Frustration odor of rats receiving small numbers of prior rewarded running trials.

Three related experiments were performed to examine trial-to-trial differences in production of frustration odor during runway extinction by rats that had received 0, 2, 4, or 6 prior rewards. Differences in odor production were indexed by the subsequent speed of escape from the runway goal box by conspecifics. The results indicated that (a) subjects will perform a hurdle-jump response to escape from frustration odor; (b) escape performance even after several prior escape trials accurately reflects trial-to-trial changes in production of frustration odor; and (c) production of frustration odor requires only 4 prior rewards. Implications of the present data for frustration analyses of the limited-trial partial reinforcement effect and future investigations of frustration odor are discussed.