• Speech Sciences
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• v.8 no.2
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• pp.181-191
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• 2001

The acoustic quality of a vowel is known to be mostly determined by the frequencies of the first formant(Fl) and the second formant(F2). The perceptual(or psychological) dimensions of vowel perception were examined in this study. Also the relationships among perceptual dimensions, acoustical dimensions(Fl & F2), and articulatory gestures of vowel were discussed. Using multi-dimensional scaling(MDS) technique, the experiment was performed in order to identify the perceptual dimensions of the perception of Korean vowel. In the experiment 8 Seoul standard speakers performed the similarity rating task of 10 synthesized Korean vowels. Two-dimensional MDS solution based. on the similarity rating scores was obtained. The results showed that two perceptual dimensions, D1 and D2 were correlated strongly with F2 and F1(r = -.895 and .878 respectively), and were so interpreted as 'vowel advancement' and 'vowel height' respectively. The relationship between the perceptual dimensions of vowel and the articulatory positions of tongue suggested that perception may be directly linked to production. Further research problems were discussed in the .final section.

• Korean Journal of Cognitive Science
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• v.21 no.1
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• pp.177-197
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• 2010

Three experiments compared two hypotheses on visual selection; perceptual load hypothesis and dilution hypothesis. The perceptual load hypothesis predicts that perceptual load of task-relevant processing determines the level of task-irrelevant processing whereas the dilution hypothesis predicts that competition for limited-capacity attentional resource, not perceptual load, determines the locus of selection. To compare the two hypotheses, we investigated the influence of perceptual load in visual search on response interference by a distractor. Experiment 1 and 2 manipulated perceptual load by the set size of a search array and the colors of a target and non-targets, respectively. As a result, distractor interference decreased with a set size regardless of perceptual load. In order to further test the set size effect, Experiment 3 manipulated the perceptual categories of non-targets and a distractor. The results showed that distractor interference decreased only when non-targets belonged to the same category as a distractor. Overall, the current findings support the dilution hypothesis, but not the perceptual load hypothesis, and provide the evidence that visual selection is constrained by capacity-limited, category-specific attentional resources.

• Korean Journal of Cognitive Science
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• v.33 no.1
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• pp.1-22
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• 2022

Lavie's perceptual load theory (Lavie, 1995) proposes that the influence of distractors would be blocked as the load gets higher. Studies of perceptual load have usually adopted the flanker task, developed by Eriksen and Eriksen (1974), which measures reaction time on the target flanked by distractors. In the post-cueing forced task, participants should report the identity of the target cued later, and negative repetition effect (NRE) has often been observed. NRE means the effect that the accuracy of identification is worse when the target is flanked by the same nontargets than when flanked by different nontargets. This study has tried to check whether perceptual load has an effect on identification rate and NRE. Experiment 1 manipulated the similarity between targets and a distractor, and observed a tendency of NRE, but not the effect of perceptual load. Experiment 2 used 4, 2 (in two kinds of diagonal arrangement), or none distractors of the same identity to burden more perceptual load. NRE was significant and perceptual load showed significance but not a linear trend. Experiment 3 checked again whether NRE would be varied according to two levels of perceptual load strengthened by positional variability of load stimuli, but did not find the effect of perceptual load. It is concluded that perceptual load might have a limited effect on the early stage of perceptual processing due to divided attentional processing of the targets briefly exposed. Implications of this study were discussed.

• Speech Sciences
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• v.9 no.1
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• pp.207-215
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• 2002

Perceptual evaluation of duration models of spoken Korean was carried out based on the Classification and Regression Tree (CART) model for text-to-speech conversion. A reference set of durations was produced by a commercial text-to-speech synthesis system for comparison. The duration model which was built in the previous research (Chung & Huckvale, 2001) was applied to a Korean language speech synthesis diphone database, 'Hanmal (HN 1.0)'. The synthetic speech produced by the CART duration model was preferred in the subjective preference test by a small margin and the synthetic speech from the commercial system was superior in the clarity test. In the course of preparing the experiment, a labeled database of spoken Korean with 670 sentences was constructed. As a result of the experiment, a trained duration model for speech synthesis was obtained. The 'Hanmal' diphone database for Korean speech synthesis was also developed as a by-product of the perceptual evaluation.

• Speech Sciences
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• v.9 no.4
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• pp.131-142
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• 2002

Place assimilation in Korean has been argued to reflect the consonantal strength hierarchy in which velar is stronger than labial which is in turn stronger than coronal. The strength relationship has been manifested in two ways in literature. One is through phonological representation as shown in Iverson and Lee (1994). The other is through perceptual salience ranking as suggested by Jun (1995). The goal of this study is to examine the perceptual salience of placed consonants through an identification experiment. The experiment conducted in this study reveals four facts. First, place identification of a prevocalic consonant is higher than that of a postvocalic one. Second, place identification of a stop in coda is more confusable than that of a nasal counterpart in Korean contrary to other previous studies. Third, velar is most confusable in place identification in contrast to Jun (1995) and Hume et al. (1999). Finally, place perception of consonants can vary depending on adjacent vocalic context. These results suggest that perceptual salience is one of the possibly several factors affecting a phonological process.

