Two experiments related to the development of verbal self-control in children were conducted. In the first experiment, 36 adults and 36 four year olds were administered a vocal alone, a motor alone, and a combined-reaction-time task. In the second experiment, 54 kindergarten subjects and 60 fifth-grade subjects were each administered a double…

Seven 18- to 32-month-old children received from seven to 26 experimental sessions each between October 1966 and April 1967. A session lasted from 5 to 15 minutes and concerned control over the verbal responses of the children with token-operated reinforcement devices. In order to make the results of the experimental sessions meaningful, an…