Within-session changes in operant responding when gerbils (Meriones unguiculatus) serve as subjects

Recent research has demonstrated that rate of responding frequently changes in a robust and systematic manner during experimental sessions in which organisms engage in operant responding. One potential cause for these changes in response rate is that levels of exploration change during experimental sessions and that high levels of exploration interfere with operant responding. Several studies have shown that gerbils (Meriones unguiculatus) explore at a constant rate during experimental sessions. The present study examined the response pattern produced by gerbils responding for food delivered by several simple schedules of reinforcement. Results indicated that robust changes (between 200 and 400%) in response rate occurred during the experimental sessions. These data argue against a role for exploration in the production of within-session changes in operant response rate.