Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Dr. Galen Alessi

Second Advisor

Dr. Alan Poling

Third Advisor

Dr. Malcolm Robertson

Fourth Advisor

Dr. Morry Edwards


The present research was designed to replicate and extend earlier studies with humans and nonhumans in the area of self-control. A discrete trial, within-subject experimental design over multiple sessions, with food as the reinforcer, was used. Instructions did not describe contingencies of reinforcement Subjects were preschool age children, a population that questionably possess the verbal repertoire capable of generating sophisticated tacting, or mediating behavior during long delays. Four experiments consisted of fixed-ratio, concurrent chain schedules with initial and terminal links. Initial links were forced trials, terminal links, choice trials. In Experiment I, the effects of differences in magnitude while holding the delays constant was studied. Experiment II assessed the effects of increasing the delay to the larger reinforcer. In Experiment III, delay to one reinforcer chain was increased while magnitudes remained equal Experiment IV studied the effects of differences in postreinforcement delay while the magnitude of reinforcement remained equal. Results of Experiments I and II showed that all subjects: (a) preferred the larger reinforcer when delay to the smaller reinforcer was equal, and (b) six of seven subjects shifted their preference when delivery of the larger reinforcer was sufficiently removed in time from the choice point The data also suggest that possible tacting of contingencies or waiting strategies did not lead to "maximizing" of reinforcement in Experiment H, with the exception of one subject In Experiment III, two subjects showed preference for the immediate reinforcer upon introduction of a delay to the other equivalent reinforcer. Two subjects showed preference at larger delay values and two remained indifferent In Experiment IV key color bias affected the results. One of three subjects displayed preference for the small post-reinforcement delay without key color bias. All subjects exhibited some verbal repertoire to tact some contingencies and/or make their own rules. For some sessions choice was confrolled by escape/ avoidance/mediating behaviors, lack of motivation for food as a reinforcer, or due to other variables.

Access Setting

Dissertation-Open Access