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 E Kyonka


Recent investigations focusing on interventions to improve self-controlled choice have centered upon timing processes. However, speculation still remains regarding the mechanism of these interventions. To investigate how these interventions have their effects, timing in mice was assessed using an 18-s peak procedure (18-s FI trials; 54-s peak trials). During an intervention phase, mice in three treatment groups experienced differential reinforcement of low rate (DRL) schedules of reinforcement. A control group received continued exposure to the peak procedure. After 36 DRL sessions, timing was reassessed in the peak procedure. In contrast to previous reports, the DRL intervention resulted in less precise timing as indicated by increased peak spread. It also produced later peak-trial start times and later peak-trial stop times. Thus, it would appear that timing processes may have only been improved in previous reports as a result of assessing timing and choice concurrently and not a result of improvement in timing processes specifically.