Specifying criteria for postulating memory systems.

Abstract

We have examined four criteria commonly used to distinguish separate memory systems: functional dissociation, independent neural systems, stochastic independence, and functional incompatibility. Current evidence fails to jointly satisfy these criteria in establishing independent systems, at least by our assessment. However, the proposed criteria are not all weighted equally in the literature. Certainly dissociation experiments, especially of neuropsychological patients, are weighted strongly in most formulations relative to the other three criteria. If all four criteria are considered equally important, as they should be in our opinion, evidence for the putative systems is much less clear-cut at this point, as indicated in our review.