Are Conditioning Laws General? W. J. Wilson, Psychology March 30, 2015 Taste Aversion Learning ⇒ Problems Garcia’s taste aversion seemed to differ from traditional Pavlovian conditioning: • 1-trial learning • long CS-US interval 1-trial Learning . . . is not uncommon e.g., passive avoidance (Wilson & Cook, 1994) Examined effects of ACh-blocker scopolamine on passive avoidance in rats. • Scop impaired acquisition. • Scop impaired recall. • No evidence of state-dependent effects. Long CS-US Interval Revusky: long CS-US delay explained by no interference. Lett: long delay learning in T-maze if interference was prevented. Learned Safety? Does pre-exposure teach • food is safe? • latent inhibition? Best(1975) → Latent Inhibition • Sacc + Saline → No Illness • Saline → Illness. • — Sal becomes CI. • Or, Saline pre-exposuse then ⇑. • Pre-exp caused Latent Inhibition. Reinforcer Re-valuation Change hedonic value of US after learning? • e.g., pair taste with morphine, which leads to aversion, then make the rat an “addict” such that it desires morphine. • Aversion to taste is still there. • (Compare this to the “Klaxon” study.) Compound Potentiation • Recall overshadowing: less salient stimulus gets no associative strength — more salient CS gets it all. • Odor - illness learning very difficult • BUT: Taste + Odor leads to strong aversion to odor. Where is overshadowing? • Sometimes overshadowing does occur, and sometimes potentiation happens in other kinds of learning. Relative Validity • AX+ BX- (correlated condition) • AX+ AX- BX+ BX- (uncorrelated condition) • When X is tested, more CRs to X in uncorrelated than in correlated, even though in both cases X is reinforced 50% of time. • Holds across many species: honeybees choose uncorrelated Orange • Totally unpredicted by R-W Successive Negative Contrast Or, Crespi effect • Small reward seems even smaller if it was preceded by a large reward. • Crespi (1942) rats running for 256 pellets run slower when switched to 16 than do rats running for 16 all along (“depression”) • Rats running for 1 run faster when switched to 16 than do rats running for 16 all along (“elation”). • Negative contrast happens in honeybees and rats, but oddly, not goldfish.