Journal of Cognitive Neuroscience
Four models were compared on repeated explicit memory (fragment cued recall) or implicit memory (fragment completion) tasks (Hayman & Tulving, 1989a). In the experiments, when given explicit instructions to complete fragments with words from a just-studied list—the explicit condition—people showed a dependence relation between the first and the second fragment targeted at the same word. However, when subjects were just told to complete the (primed) fragments—the implicit condition—stochastic independence between the two fragments resulted. Three distributed models—CHARM, a competitive-learning model, and a back-propagation model produced dependence, as in the explicit memory test. In contrast, a separate-trace model, MINERVA, showed independence, as in the implicit task. It was concluded that explicit memory is based on a highly interactive network that glues or binds together the features within the items, as do the first three models. The binding accounts for the dependence relation. Implicit memory appears to be based, instead, on separate non interacting traces.