TRANSFER ACROSS DELAYED DISCRIMINATIONS - II - DIFFERENCES IN THE SUBSTITUTABILITY OF INITIAL VERSUS TEST STIMULI

In 2 experiments, pigeons were trained on, and then transferred to, de layed simple discriminations in which the initial stimuli signalled re inforcement versus extinction following a retention interval. Experime nt 1 showed that discriminative responding on the retention test trans ferred to novel test stimuli that had appeared in another delayed simp le discrimination but not to stimuli having the same reinforcement his tory off-baseline. By contrast, Experiment 2 showed that performances transferred to novel initial stimuli whether they had been trained on- baseline or off-baseline. These results suggest that the test stimuli in delayed simple discriminations acquire control over responding only in the memory task itself. On the other hand, control by the initial stimuli, if coded as outcome expectancies, does not require such task- specific training.