The effects of deadlines in contingency-specifying stimuli among nine 4 to 5 year old children were investigated. Each child was given verbal statements differing in the specified deadline, the delivery of the reinforcer, and the opportunity to respond. The results indicated: (a) statements not specifying deadlines or reinforcers failed to control the children's behavior reliably, (b) specifying deadlines, either immediate or delayed, and immediate reinforcers exerted reliable control over the children's behavior when the opportunity to respond was immediately available, and (c) specifying delayed deadlines or no deadlines and immediate or delayed reinforcers did not reliably control the children's behavior when the opportunity to respond was delayed.

Three children between the ages of 3 and 3 1/2 were asked to choose a colored object from an array of 5 colors in a baseline condition. After color preferences were established, stickers, small toys and praise were made contingent on choosing the least preferred color. After the first experimental condition resulted in consistent choosing of the least preferred color, a second experimental condition was implemented. At the beginning of each session a contingency-specifying stimulus (CSS) was presented, each CSS specifying a different color to be selected. Both contingency-shaping and CSS presentation resulted in stimulus control over responding. However, CSS presentation resulted in immediate redistributions of behavioral units across CSS sessions.