kind of double dissociation ought to occur--it should be possible to find patients who fail to show implicit memory for words, sentences, and other kinds of declarative information (i.e., priming effects) but have normal explicit memory for that information. Such a pattern of performance would occur if the output of a particular memory module were disconnected from verbal/motor response systems, but the route from that module to CAS remained intact (see Fig. 18.1). As far as I know, no results of this kind have been reported. It has been documented that some Alzheimer patients do not show priming effects ( Shimamura et al., 1987), but these patients also have deficits in explicit remembering; their priming failure likely reflects a degradation of cortical representations rather than a disconnection ( Shimamura et al., 1987). The idea that it ought to be possible to find patients who show explicit but not implicit memory for declarative information represents a novel prediction of DICE, and could lead to empirical discoveries that might not otherwise have been made.
If the foregoing predictions are not confirmed, there would be grounds for rejecting the basic tenets of DICE. In so doing, however, valuable clues could be provided concerning the nature of the relation between memory and consciousness.
This chapter was supported by a Special Research Program Grant from the Connaught Fund, University of Toronto, by Grant No. U0361 from the Natural Sciences and Engineering Research Council of Canada, and by a Biomedical Research Support Grant from the University of Arizona. I am grateful to Laird Cermak, Peter Graf, Larry Jacoby, John Kihlstrom, Bob Lockhart, Mary Pat McAndrews, Susan McGlynn, Morris Moscovitch, Lynn Nadel, Roddy Roediger, and Endel Tulving for helpful comments and discussion concerning many of the ideas presented in this chapter.
Allport D. A. ( 1979). Conscious and unconscious cognition: A computational metaphor for the mechanism of attention and integration. In L.-G. Nilsson (Ed.), Perspectives on memory research, (pp. 61-82). Hillsdale, NJ: Lawrence Erlbaum Associates.
Allport D. A., & Funnell E. ( 1981). Components of the mental lexicon. Philosophical Transactions of the Royal Society of London, B 295, 397-410.
Amyes E. W., & Nielsen J. M. ( 1955). Clinicopathologic study of vascular lesions of the anterior cingulate region. Bulletin of the Los Angeles Neurological Society, 20, 112-130.
Anderson J. R. ( 1976). Language, memory, and thought. Hillsdale, NJ: Lawrence Erlbaum Associates.
Andrewsky E. L., & Seron X. ( 1975). Implicit processing of grammatical rules in a classical case of agrammatism. Cortex, 11, 379-390.