Differential reinforcement of other-than-vocalization as a control procedure in the conditioning of infant vocalization rate.

The purpose of the present study is to demonstrate reinforcement control over infant vocalization rates using a DRO schedule to control for elicitation of social stimulation. Mothers of four 2 1/2- to 3-month-old infants provided social reinforcement for their infants' vocalization under two schedules: continuous reinforcement (CRF) and differential reinforcement of other-than-vocalization (DRO). In a repeated-reversal single-subject experimental design, all four infants produced systematically higher vocalization rates during CRF, even though densities of social stimulation during DRO were equal to or greater than densities provided during CRF. Thus, whatever its elicitation value, social stimulation may reinforce infant vocalization rates.