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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.33 No.3
Abstract
Augmented reality (AR) is one of the essential technologies for the fourth industrial revolution. In AR, virtual objects are embedded in the physical reality and observers can freely interact with virtual objects as well as physical objects. In order to create a realistic and immersive AR environment, three-dimensional (3D) depth perception of virtual objects must be errorless or at least with very little error. However, unlike virtual reality, 3D depth perception of virtual objects in AR has been less studied and the literature shows mixed results as to whether 3D depth perception of virtual objects is overestimated or underestimated. We reviewed 3D depth perception of virtual objects in AR. We discuss in depth how the 3D cues that the visual system uses to calculate or extract 3D egocentric distance (the distance between an observer and an object) may differ in AR. Specifically, binocular disparity and vergence might be the most important cues that cause 3D depth perception errors in AR. We introduce a new display technology, which might provide more immersive AR by resolving some problems in AR such as vergence-accommodation mismatch.
Abstract
It is evaluated whether the P300 amplitude for the probe is greater than the P300 amplitude for the irrelevant in the P300 concealed information test. However, there is a problem that the P300 amplitude for the probe is overestimated because the number of trials of the irrelevant is much larger than that of the probe. Rosenfeld et al. (2008) attempted to solve this problem by reducing the bootstrap sample size of the irrelevant to the sample size of the probe. In general, the bootstrap sample size must be the same as the original sample size and the type 1 error rate becomes smaller than the significance level if the bootstrap sample size is smaller than the original sample size. The purpose of this study is to evaluate the type 1 error rate of the modified bootstrap method that reduces the bootstrap sample size of irrelevant through Monte Carlo studies and to check whether this error can be corrected. As a result of experiment 1, the type 1 error rate of the modified bootstrap method was about .073, which was lower than the significance level .10. The type 1 error rate of the adjusted bootstrap method with corrected the significance level using the standard error was about .140 which was higher than the significance level .10. Consequently, the error of the modified bootstrap method was not corrected. In order to investigate the reason why the error of the modified bootstrap method was not corrected, a Monte Carlo study using numbers was performed. In the results of experiment 2, the type 1 error rate of the modified bootstrap method was about .054, which was less than the significance level .10, and that of the adjusted bootstrap method was about .10, which was the same as the significance level. It was found that the reason why the error of the modified bootstrap method is not corrected was due to the specificity of the EEG data. The reasons why these errors are not corrected and how to solve these errors were discussed.
Abstract
This study investigated the abilities of perspective taking in college students with schizotypal traits using Own Body Transformation (OBT) task and event-related potentials (ERPs). Based on the scores of Schizotypal Personality Questionnaire (SPQ), participants were assigned into the control (n=24) and schizotypal trait (n=22) groups. The OBT task consisted of back-facing (first-person perspective) and front-facing (third-person perspective) conditions where a person wearing a glove on his/her right or left hand. Participants were required to respond to the location of the glove by pressing a response button. The behavioral results of the OBT task showed that the schizotypal trait group exhibited significantly longer reaction times in both the first-person and third-person perspective conditions than the control group. However, the two groups did not differ in the accuracy rates. Both groups also showed significantly longer reaction times and lower accuracy rates in response to the third-person perspective condition than to the first-person perspective condition. In terms of ERPs, the schizotypal trait and control groups showed significantly larger P100 amplitudes in the third-person perspective condition than the first-person perspective condition, and both groups showed significantly larger N200 amplitudes in the third-person perspective condition than the first-person perspective condition. Both groups showed larger P300 amplitudes in the first-person perspective condition than the third-person perspective condition. In addtion, the schizotypal trait group showed significantly longer P300 latencies than control group in both conditions. Finally, a significant negative correlation between disorganization score of the SPQ and P300 amplitude was observed in the schizotypal trait group, and significant positive correlations between the positive score, total score of the SPQ and P300 latency were observed in all participants. Present results indicate that the schizotypal trait group may have difficulties in visuospatial and mental rotation abilities, and that P300 latency could serve as an electrophysiological index of perspective taking.
Abstract
The transposed-letter (TL) effect refers to the phenomenon that nonwords generated by transposing positions of letters in a word are responded more slowly than control nonwords. TL effect has been interpreted as evidence that the coding of letter position is flexible. In Korean, to investigate flexibility of the position coding, more studies are done by transposing syllables since TL effect has rarely been found in Korean. In the present study, the lexical decision data for 588 syllable-transposed nonword and control nonword pairs from the Korean Lexicon Project were analyzed to examine the syllable transposition effect. Hierarchical linear mixed-effects (LME) models revealed that syllable-transposed nonwords were harder to reject than matched controls, which supports the flexible coding of syllable position. The results also showed that the pre-lexical properties of nonwords had significant effects on nonword rejection, but word frequency and word type had no effect on the rejection of nonwords. The results suggest that the locus of transposed-syllable effects in Hangul is pre-lexical.
