Processing implicit and explicit representations.

Abstract

This article summarizes the results of a 15-year research program dedicated to understanding how implicitly activated memories affect remembering and proposes a model for describing such influences. Implicit memories are manipulated by varying the number of associates preexperimentally linked to test cues or to studied words. Assumptions of the model specify when implicit memories of various types are likely to contribute to performance in various tasks. The main assumptions are that encoding involves both explicit and implicit processing components and that these components provide mutually exclusive sources of information during testing. Experiments designed to evaluate the exclusivity assumption are reported, and implications of the findings for several theoretical frameworks are discussed.

Effects of target set sizeon feelings of knowing and cued recall: Implications for the cue effectiveness andpartial-retrieval hypotheses

“…In recall, response times (RTs) always were much faster for cues linked to smaller sets than for those linked to larger sets. This finding was consistent with prior work suggesting that people sample competing items that are related to the test cue and that, with fewer competing items, the probability of sampling the target is higher and the time needed to retrieve it is faster than with a greater number ofcompeting items (D. L. Nelson, Gee, & Schreiber, 1992; D. L. Nelson, McEvoy, & Bajo, 1988; D. L. Nelson, Schreiber, & McEvoy, 1992). A different pattern ofRTs was found for FOK ratings.…”

Associative memory in chronic schizophrenia: a computational model

“…These two dimensions had considerable appeal and relevance, providing an empirical means to elucidate the dynamics of associative memory and, by extension, associative disturbance in schizophrenia. The connectionist computational model incorporated each of these dimensions in order to provide a direct test of the pattern of findings discussed by Nelson et al (1992) and the abnormal associative connectivity effect seen in the prior behavioral studies of associative memory in patients with chronic schizophrenia. In addition, the computer-generated model also tested directly the extent, if any, to which random "neural" noise might account for the abnormal schizophrenic pattern of recall observed in the prior behavioral study.…”

Cognitive dysfunction in schizophrenia: unifying basic research and clinical aspects

“…Likewise, words differ in associative strength, as reflected by the degree of connectivity of a word and its associates, and/or the degree of connectivity among its associates. Thus, connectionist models provide the tools to test whether schizophrenic associative disturbance reflects a failure of connectivity and/or network size to modulate activation within the lexicon (Nelson et al 1992 and. In so-called "PDP neural models", the connectivity may be viewed as related to idealized synaptic weights and the network size to the number of idealized neurons activated.…”

“…Nestor et al (1998) used a cued-recall word paradigm and norms derived from Nelson to attempt to identify the cognitive dynamics underlying schizophrenic associative disturbance. Schizophrenic patients and comparison subjects studied a list of to-be-remembered target words, and then were given a cued recall test in which both word targets and cues were equal in terms of connectivity and network size, as measured by the quantitative normative studies of Nelson et al (1992Nelson et al ( , 1993. These studies used the number of associates of a word to determine its network size and the degree of association both among these associates and between the target word and its associates to determine its network connectivity.…”