Immediate Reinforcement Training Has Moderate Effect on Delay Discounting Behavior in Rats: A Systematic Replication

Previous research has shown that extended exposure to delayed reinforcement results in less impulsive choice in a subsequent delay-discounting task. Some work also suggests the opposite effect: extended exposure to immediate reinforcement may result in more impulsive choice behavior in a subsequent delay-discounting task. Understanding the impact that learning histories have on impulsive choice is important and clinically relevant because of the relationship between a strong preference for smaller-sooner over larger-later reinforcement (i.e., impulsive choice) and a myriad of other problematic health behaviors, such as substance misuse. In the present experiment, we exposed 24 rats to an immediate reinforcement intervention and 24 rats to a maturation/handle control group, followed immediately by a delay-discounting task. The procedure was designed as a systematic replication that accounted for several limitations from recent similar work. Results indicated that exposure to immediate reinforcement modestly increased impulsive choice in the delay-discounting task, but the effect was not overwhelming. These findings are consistent with previous work and have implications for understanding how experience-based interventions may affect clinically relevant impulsive choice.