Dichotic identification of complex sounds
Judith L. Lauter · The Journal of the Acoustical Society of America · 1980
Ear advantages for sets of speech and nonspeech sounds were measured with four listeners. The speech sounds were: edited fragments of real stop CV syllables, synthetic versions of the full syllables, and six natural vowels. Nine sets of nonspeech sounds were tested; sets differed according to temporal variations in frequency, intensity, duration, and bandwidth. Task was always 6AFC, with a nonverbal response. Results bear on three issues: (1) methodology, (2) expression of results, and (3) the possible acoustical basis for ear advantages. (1) If appropriate methods are used and individual scores retained, ear advantages that are both large (40% difference between ears) and reliable over time can be obtained. (2) The categories of “left, right, and zero” are not sufficient to describe dichotic data; a continuum of ear advantage (25% REA is “more right” than 10% REA) is suggested, which allows comparisons of one listener's performance on several sounds, and comparisons among listeners. (3) Ear advantages seem to reflect the acoustical characteristics of test sounds. For example, right-most ear advantages are observed for multidimensional sounds, or for sounds that include either short-duration elements or changes in bandwidth over time. [Work supported by NINCDS Grant NS03856.]