Operant Conditioning of Foot Thrusts in Infants and Concomitant Effects on Non-Reinforced Social Behaviors

Abstract

The problem. It has been reported by some investigators that behaviors not directly reinforced increase during the course of operant conditioning with infants. Specifically, smiling and cooing appear to emerge as the result of exposure to operant contingencies designed to increase motor responding. Previous studies have failed to gather objective data on this phenomenon. The purpose of this study is to record smiling and cooing behavior in infants exposed to positive reinforcement for foot thrusts. Procedure. Three two-month-old infants were exposed to a mobile which could be activated by their foot thrusts. During daily ten-minute sessions the rate of foot thrusts and the percentage of five-second intervals in which the infant smiled and cooed were assessed for baseline (stationary mobile) and contingent stimulation conditions. Findings. Of the three subjects, only one learned to operate the mobile by foot thrusts. One subject was dropped from the study after it was learned that he had access to another mobile and another did not condition. For the subject who learned to control the mobile, smiling did not vary systematically across conditions. In contrast to this, cooing clearly increased after a few days of exposure to contingent stimulation. Conclusions. Operant conditioning with infants is not as straightforward as might be assumed, but when it is accomplished, increases in a non-reinforced behavior (cooing) occur in addition to increases in the reinforced responses. Recommendations. Possible explanations for the increased cooing were presented. Further research might be directed to determine which explanation best accounts for this phenomenon.