• Phonetics and Speech Sciences
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• v.10 no.3
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• pp.41-48
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• 2018

This study examined the acoustic characteristics of Korean alveolar fricatives of normal children. Developing children aged 3 and 7, typically produced 2 types of nonsense syllables containing alveolar fricative /sV/ and /VsV/ sequences where V was any one of three corner vowels (/i, a, and u/). Stimuli containing the speech materials used in a production experiment were presented randomly to 12 speech language pathologists (SLPs) for a perception test. The SLPs responded by selecting one of seven alternative sounds. Acoustic measures such as duration of frication noise, normalized intensity, skewness, and center of gravity were examined. There was significant difference in acoustic measures when comparing vowels. Comparison of syllable structures indicated statistically significant differences in duration of frication noise and normalized intensity. Acoustic parameters could account for the perceptual data. Relating the acoustic and perception data by means of logistic regression suggests that duration of frication noise and normalized intensity are the primary cues to perceiving Korean fricatives.

• Korean Journal of Cognitive Science
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• v.15 no.2
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• pp.17-22
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• 2004

Two experiments were executed to investigate the effect of uniform connectedness systematically using the identification task of briefly exposed forms. Previous study observed negative repetition effected (i.e., NRE) in the identification task of two parentheses either connected or disconnected vertically, which was interpreted as an evidence against the hypothesis of uniform connectedness. Experiment I tested the hypothesis that NRE resulted from the Perceptual set or anticipating disconnected displays. Experiment 2 tested the hypothesis that NRE resulted from relatively shorter exposure time. Using partial report task asking participants to report only the cued target and whole report task asking them to report the whole pattern with only connected displays, experiment 1 observed NRE respectively. Experiment 2, with longer exposure time equivalent to 83% accuracy and response bias controlled by use of catch trials, obtained the same NRE. Those results seems to indicate that uniformly connected forms were processed analytically by perceivers without task demand and futhermore, the hypothesis of uniform connectedness as a principle of perceptual organization is not plausible.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.109-118
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• 2010

Using a speeded classification task (Garner, 1978), we investigated the perceptual interaction of distinctive features in Korean consonants. The main questions of this study were whether listeners can perceptually identify the component features that make up complex consonant sounds, whether these features are processed independently or dependently and whether there is a systematic hierarchy in their dependency. Participants were asked to classify syllables based on their difference in distinctive features in the task. Reaction times for this task were also gathered. For example, participants classified spoken syllables /ta/ and /pa/ as one category and /$t^ha$/ and /$p^ha$/ as another in terms of aspiration condition. In terms of articulation, participants classified /ta/ and /$t^ha$/ as one category and /pa/ and /$p^ha$/ as another. We assumed that the difference between their RTs represents their interdependency. We compared the laryngeal features and place features (Experiment 1), resonance features and place features (Experiment 2), and manner features and laryngeal features (Experiment 3). The results showed that distinctive features were not perceived in a completely independent way, but they had an asymmetric and hierarchical interdependency. The laryngeal features were found to be more independent compared to place and manner features. We discuss these results in the context of perceptual basis in phonology.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.4
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• pp.598-609
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• 2014

The increased use of online shopping by older consumers means that online retailers need to consider older consumers when designing websites. We investigated the specific characteristics of commercial websites (i.e., perceptual fluency) through an online experiment. Guided by perceptual fluency and affect optimization literature, hypotheses highlighting older consumers' responses to websites were proposed and tested. Results confirmed that older consumers (in their 50s) are more generous in evaluating online retailers' websites than younger consumers (in their 20s) and that responses to websites are dependent on perceptual fluency. The findings are consistent with previous research and provide additional support for theories that deal with an online apparel shopping context. Practical implications and limitations are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.101-109
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• 2007

In situations of spatio-temporal perception about visuo-auditory stimulus, researches propose optimal integration hypothesis that perceptual process is optimized to the interaction of the senses for the precision of perception. So, when the visual information considered generally dominant over any other sense is ambiguous, the information of the other sense like auditory stimulus influences the perceptual process in interaction with visual information. Thus, we performed two different experiments to certain the conditions of the interacting senses and influence of the condition. We consider the interaction of the visuo-auditory stimulation in the free space, the color of visual stimulus and sex difference of testee with normal people. In first experiment, 12 participants were asked to judge the change in the frequency of audio-visual stimulation using a visual flicker and auditory flutter stimulation in the free space. When auditory temporal cues were presented, the change in the frequency of the visual stimulation was associated with a perceived change in the frequency of the auditory stimulation as the results of the previous studies using headphone. In second experiment, 30 male and 30 female were asked to judge the change in the frequency of audio-visual stimulation using a color of visual flicker and auditory flutter stimulation. In the color condition using red and green. Both male and female testees showed same perceptual tendency. male and female testees showed same perceptual tendency however, in case of female, the standard deviation is larger than that of male. This results implies that audio-visual asymmetry effects are influenced by the cues of visual and auditory information, such as the orientation between auditory and visual stimulus, the color of visual stimulus.