Retraining of extinguished Pavlovian stimuli

Five Pavlovian magazine approach experiments with rat subjects examined the mechanisms by which reconditioning restores extinguished responding. Exper iments 1, 2, and 3 found that retraining did not destroy the spontaneous re covery with the passage of time that is characteristic of extinguished stim uli. Experiments 4 and 5 found evidence that retraining after extinction en hanced the strength of the originally trained associations, Together these results suggest that, just as extinction does not destroy original acquisit ion but superimposes some decremental process, so retraining does not destr oy that decremental process but instead superimposes further associative le arning.