Running and Responding Reinforced by the Opportunity to Run: Effect of Reinforcer Duration

Abstract

The present study investigated the effect of reinforcer duration on running and on responding reinforced by the opportunity to run. Eleven male Wistar rats responded on levers for the opportunity to run in a running wheel. Opportunities to run were programmed to occur on a tandem fixed-ratio 1 variable-interval 30-s reinforcement schedule. Reinforcer duration varied across conditions from 30 to 120 s. As reinforcer duration increased, the rates of running and lever pressing declined, and latency to lever press increased. The increase in latency to respond was consistent with findings that unconditioned inhibitory aftereffects of reinforcement increase with reinforcer magnitude. The decrease in local lever-pressing rates, however, was inconsistent with the view that response strength increases with the duration of the reinforcer. Response rate varied inversely, not directly, with reinforcer duration. Furthermore, within-session data challenge satiation, fatigue, and response deprivation as determinants of the observed changes in running and responding. In sum, the results point to the need for further research with nonappetitive forms of reinforcement.Key words: reinforcer duration, wheel running, lever press, ratsA response-strength conception of reinforcement (de Villiers & Herrnstein, 1976;Herrnstein, 1970) implies that as magnitude of reinforcement increases, the rate of the reinforced response should increase. However, the findings of numerous attempts to demonstrate this relationship using appetitive forms of reinforcement have been equivocal. Previous research into the relationship between reinforcer magnitude and overall response rates in free-operant paradigms using a variety of simple schedules (e.g., fixed interval, fixed ratio, variable ratio, variable interval) with various types of reinforcers (e.g., pellets, grain, sucrose solution) has yielded a confusing array of findings. Overall response rates varied directly

Mapping of functional brain activity in freely behaving rats during voluntary running using manganese-enhanced MRI: Implication for longitudinal studies

“…In the rat, running almost exclusively occurs at night as many other appetitive behaviors (Eikelboom and Mills, 1988). It is generally agreed that wheel running is naturally rewarding and strongly depends on animal motivation to perform this behavior (Belke, 1997;Iversen, 1993;Yu et al, 2005). It has been demonstrated that the pattern of operant responding to gain access to a wheel was similar to those observed for conventionally accepted consummatory reinforces such as food and water (Belke, 1997).…”

“…It is generally agreed that wheel running is naturally rewarding and strongly depends on animal motivation to perform this behavior (Belke, 1997;Iversen, 1993;Yu et al, 2005). It has been demonstrated that the pattern of operant responding to gain access to a wheel was similar to those observed for conventionally accepted consummatory reinforces such as food and water (Belke, 1997). Due to a rather complex nature, wheel running is a highly plastic behavior and can be influenced by a variety of internal and external factors that justify its use in many applications.…”

Dynamic changes in reinforcer effectiveness: Satiation and habituation have different implications for theory and practice

“…For example, if I asked you why you stopped eating (an ingestive behavior), you would probably say that you were full (satiated; e.g., Bizo et al, 1998). If I asked you why you stopped running (an energetic response), you would probably say that you were tired (fatigued; e.g., Belke, 1997). If I asked you why you stopped studying (a cognitive behavior), you might say that you were bored (your attention waned; e.g., Hinson & Tennison, 1999).…”

Aerobic exercise decreases the positive-reinforcing effects of cocaine

“…Similarly, pairing a distinctive environment with the aftereffects of running produces a conditioned place preference in laboratory animals (Lett et al, 2000;Belke and Wagner, 2005). Exercise can also serve as a positive reinforcer, as both laboratory animals (Iversen, 1993;Belke, 1997;2000;Belke and Dunbar, 2001) and in-patient clinical populations (Schebendach et al, 2007) will perform an operant response that leads to the opportunity to exercise.…”