Recognizing identical versus similar categorically related common objects:Further evidence for degraded gist representations in amnesia

Studies have shown lower false recognition of semantically related lure wor ds in patients with global amnesia than in matched controls. This pattern h as been interpreted as suggesting that medial temporal and diencephalic str uctures that are damaged in amnesia and that contribute to veridical memory also contribute to false recognition. It has been argued that whereas cont rols form and retain a well-organized representation of the semantic gist o f studied items, patients with amnesia can retain only a degraded gist repr esentation. However, these studies are subject to an alternative interpreta tion involving greater source confusions in controls. The authors used a ca tegorized-pictures paradigm to test recognition under conditions in which s ource confusions were unlikely to occur. Relative to controls, patients wit h amnesia showed reduced false recognition of categorically related pictori al lures, thereby supporting the notion of degraded gist representations in amnesia.