Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Karen G Anderson

Committee Co-Chair

Steven G Kinsey

Committee Member

Elizabeth G Kyonka


The present study assessed temporal control in LEW and F344 rats using a peak-interval procedure, in which fixed-interval (FI) trials were randomly presented with peak-interval (PI) trials, during which the interval was extended and no reinforcement was delivered. The peak time, or the average time at which response rates were the highest, was compared to the FI value as a measure of temporal control across three FI/PI conditions (10/30, 30/90, 60/180 seconds). There were no significant differences in temporal control as assessed by the PI procedure between LEW and F344 rats across three different conditions as well as following acute administration of d-amphetamine. On FI trials, LEW and F344 rats responded differentially across conditions, although there was no main effect of strain. The contingencies of the PI procedure may be so powerful that they override differential effects between these two strains, making it an insensitive measure, although the results of the present study indicate that sensitivity to temporal variables may be exerting some influence over differences in impulsive choice between LEW and F344 rats.