Infants 8-11 months of age were exposed to repetitions of a 6-tone sequence or melody, then tested for their discrimination of transpositions of that sequence as well as other melodic transformations previously used by Massaro, Kallman, and Kelly with adults. In experiment 1, infants showed evidence of discriminating all transformations from the original melody. In Experiment 2, the task was made more difficult, and infants failed to discriminate transpositions of the original melody as well as transformations that preserved the melodic contour and approximate frequency range of the original melody. By contrast, infants showed evidence of discriminating transformations that violated the contour of the original melody or that included changes in the octaves from which component tones were drawn. This global processing strategy parallels that used by adults with atonal or unfamiliar tonal melodies.

We tested infants 6 to 8 months and children 5 Vi years of age for their discrimination of silent intervals between elements of auditory patterns. Standard patterns consisted of six 200-ms tones, three at 440 Hz and three at 659 Hz, with 200-ms intertone intervals (XXXOOO). Contrasting patterns differed only in the addition of a silent increment following the third tone (i.e., between tone groups, XXX OOO) or following the fourth tone (i.e., within a tone group, XXXO OO). Contrasting stimuli presented to infants had increments of 200, 125, 100, or 75 ms; those presented to children had increments of 100, 75, and 50 ms. Infants detected all increments in all locations except the 75ms increment in the between-group location, but there were no differences in performance for different increment locations. Children detected all increments, but performed significantly worse for between-group increments than for within-group increments. Thus, the context of a temporal increment influences its detectability for children, as it does for adults, indicating that children group the elements of auditory stimuli on the basis of frequency.

Auditory thresholds were determined for infants and adults to half-octave bands of noise centered at 10,000 and 19,000 hertz. Adults were significantly more sensitive than infants at 10,000 hertz, but at 19,000 hertz, adults and infants had comparable thresholds.

Three groups of nine 5-11-month-old infants provided evidence of discrimination of speechlike stimuli differing only in vowel duration. Ease of discrimination was directly related to the magnitude of the ratio of the longer to shorter vowel. Group one infants discriminated three vowel duration contrasts (with ratios of 0.33, 0.67, and 1.0) embedded in a synthetic [mad] syllable; group two discriminated these same duration contrasts within the bisyllable [ samad ], and group three in the trisyllable [ masamad ]. In all cases, the contrasting durations were carried by the last vowel of the synthetic word. These same three infant groups failed to provide evidence of discrimination of a final position released stop consonant contrast ([mat] versus [mad]) cued by voice excitation during closure of the [d] and not the [t]. These results suggest that vowel duration may be a primary cue for infants' perception of the voicing of final position stop consonants.