Retrospective revaluation as simple associative learning

Backward blocking, unovershadowing and backward conditioned inhibition are examples of "retrospective revaluation" phenomena, that have been suggested to involve more than simple associative learning. Models of these phenomena have thus employed additional concepts, e.g. appealing to attentional effects or more elaborate learning mechanisms. I show that a suitable representation of stimuli, paired with a careful analysis of the discriminations faced by animals, leads to an account of these and other phenomena in terms of a simple "elemental" model of associative learning, with essentially the same learning mechanism as the Rescorla and Wagner (1972) model. I conclude with a discussion of some implications for theories of learning