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Abstract:
Abstract: Individuals sometimes incorrectly claim to have
experienced novel events or stimuli that, in fact, were not
previously encountered. Using a paradigm involving multiple
semantically related words, all of which converge upon a single
(nonpresented) lure word, several studies have shown lower levels
of such "false recognition" errors in amnesic patients than in
matched controls. This pattern has been interpreted as suggesting
that the medial-temporal and diencephalic structures that are
damaged in amnesia, and that contribute to veridical memory, also
contribute to false recognition. It has been argued that whereas
controls form and retain a strong and well-organized representation
of the semantic "gist" of the studied items, amnesics are able to
retain only a relatively degraded gist representation. However,
these studies are subject to an alternative interpretation
involving a heightened likelihood of source confusions in control
participants. We used a categorized pictures paradigm to explore
false recognition in amnesics under conditions where source
confusions are unlikely to occur. Relative to matched controls,
amnesics showed decreased false recognition of
categorically-related lures that were conceptually and perceptually
similar to many studied items (Experiments 1 and 2); further, the
magnitude of the group difference was increased under conditions
that made it difficult for matched controls to extract
item-specific information (Experiment 2). These experiments support
the notion of degraded gist-representations in amnesia.
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