Discrimination and response bias for CV syllables differing in voice onset time among children and adults.

A previous experiment demonstrated age-related differences in voice-onset-time (VOT) discrimination when an adaptive procedure was used and trials were concentrated among pairs of stimuli that were discriminated 50% of the time. The major purpose of this experiment was to determine whether the same types of age effects would be replicated for new groups of subjects and a different task in which all stimuli were presented equal numbers of times. An eight-item, five-formant consonant-vowel (CV) continuum in which VOT ranged from 0-35 ms was used. The same-different task presented all possible pairs of CV syllables in which VOT differed by 10 and 20 ms and an equal number of catch trials that contained identical CVs. Results showed that children displayed poorer discrimination than adults for CV pairs differing by both time intervals. Adults displayed a somewhat greater tendency to respond "same" than children. The outcomes supported results of the previous study and were interpreted as representing true age-related differences in VOT discrimination.