EFFECTS OF STIMULUS CONTINGENCY IN INFANT-ADULT INTERACTIONS

Two experiments manipulated contingent aspects of adult face-to-face d isplays using a TV-replay procedure, after Murray and Trevarthen (1985 ), to examine social-releaser and social-expectancy models of infant s ocial interaction. In Experiment 1, 5-month-olds and their mothers int eracted by viewing each other over closed-circuit television. One grou p of infants (n = 14) viewed a replay of the mothers' behavior during a 90-s period, interposed between two normal 90-s interaction periods; a control group (n = 14) received normal interactions during ail thre e periods. No group differences were obtained, which could be explaine d by either model. In Experiment 2, a stranger interacted with the inf ants to eliminate maternal familiarity as a factor. During three 2-min periods, 4- to 6-month-olds (n = 32) were presented with live-conting ent, televised-contingent, and televised-noncontingent face-to-face in teractions in one of four different orders. Infants gazed less at TV-n oncontingent than either live- or TV-contingent displays, and there wa s evidence that noncontingency had a long-lasting effect on gaze. They were equally attentive to both contingent displays, but smiled more t o live than to televised displays. An order effect revealed that smili ng depended on the nature of both the current and prior interaction. T hese results are more complex than would be predicted by the social-re leaser model. Taken together, the results of the two studies show evid ence that infants form expectancies about interactions based on past e xperience (in Experiment 1, long-term experience interacting with the mother, and in Experiment 2, the initial period of interaction with th e stranger). Violations of these expectancies appear to have a lasting effect on visual attention, but only a temporary effect on smiling.