Adults tend to perceive and produce rhythmic structures with simple duration ratios and implied isochrony. If these biases result from long-term exposure to Western metrical structure, they should be evident in North American adults but not in infants. Adult similarity judgments were obtained for alterations of folk melodies that maintained or matched the original metrical structure, whether simple or complex, and for alterations that violated or mismatched the original metrical structure. Adults rated mismatching alterations as less similar than matching alterations, for simple meter patterns, but their ratings of matching and mismatching alterations did not differ for complex meter patterns. Infants, who were tested with a familiarization preference procedure, responded differentially to matching and mismatching alterations for complex as well as simple meter patterns. These findings imply that adult biases reflect long-term exposure to culture-specific metrical structure rather than intrinsic preference for simple meters.

Domain-general tuning processes may guide the acquisition of perceptual knowledge in infancy. Here, we demonstrate that 12-month-old infants show an adult-like, culture-specific pattern of responding to musical rhythms, in contrast to the culture-general responding that is evident at 6 months of age. Nevertheless, brief exposure to foreign music enables 12-month-olds, but not adults, to perceive rhythmic distinctions in foreign musical contexts. These findings may indicate a sensitive period early in life for acquiring rhythm in particular or socially and biologically important structures more generally.development ͉ learning ͉ perception

Children's understanding of emotion in speech was explored in three experiments. In Experiment 1, 4- to 10-year-old children and adults (N = 165) judged the happiness or sadness of the speaker from cues conveyed by propositional content and affective paralanguage. When the cues conflicted (i.e., a happy situation was described with sad paralanguage), children relied primarily on content, in contrast to adults, who relied on paralanguage. There were gradual developmental changes from 4-year-olds' almost exclusive focus on content to adults' exclusive focus on paralanguage. Children of all ages exhibited greater response latencies to utterances with conflicting cues than to those with nonconflicting cues, indicating that they processed both sources of emotional information. Children accurately labeled the affective paralanguage when the propositional cues to emotion were obscured by a foreign language (Experiment 2, N = 20) or by low-pass filtering (Experiment 3, N = 60). The findings are consistent with children's limited understanding of the communicative functions of affective paralanguage.

The study of musical abilities and activities in infancy has the potential to shed light on musical biases or dispositions that are rooted in nature rather than nurture. The available evidence indicates that infants are sensitive to a number of sound features that are fundamental to music across cultures. Their discrimination of pitch and timing differences and their perception of equivalence classes are similar, in many respects, to those of listeners who have had many years of exposure to music. Whether these perceptual skills are unique to human listeners is not known. What is unique is the intense human interest in music, which is evident from the early days of life. Also unique is the importance of music in social contexts. Current ideas about musical timing and interpersonal synchrony are considered here, along with proposals for future research.

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Adults (« = 28) and 8-month-old infants (n = 48) listened to repeated transpositions of a 10note melody exemplifying the rules of Western tonal music. They were tested for their detection of two types of changes to that melody: (a) a 4-semitone change in 1 note that remained within the key and implied dominant harmony (diatonic change) or (b) a 1-semitone change in the same note that went outside the key (nondiatonic change). Adults easily detected the nondiatonic change but had difficulty with the diatonic change. Infants detected both changes equally well, performing better than adults in some circumstances. These findings imply that there are qualitative differences in infants' and adults' processing of musical information. Recently, it has become clear that musical aspects of speech and tonal patterns (e.g., pitch contours, rhythmic patterning) are particularly salient for infant listeners (see Trehub, 1987, 1989, 1990; Trehub & Trainor, in press). For example, infants 5 to 11 months of age readily discriminate tone sequences, or tunes, differing in pitch contour (up/down/same pattern of pitch changes;

Here we show that good pitch memory is widespread among adults with no musical training. We tested unselected college students on their memory for the pitch level of instrumental soundtracks from familiar television programs. Participants heard 5-s excerpts either at the original pitch level or shifted upward or downward by 1 or 2 semitones. They successfully identified the original pitch levels. Other participants who heard comparable excerpts from unfamiliar recordings could not do so. These findings reveal that ordinary listeners retain fine-grained information about pitch level over extended periods. Adults' reportedly poor memory for pitch is likely to be a by-product of their inability to name isolated pitches.

Mothers and fathers sang a song of their choice, once to their infant and once as if to their infant (simulated). The pitch of songs was higher and the tempo slower for infant-directed than for simulated versions. Listeners varying in child-care experience, musical background, and cultural origin reliably identified which of the two versions was infant-directed (Experiment 1). Identification accuracy was enhanced by musical training, knowledge of the singers' language and culture, and by greater pitch and tempo differences between versions. Other adult listeners who rated the singer's emotional engagement assigned significantly higher ratings to infant-directed than to simulated versions (Experiment 2). Differences in pitch and tempo between both versions predicted emotional engagement ratings. Finally, rating differences between infant-directed and simulated versions were highly correlated with identification accuracy.