A simulation model of episodic memory, MINERVA 2, is applied to the learning of concepts, as represented by the schema-abstraction task. The model assumes that each experience produces a separate memory trace and that knowledge of abstract concepts is derived from the pool of episodic traces at the time of retrieval. A retrieval cue contacts all traces simultaneously, activating each according to its similarity to the cue, and the information retrieved from memory reflects the summed content of all activated traces responding in parallel. The MINERVA 2 model is able to retrieve an abstracted prototype of the category when cued with the category name and to retrieve and disambiguate a category name when cued with a category exemplar. The model successfully predicts basic findings from the schema-abstraction literature (e.g., differential forgetting of prototypes and old instances, typicality, and category size effects), including some that have been cited as evidence against exemplar theories of concepts. The model is compared to other classification models, and its implications regarding the abstraction problem are discussed.How is abstract knowledge related to specific experience? In present-day terms, this question concerns the relationship between episodic and generic memories. This article explores the possibility that there is only one memory system, which stores episodic traces, and that abstract knowledge as such does not have to be stored but can be derived from the pool of traces of specific experiences at the time of retrieval. I demonstrate how this might work by applying a simulation model of a multipletrace memory theory to the sehema-abstraction experimental paradigm, which is widely believed to capture in the laboratory the processes by which generic or abstract ideas are formed.Multiple-trace theories assume that each event to which one attends gives rise to its own memory trace. Thus, repetition of an item such as a word in a list does not strengthen a prior representation (i.e., one predating the experiment or one laid down by the item's first experimental occurrence); rather, it produces a new trace that coexists in memory with traces of other occurrences of the same item. Experiments supporting the multiple-trace assumption have been primarily concerned with the ability of subjects to remember an item's presentation frequency, list membership, presentation modality, exposure duration, serial position, and so forth (e.g., Hintzman, 1976;Hintzman & Block, 1971;Hintzman, Block, & Summers, 1973; Hintzman, Grandy, & Gold, 1981;Hintzman, Nozawa, & Irmscher, 1982). These are all episodic memory tasks, and multipleThis article is based on a talk presented at the conference on the Priority of the Specific, Elora, Ontario, Canada, June 1983. The research was supported in part by National Science Foundation Grants BNS-7824987 and BNS-8403258 and in part by a fellowship to the author from the James McKeen Catteli Fund.Thanks are due to the MRC Applied Psychology Unit, Cambridge, England, for the use of ...

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An overview of a simulation model of human memory is presented. The model assumes:(1) that only episodic traces are stored in memory, (2) that repetition produces multiple traces of an item, (3) that a retrieval cue contacts all memory traces simultaneously, (4) that each trace is activated according to its similarity to the retrieval cue, and (5) that all traces respond in parallel, the retrieved information reflecting their summed output. The model has been applied with success to a variety of phenomena found with human subjects in frequency and recognition judgment tasks, the schema-abstraction task, and paired-associate learning. Application of the model to these tasks is briefly summarized.This article summarizes simulation work I have been doing to test the adequacy of some theoretical ideas about human memory. The model, named MINERVA 2, makes just a few basic assumptions; but despite this simplicity, it can be applied to a variety of memory phenomena that have been uncovered in several tasks. This paper is only a preliminary account of the work done to date. More complete reports of the capabilities of MINERVA 2, including the work summarized here, are in preparation.Of central concern in this research has been the question of whether one needs to assume two different memory systems in order to account for memory for individual experiences, on the one hand, and memory for abstract concepts, on the other. MINERVA 2 represents an attempt to account for data from both episodic and generic memory tasks within a single system.The theory behind the simulation model is primarily concerned with long-term or secondary memory (SM), although it also assumes that there is a temporary working store or primary memory (PM) that communicates with SM. Interactions between the two stores are limited to two elementary operations: PM can send a

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L. L. Jacoby, J. P. Toth, and A. P. Yonelinas (1993) advocated a process-dissociation procedure for estimating the contributions to task performance of consciously controlled (R) versus automatic (A) memory processes. The procedure relies on the strong assumption that memory-guided performance attributable to R is stochastically independent of that attributable to A. Violations of this independence assumption can produce artifactual dissociations between estimates of R and A. Such artifactual dissociations were obtained in a series of word-stem completion experiments: R increased with presentation duration, whereas A, paradoxically, decreased. Direct evidence for nonindependence was obtained from correlations between R and A in each of the experiments. These results suggest that the independence assumption was violated, and other applications of process dissociation should not be taken at face value without a thorough evaluation of independence.

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We investigated judgments of the frequency of test items (Y) that were highly similar to studied items (X) to test a prediction made by several memory models: that the judged frequency of Y should be proportional to the judged frequency of X. Whether stimuli were pictures or words, judged frequency of Y was bimodally distributed with 1 mode at zero, suggesting that frequency judgments involve a 2-stage process in which a zero judgment is made if there is a mismatch between retrieved information and the test item. Nonzero judgements, taken by themselves, were consistent with the prediction of proportionality. In 2 experiments, the percentage of zero judgments made to Y increased with repetition of X, but in 2 others the percentage did not change beyond frequency = 1. The percentage of "new" judgments in recognition memory followed this same pattern. Because the judged frequency of X increased even as X-Y discrimination showed no improvement, we characterize the result as "registration without learning."

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