 1, we measured the effects of conscious emotion stimuli on the perceived size of subsequently presented stimuli. The results showed that subjects estimated the size of the subsequently presented stimuli to be larger when preceded by negative emotional stimuli, compared to when preceded by neutral or positive stimuli. Thus only the negative emotion elicited perceptual bias on size perception. In Experiment 2, we measured the effects of unconsciously presented emotion stimuli on size perception of subsequent stimuli. While our results were not identical to that of Experiment 1, the data showed that negative emotion increases variance in size perception of the subsequent stimulus compared to that of neutral and positive emotion. In conclusion, through two experiments, the data indicates that the conscious and unconscious processes of emotion can affect size perception or size judgment in different ways.
Abstract
The accuracy of localization of a briefly presented visual target is compromised when external references are not available. It is thought that in such conditions, localization depends on egocentric cues, such as gaze direction. In the current study, we examined the pattern and magnitude of mislocalization and its underlying mechanism. Human subjects moved a visual probe to report the remembered location of a visual target in an otherwise dark condition. We found that spatial memory was influenced by the very act of localization if a visual probe was used for response. There was a robust bias in localization depending on the initial probe position. When the probe initially appeared on the same side as fixation with respect to the target, the remembered target location was systematically biased beyond the target eccentricity, whereas when the probe initially appeared on the side opposite to the fixation with respect to the target, localization was relatively accurate (Experiment 1). This asymmetric localization bias depending on the initial probe position was robustly found regardless of gaze direction during response period (Experiment 2) and response device (Experiment 3). The pattern of localization bias was consistent with the hypothesis that the perceived target location was repulsed from both the probe and fixation loci. Thus, depending on spatial arrangement, the repulsions from the fixation and probe accumulated to result in a larger localization error overestimating the target eccentricity, or the two repulsions annihilated each other to result in a relatively accurate localization.
Abstract
The side-effect effect (2003a, 2003b, 2004) states that the moral consequence of one’s action influences the inference of intentionality of the action but does not influence the judgments of actor’s intention. The goal of this research was to validate Knobe and Burra (2006)’s argument that the side-effect effect is culture-universal by investigating whether Korean revealed the effect. In this research, we performed three experiments. In Experiments 1 and 2, we looked at the impact of moral consequences of an action on judgments of the actor’s intention (Experiment 1) and on those of intentionality of the action (Experiment 2). The results indicated that the moral consequences of an action mediate both the intention judgments and intentionality judgments. For a morally wrong consequence, Koreans believed that an actor performed an action intentionally but that an actor did not perform an action intentionally for a morally good consequence. Contrary to prediction of the side-effect effect, the same patterns were observed in intention judgments. Experiment 3 tested two alternative hypotheses about Koreans’ moral judgments reported in Experiments 1 and 2, ‘the modified mind-behavior consistency’ hypothesis and ‘the stronger side-effect effect’ hypothesis, The results suggested that ‘the stronger side-effect effect’ hypothesis explain Koreans’ intention and intentionality judgments better than ‘the modified mind-behavior consistency’ hypothesis. Possible implications and limitations were discussed.
Abstract
The current study analyzed the neural signals from the default mode networks (DMN) using the subsequent memory paradigm and a resting-state functional connectivity (rsFC) analysis. Participants learned a number of scenes and faces during functional magnetic resonance imaging (fMRI) and later performed a recognition test. To define the DMN and track the changes in rsFC, resting-state scans were acquired before and after the learning phase. Based on subsequent recognition performance, trials in the learning phase were categorized into either subsequently remembered or subsequently forgotten trials. Here are two main findings: First, DMN subregions showed greater activation for subsequently forgotten than remembered trials. Such subsequent forgetting (SF) effects were most reliable in the right angular gyrus. Second, greater functional connectivity between the hippocampus and the parahippocampal place area (PPA) during the post-learning resting scan predicted better memory for the scenes in the subsequent recognition test. These findings provide information about memory encoding and consolidation functions in the DMN and support the necessity of network-level approaches to understand human memory.
Abstract
Reading the Korean Hanja (logographic) and Hangul (alphabetic) scripts invokes different underlying neural mechanisms based on the degree of grapheme-to-phoneme correspondence (GPC) in the two scripts. This study examined the distinct brain asymmetries in processing Hanja and Hangul scripts of the Korean language according to the Hanja proficiency levels of Korean native speakers. Twenty-five participants were divided into two groups according to their Hanja proficiency levels: High and low groups. Participants performed a lexical decision task (LDT) during the electroencephalogram (EEG) recording. Results revealed differential brain asymmetry patterns according to the participants’ Hanja proficiency levels. The high Hanja proficiency (HP) group showed a larger N400 lexicality effect in the right hemisphere, whereas the low Hanja proficiency (LP) group showed a larger N400 lexicality effect in the left hemisphere during Hanja script recognition. However, no distinct hemispheric asymmetry was observed according to Hanja proficiency levels when participants processed words written in Hangul script. These findings indicate that the processing of Korean Hanja script involves distinct neural processes distinguished from Hangul script processing, whereby different hemispheric specializations are involved according to the Hanja proficiency level of the reader.