The purpose of this experiment was to determine whether age-related differences would be observed for discrimination of synthesized, 5-formant consonant-vowel syllables that differed in voicing onset time (VOT) of the initial consonant. Just noticeable differences (JNDs) were measured relative to the end points of the stimulus continuum, using a "same"-"different," adaptive procedure with trial-by-trial feedback/reinforcement and "catch" trials, in which members of the stimulus pair were identical syllables. 6-8-year-old children required significantly longer VOTs for syllabic discrimination than did adults. Adults' JNDs relative to [pa] at the end of the stimulus continuum with longer VOTs were significantly larger than their JNDs relative to [ba], as would be expected on the basis of psychoacoustic considerations, but neither 6-8-nor 8-11-year-old children showed this trend. Performance on "catch" trials for both groups of children was significantly poorer than for adults. Outcomes corresponded to results of other investigations that have reported that children require more acoustic information than adults to achieve the same performance criterion.

The purpose of this experiment was to determine whether age-related differences would be observed among adults in the identification and discrimination of synthesized 5-formant consonantvowel syllables in which the voiced-stop consonants varied in the place-of-articulation feature. Listeners were aged 18-23 and 60-75 years, and all had pure-tone averages :s 25.dB HL. The older listeners exhibited poorer syllable identification thresholds, more shallow identification functions, larger just noticeable differences, and poorer free response performance than younger listeners. Among the older listeners, those with high-frequency sensitivity~30 dB HL at 4 kHz had poorer free responses to syllables than those with better 4-kHz thresholds. In other respects, high frequency sensitivity did not discriminate among older listeners. Explanations considered as accounting for the observed age-related differences included frequency discrimination, since sensitivity, alone, did not account for the results.To study developmental changes in perception, one technique involves the use of a continuum of synthesized consonant vowel (CV) syllables in which the voiced stop consonants differ along the dimension of place of articulation. When Elliott, Longinotti, Meyer, Raz, and Zucker (1981) measured the smallest between-syllable difference that could be discriminated (here termed, "just noticeable differences," or JNDs), they found that normalhearing 6-year-old children had larger JNDs than normal to-year-olds or normal adults. In other work, which used only the three exemplars [bo], [do], and [go], Elliott, Longinotti, Clifton, and Meyer (1981) found that 6-year-old children required higher intensities to identify these syllables and also exhibited more shallow slopes for their performance-intensity functions than did 10-year-oIds. The finding that young children had higher syllableidentification thresholds agreed generally with results showing that young children require higher levels than adults to identify very familiar words (Elliott et al., 1979, Elliott & Katz, 1980. The mechanism that underlies the shallow slopes of performance-intensity functions for certain population groups is unknown.Another study (Elliott & Busse, 1985a) revealed that 60% of severely learning-disabled young adults showed abnormal JNDs. Indeed, their JNDs for the [bu, do, go] continuum resembled the performance of normal6-yearolds. Performance of the learning-disabled young adults on the identification tasks showed considerable betweenPortions of this research were supported, in part, by NSF Grant PFR 79-06496.The authors' mailing address is: Human Communication Sciences, Department of Communicative Disorders, Northwestern University, Frances Searle Building, 2299 Sheridan Rd., Evanston, IL 60201. subject variability. Some exhibited performance-intensity slopes that were steeper than their normal age-mates, but some demonstrated very shallow slopes. Only one of the learning-disabled adults had auditory sensitivity that was poorer than that of the normal c...

The purpose of this experiment was to determine whether age-related differences would be observed for discrimination of synthesized, 5-formant consonant-vowel syllables that differed in voicing onset time (VOT) of the initial consonant. Just noticeable differences (JNDs) were measured relative to the end points of the stimulus continuum, using a "same"-"different," adaptive procedure with trial-by-trial feedback/reinforcement and "catch" trials, in which members of the stimulus pair were identical syllables. 6-8-year-old children required significantly longer VOTs for syllabic discrimination than did adults. Adults' JNDs relative to [pa] at the end of the stimulus continuum with longer VOTs were significantly larger than their JNDs relative to [ba], as would be expected on the basis of psychoacoustic considerations, but neither 6-8-nor 8-11-year-old children showed this trend. Performance on "catch" trials for both groups of children was significantly poorer than for adults. Outcomes corresponded to results of other investigations that have reported that children require more acoustic information than adults to achieve the same performance criterion.

Both 6-year-old children and adults showed as good performance on a syllable identification task for a test condition having more trials per test run and a lower overall level of positive reinforcement as they did for a condition with fewer trials per test run and a higher, overall level of positive reinforcement. Differences between identification thresholds of children and adults are interpreted as reflecting age-related differences in speech processing rather than differences in responding to the test situation.

Forty-two normal older adults, aged 60–75 years, were tested on a battery that included the Speech Perception in Noise (SPIN) test, conventional, and experimental pure tone sensitivity, the W-22 test in quiet and noise, open- and closed-set identification of synthesized syllables that differed in the place of articulation feature, syllable discrimination, the Block Design subtest of the WAIS and the Concept Formation subtest of the Woodcock-Johnson Psychoeducational Battery. Results showed considerable variability on all measures. Only performance on the W-22 Test in noise and sensitivity at 4 kHz were significantly related to absolute levels of performance on low- (LP) and high-predictability (HP) SPIN test sentences. No test variables were significantly related to relative performance on HP and LP sentences. The differing patterns of results for different subjects of this homogeneous sample having excellent language skills suggested that: (1) a larger study in which linguistic abilities were systematically manipulated might produce a different outcome and (2) data for 400–500 similar older adults might show significant but differing patterns of processing auditory stimuli, particularly in the extent to which cognitive processes contribute to listening. [Work supported, in part, by NSF.]