The Effects of Contingent Caregiver Imitation of Infant Vocalizations: a Comparison of Multiple Caregivers.

The present study replicated and extended the Pelaez et al. (Journal of Applied Behavior Analysis 44:33-40, 2011) study, which examined the reinforcing effects of mothers' contingent imitation of their infants' vocalizations. Three infants aged 7-12 months who could vocalize sounds but not words participated with two caregivers for each infant (i.e., triads). During the intervention phase, the caregivers were asked to immediately imitate all vocalizations emitted by the child for a 3-min period. During the yoked control phase, the caregivers listened to an audio recording from the preceding condition and provided vocalizations non-contingently on the infants' responses. The procedures yielded different results across participants; one infant emitted a higher frequency of vocalizations during the contingent imitation phases over the control phases, and the other two infants showed higher rates of responding during the control phases. However, all infants emitted more imitative return vocalizations during contingent reinforcement conditions compared with the yoked control condition.