The Influence of Vicarious Reinforcement and Habituation on Contingency Learning in Infants

Observational reinforcement in 5- to 13-month-old infants was studied in a contingency learning task where brief light-sound stimulation followed touches on a canister. For all infants, a 3-min contingency period was followed by 3 min of extinction. Before this, four groups had differing preexperiences. One group observed their caregivers receiving continuous reinforcement in the preexperience period; another observed caregivers in a noncontingent task. The third group, a stimulation control, had light-sound events (reinforcers for first group) presented alone without any caregiver responding. The fourth group had no preexperience. During the infant contingency period, only the no preexperience group increased responding in acquisition and had a performance consistent with the occurrence of learning. All three groups with observational preexperience had high response rates initially, which were followed by long-term response declines in the contingency period. The decline was especially steep for infants who observed caregivers in the noncontingent task. Although the evidence for learning by observation was inconclusive, several of the findings supported the influence of habituation during the contingency period following observational preexperience. In extinction, the performance was characterized by further response decreases that were similar for all groups. In summary, observational preexperience had differential effects on the timing of subsequent contingency performance of infants