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Biomedical subjects

W L Idson

Publications and source records attributed to W L Idson.

6 recordsLinked to original sources

Temporal course of perceived vowel duration.

The current study explored the temporal course of the perception of vowel duration. A backward recognition masking paradigm was employed in which the subject was to determine which of two target vowels, differing only in duration, was presented on a given trial. The target was followed, after a variable silent intervowel interval, by a masking vowel having one of three possible durations. Subjects were instructed either to identify the long vowel as /i/ and the short vowel as /I/, or were told that the targets were nonsense sounds they were to identify as long or short. For both instruction conditions, identification of the long target improved consistently with increases in the intervowel interval, whereas identification of the short target was equally accurate at the long and the short intervals. Identification of the long target vowel was most accurate when followed by a long masking vowel, whereas identification of the short target vowel was most accurate when followed by a short masking vowel. An information-processing model provided a good description of the quantitative results.

Auditory Perception↗

Backward recognition masking in relative pitch judgments.

Backward recognition masking refers to interference of a second masking tone with recognition of a target tone presented earlier in time. The degree of interference has been found to decrease as the length of the silent interval separating the two tones increases. These results have been interpreted as representing interference of the masking tone upon the preperceptual storage and perceptual resolution of the target. It is logically possible, however, that the masking tone does not interfere with perceptual resolution but interferes with comparison of the target to a long-term memory representation. The current research was designed to provide a critical test of this alternative hypothesis by modifying the backward recognition masking task. Subjects determined whether the masking tone was higher or lower in pitch than the target tone. The frequencies of the target and masking tones varied randomly across trials. This ensured that the task could not be performed by comparing the target to a representation in long-term memory. Nevertheless, masking was obtained in this task, arguing against the comparison argument and in favor of the perceptual resolution interpretation. Given that masking was obtained under both ipsilateral and contralateral presentation of the tones, the results argue for a central preperceptual auditory storage that holds information after the inputs from the two ears are combined in the auditory system.

Functional Laterality↗