Hand, arm, and facial actions of young infants to a social and nonsocial stimulus.

Do 9-15-week-old infants produce differentially organized hand and arm actions in relation to affective states when presented with social and nonsocial stimuli? This question was examined by observing 8 infants longitudinally. They were observed when facing their active and passive mother and an active and passive doll during 4 visits at biweekly intervals. Videotapes were coded in real time using the following measures: Vocalization, Gaze, and Gaze Avert; for face, Smiling, Distressed, and Neutral; for hands, Pointing, Open, Curled, and Closed; and for arms, Extended and At Side. Co-occurrence and lag sequential analyses showed that hand actions were organized with other infant actions to form unique behavioral linkages in each of the 4 conditions. The implications of these findings for the development of nonverbal communication are discussed.