Adult and child discrimination of CV syllables differing in voicing onset time.

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.