Withinsession changes in response rate: Implications for behavioral pharmacology

An assumption inherent in the theory and practice of operant psychology is that response rate is relatively invariant during steady-state procedures. Recent research has refuted this assumption, demonstrating instead that response rate changes in a large and systematic fashion during many steady-state operant procedures. This finding mandates that operant researchers take into account these within-session changes in response rate when designing and conducting research. Because behavioral pharmacologists use operant techniques and principles, these within-session changes in response rate must be taken into account when conducting behavioral pharmacological research as well. This paper briefly reviews what is known about within-session response patterns and poses the question: Might similar factors contribute to within-session changes in response rate when both drug and nondrug reinforcers are used? Finally, the paper explores some implications of with-in-session changes in response rate for behavioral pharmacology. Behavioral pharmacology is an eclectic field in which practitioners make use of techniques from several traditional areas of psychology. One area to which behavioral pharmacology owes a particularly strong allegiance is the experimental analysis of behavior (i.e., operant psychology