A Bayesian model for implicit effects in perceptual identification

Retrieving effectively from memory (REM; R. M. Shiffrin & M. Steyvers, 1997 ), an episodic model of memory, is extended to implicit memory phenomena. n amely the perceptual identification studies reported in R. Ratcliff and G. McKoon (1997:), In those studies, the influence of prior study was greatest when words were presented most briefly and when forced-choice targets and foils were most similar. R. Ratcliff and G. McKoon use these data to argue against models in which prior study changes a word's representation. A mode l in which prior study changes a word's representation by adding context in formation is fit to their data; at test, the model uses a Bayesian decision process to compare the perceptual and context features associated with the test flash to stored traces. The effects of prior study are due to matchin g extra context information and are larger when alternatives share many fea tures. thereby reducing noise that attenuates these effects.