Darcheville, J. C., Riviere, V., & Wearden, J. H. (1993). Fixed-interval performance and self-control in infants. Journal of the Experimental Analysis of Behavior, 60, 239-254.

Twenty-six infants, 3 to 23 months old, were trained on fixed- interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch- sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six-phase self- control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5-s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self-controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed-interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self-controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed-interval schedule (classified as pause- sensitive subjects) or produced short pauses and higher steady response rates (classified as pause-insensitive subjects). All pause-sensitive subjects made self-controlled choices in the self- control condition, and all pause-insensitive subjects made impulsive ones.

The authors made a video tape showing an infant boy watching a cartoon ("The Little Brown Bear") on a touch-sensitive screen. Presentation of the cartoon served as the reinforcer for touching the screen under procedures that varied reinforcer delay and duration as outlined in the abstract.

You can view a brief selection (1900K) from the tape in Quicktime format. See JEAB's Video Page for more information.)