Thomas Ratkos

Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Jessica E. Frieder

Second Advisor

Dr. Richard W. Malott

Third Advisor

Dr. Cynthia J. Pietras


Match-to-sample, covert behavior, preschoolers, joint control, verbal behavior

Access Setting

Masters Thesis-Abstract Only

Restricted to Campus until



In delayed match-to-sample (DMTS) tasks, a sample stimulus is shown and then removed for some period of time before comparison stimuli are presented. Joint control theory (Lowenkron, 1984, 1988, 1991, 1998, 2006) explains correct selections on delayed match-to-sample tasks in terms of the joint control of behavior by the comparison stimulus and a repeated word or words originating from the sample stimulus. Eight children ages 3 to 6 were exposed to a DMTS task with visual stimuli using a 15s delay. During training, children were taught to name the stimulus cards and then repeat the name of the target stimulus card. It was observed that after training children were able to select the correct stimuli after a delay before they reached phases designed to teach covert mediation. Correct performance persisted when delays were increased and distractor cards were introduced. During the delays, some participants were observed to stop attending to the task and talk about other subjects and still choose correctly, suggesting that verbal rehearsal was not needed for correct responding. These results are interpreted in terms of latent responses and the discriminability of response strength.