ASA 125th Meeting Ottawa 1993 May

4aSP12. Age-related differences in the discrimination of two-formant transitions.

Robert Allen Fox

Fauzia Chaudry

Lida Wall

Div. of Speech and Hear. Sci., Ohio State Univ., 110 Pressey Hall, 1070 Carmack Rd., Columbus, OH 43210-1002

In the past 3 years age-related differences in the ability to process rapidly changing acoustic information (e.g., formant transitions) in making phonetic decisions (e.g., identification of consonants and/or vowels) have been investigated. The data obtained in these studies have been consistent with the claim that older adults as well as children show a decreased ability to process dynamic acoustic information, compared to that of young (college-aged) adults. The present study examines age-related differences in the discrimination of several synthesized two-formant transition and steady-state continua. Two continua represented a [w(small capital eye)]-[w(eh)]-[w(ae ligature)] continuum (differing in terms of the duration of the transition) and the last set of stimuli represented a [b(open aye)]-[d(open aye)] continuum. Three groups of listeners (children 9--12 yrs, young adults 19--25 yrs, and older adults 58--71 yrs) were required to discriminate between two stimulus tokens using a version of Levitt's up--down adaptive procedure. Significant differences were found between the age groups with the lowest jnd's found in the young adults. However, phonological considerations (e.g., changing location of phoneme boundaries across stimulus types) also had a significant effect on jnd's. These data will be discussed with regard to possible explanations of developmental differences (in the case of children) and aging differences (in the case of older adults). [Work supported, in part, by a grant from the National Institute on Aging No. 5R01 AG08353-04.]