The effects of context extinction on US signal value

Two experiments with rats examined the effects of context extinction on responding to the signal value of an unconditioned stimulus (US). In Experiment 1, US signal value was first trained when a single food pellet signaled the delivery of three additional pellets. After training, rats received either context extinction (CE) or home cage (HC) exposure before testing US signal value by single food pellet presentations. Results showed responding was significantly reduced in Group CE compared to Group HC. Experiment 2 replicated Experiment 1 and showed that exposure to a different context did not reduce responding to the signal value of a US. The results complement research by Kehoe et al. [Kehoe, E. J., Weidemann, G., & Dartnall, S. (2004). Apparatus exposure produces profound declines in conditioned nictitating-membrane responses to discrete conditioned stimuli by the rabbit (Oryctolagus cuniculus). Journal of Experimental Psychology: Animal Behavior Processes, 30, 259–270.] and have key implications for prominent theories of conditioning.