Abstract
Persons with autism spectrum disorder(ASD) show high rates of comorbidity with intellectual disability(ID). However, previous EEG studies simply compared ASD group to typical developing group without considering comorbidity. The purpose of this study was to compare EEG power of persons with ID to that of persons with ASD comorbid with ID. For this purpose, EEG was measured using a portable 2 channel device, Braino, at rest and during a specific task. Absolute and relative power of various frequency bands were calculated. The results showed that there were no group differences in all frequency bands at rest and in all frequency bands except absolute gamma power during a task. In terms of absolute gamma power, persons with ASD comorbid with ID showed a significantly higher power than that of persons with ID. Theses results suggested that there were similarities in EEG power of ASD and ID, therefore it is necessary to control for ID when conducting EEG power in persons with ASD.
Abstract
It is well known that estimated duration on moving stimulus which is presented about one second might be distorted depending on its spatial features. The distortion disappeared, however, when spatial features of a pair of measuring stimulus are perceived as the same with depth cue. This phenomenon is called time constancy. The aim of the current research is to examine the alternative hypothesis that time constancy is a consequence of size constancy. In the study, Mueller-Lyer illusion was used to measure perceived duration on a pair of stimulus which has the same retinal or perceived motion trajectories. The result shows that estimated duration of the test stimulus was overestimated when the length of perceived trajectories was longer than retinal trajectories compared to that of the standard stimulus and underestimated when the length of perceived trajectory was smaller than retinal trajectory compared to that of the standard stimulus. This implies that distortion in duration perception could be caused even when motion trajectory was perceived the same. This finding is a counterexample against the alternative hypothesis that time constancy might be a consequence of size constancy.
Abstract
This study investigated the method resistant to information leakage in P300-based concealed information test using misleading information and Korean sentences. The misleading information is intentionally introduced to participants as a crime-related item. Participants acquired crime-related knowledge either by committing mock crime (guilty group, n=58) or watching a video that describes a mock crime (informed-innocent group, n=53). Each group was divided into three conditions by exposing to misleading information before the concealed information test : control, 1-misleading information, 2-misleading information. During the concealed information test, the sentence stimuli were presented in subject-object-verb order. There was a significant difference in P300 amplitude between the probe and irrelevant stimuli for object and verb elements regardless of misleading information condition in the guilty group. In the informed-innocent group, the probe stimulus elicited larger P300 amplitude compared to irrelevant stimuli for object and verb elements only in the control condition, but not in the 1-misleading information and 2-misleading information condition. These results suggest that the misleading information in the P300-based concealed information test is effective in reducing false positive outcomes of informed-innocents, even that the number of misleading information increases.
Abstract
We examined how the effects of induced short-term affect on error processing depend on neuroticism. Two groups of neuroticism (high/low) were examined for ERN (error related negativity) and Pe (error positivity) related to error response during the Eriksen flanker task. Short-term affects were induced by presenting one of the emotional (positive/neutral/negative) IAPS pictures immediately before the flanker stimulus was presented in each trial of Eriksen flanker task. Behavioral data showed that error responses were faster than correct responses in two groups, and no difference was observed between high neuroticism group and low neuroticism group. The peak amplitude of ERN was larger (more negative) than CRN (correct response negativity). In particular, the effect of induced affect on ERN amplitude was different according to the level of neuroticism. For the high neuroticism group, the induced negative affect produced a larger amplitude than the neutral affect, but no effect of the induced affect was observed in the low neuroticism group. In addition, the effects of positive affect were not observed in both groups. On the other hand, the peak amplitude and latency of Pe was larger (more positive) and longer than those of Pc (correct positivity), and no effect associated with neuroticism and induced affect was observed. In summary, the effect of induced affect on the early error processing was dependent on the level of neuroticism. The high neuroticism group, unlike the low neuroticism group, showed a larger ERN amplitude when negative affect was induced compared to the neutral affect. These results suggest that high neuroticism group was very sensitive to the induced short-term negative affect which influenced error monitoring. On the other hand, in the later stages of error processing, the induced affect or neuroticism did not have an effect on the error awareness.