The proposed research concerns the development of crying in human infants and the development of caregivers' responses to crying. Previous research has often focused on the cry's diagnostic value for newborns, but the proposed research will focus on the value of cry analysis of understanding social and communicative development throughout infancy. The project will help integrate research on infants' cries with theories of social, cognitive, and communicative development, as well as with psychobiological and social-transactional approaches to the study of behavioral development. The broad concerns are how cries affect the events of day-to-day social interactions, and what infants may acquire through participation in these interactions. Social interactions are central to theories of social, personality, and language development in infancy, and thus the proposed work has implications for the etiology of poor developmental outcomes, such as unusual delays in the acquisition of social and communicative skills, failure to thrive, and infant neglect and abuse. The broad goals will be addressed via study of: (1) the developmental relation of cries to other communicative behaviors of infants, such as looking and gesturing; (2) developmental changes in behaviors of mothers in response to their infants' cries; and (3) development changes in the acoustics of the spontaneous cries of normal infants (with particular emphasis on whether the acoustic properties of early, reactive crying may form the basis of sound-meaning correspondence in older infants' sometimes voluntary cries). Two studies are proposed: Study 1 will involve detailed longitudinal analyses of the cry's relation to other communicative behaviors and of the responses of mothers to their infants' cries. Forty- eight infants will be video- and audiotaped in their homes at the ages of 2, 4, 6, 8, 10, 12, 15, and 18 months. Study 2 will involve acoustic analyses of cries according to their communicative functions (e.g., requests, protests). The audiorecordings from Study 1 will be the source of cries for Study 2, and acoustic differences related to age as well as to cry function will be examined.
