“…It is now well established that conditioned taste aversion, although it can be obtained with CS-US intervals considerably longer than those used in other conditioning paradigms, nevertheless shows an orderly delay-of-reinforcement gradient (e.g., Garcia, Ervin, & Koelling, 1966;Nachman, 1970). The traditional explanation for delay-of-reinforcement phenomena, i.e., that the weaker conditioning at longer CS-US intervals is due to the gradual decay of the CS trace, has difficulty accounting for some of the characteristics of the delay-ofreinforcement gradient in conditioned taste aversion.…”