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Abstract

When a conditioned stimulus (CS) is repeatedly paired with a weak unconditioned stimulus (US) prior to being paired with a stronger US in a second conditioning phase, interference, or negative transfer, is often observed during Phase 2. Two conditioned suppression experiments with rat subjects examined the effect of a context switch between phases in this “Hall-Pearce negative transfer paradigm.” In Experiment 1, negative transfer was obtained when the context remained the same for both phases, but there was no evidence of negative transfer when the context was switched between phases. Experiment 2 was designed to control for familiarity with the Phase 2 context, and showed that a context switch between phases again attenuated negative transfer. The effect of context on negative transfer was also similar to its effect on latent inhibition produced under comparable conditions. The results are not consistent with a model proposed by J. M. Pearce and G. Hall (Psychological Review, 87, 532–555, 1980), which ascribes no major role to the context in this situation, but are consistent with A. R. Wagner's (In S. H. Hulse, H. Fowler, & W. K. Honig, Eds., Cognitive Processes in Animal Behavior, pp. 177–209. Hillsdale NJ: Erlbaum, 1978) short-term memory model of conditioning, or with the view that contexts may signal specific CS-US relations. The results extend previous research on other interference paradigms, like latent inhibition and extinction, where context may play a similar role.