This study examined acoustic correlates of adults' ratings of infants' cries. Parents and nonparents rated 12 spontaneous cries from young infants on 8 items describing the cries' aversiveness and on 9 semantic differential items. The results indicated that the duration, the amount of dysphonation, and proportion of energy in various frequency bands were highly correlated with adults' ratings. Further, the pattern of correlations between each of the 17 rating scale items and the acoustic attributes was virtually the same, suggesting that the items represented a single underlying dimension of perceived aversiveness. Finally, no differences were found between the results for parents and nonparents. General issues in the study of cry perception are discussed.

Adults 1 perceptions of infants' cries were evaluated by means of multidimensional scaling (MDS). Twenty-four nonparents (12 men and 12 women) and 20 parents (10 married couples) made judgments of the similarity of all possible pairs of 12 cries. Subjects also rated the 12 cries on 29 attributes, including perceived aversiveness, possible caretaking responses, affective responses, and semantic differential items. Nonmetric MDS was performed separately for mothers, fathers, nonparent women, and nonparent men. Four-dimensional configurations were interpretable for all groups except nonparent men, and the configurations exhibited strong overall similarity in spite of subtle differences between groups. The fathers' configuration was most similar to the mothers* configuration, and the nonparent women's configuration was most similar to the nonparent men's configuration. Contours of the fundamental frequency and the frequency with the greatest amplitude played a more important role in parents' perceptions of cries than in nonparents 1 perceptions. [Differences in the configurations probably reflected the parents 1 greater experience with infant cries and caregrving.

Women's caregiving and perceptual responses to young infants 1 cries were assessed as a function of parity and cry cause. Ss cared for a crying infant manikin in a simulated baby-sitting situation. Mothers and nonmothers were quite similar in basic features of their caregiving behaviors, suggesting that the effects of parity may be to fine-tune skills that many women bring to the task of caring for young infants. The specific cause of the cry (hunger or pain) was associated with few differences in caregiving behavior, even though a subsequent perceptual task showed that subjects reliably discriminated the two cries. Further analyses of the perceptual data indicated that cry sounds communicate information about the general distress level of the infant better than information about specific causes. Thus, although the sound of the cry may inform caregivers about overall distress level, caregiving behaviors appear to be determined by additional factors.

Two experiments were conducted to test effects of infants' ability to locomote on their social and exploratory behaviors Participants in the first study were 20 normal infants between the ages of 6V2 and 10 months. None of these infants was able to locomote independently. Each was observed, in a standard laboratory environment, for 10 min in an infant "walker" and for 10 min out of the walker. The second study compared effects of walker-assisted locomotion with effects of independent locomotion. Participants were 16 additional infants, all able to creep or crawl. Age parameters were closely similar to those of the first sample Taken altogether, the results indicated that the two modes of locomotion, walker-assisted or independent, afforded similar experiences within a standard environment, but experiences quite different from those of the nonlocomoting infant Some behaviors actually emerged as a function of the ability to locomote, others changed in frequency; still others were extended to new features of the environment In addition, all classes of behaviors measured were known from other studies to affect adults' behavior toward infants. Therefore, changes in these behaviors should lead to changes in infants' social experiences. The systematic reorganization of experiences, both social and nonsocial, as a result of locomotion has implications for social development, and for perceptual, cognitive, and language development as well.A most remarkable event in human infancy is the achievement of independent locomotion: An organism who at first struggles even to lift its face from a surface becomes able, eventually, to propel itself through an environment at will. The salience of independent locomotion stems not only from the sheer contrast that it engenders in infants' behavioral capabilities, but also from its relatively delayed

These studies assessed adults' latencies to signal that they would respond to infant crying as functions of (1) the degree of infant distress they perceived in the cry, and (2) contextual information relevant to caregiving. In the first study (N = 34), listeners waited longer to respond to cries that they had earlier rated as sounding less distressed than when they heard cries of higher distress. Further, those who had been told that the infant needed sleep waited longer to respond than those without this information. This effect of context information, however, was limited to the latencies; in another study (N = 50), listeners' ratings of distress were not affected. Several acoustic features of the cries correlated with distress ratings and with latencies to signal a caregiving response. Taken together, the results suggest that adults' responses to crying are influenced both by acoustic gradations in the cry itself and by the caregiving context. Ratings of degree of distress manifest in the cry, in other words, may be highly predictive of caregiving behavior but not wholly so. Finally, although certain acoustic variations related to greater perceived distress and speed of response, differences were apparent between infants in the magnitude of these variations. The implication that the general process of cry perception may be calibrated, or fine tuned, to the range of acoustic variation provided by individual infants is discussed.