Implicit false memory in the DRM paradigm: effects of amnesia, encoding instructions, and encoding duration

Recent studies with the Deese/Roediger-McDermott (Deese 1959; Roediger & McDermott, 1995) paradigm have revealed that amnesic patients do not only show impaired veridical memory, but also diminished false memory for semantically related lure words. Due to the typically used explicit retrieval instructions, however, this finding may reflect problems at encoding, at recollection, or both. Therefore, the present experiments examined implicit as well as explicit false memory in patients suffering from Korsakoff's syndrome and controls. In Experiment 1, encoding instructions either focused on remembering individual list words, or on discovering semantic relationships among the words. In Experiment 2, different presentation durations were used. Results emphasize the distinction between automatic and intentional retrieval: Korsakoff patients' veridical and false memory scores were diminished when explicit recollection was required, but not when memory was tested implicitly. Encoding manipulations only significantly affected veridical memory: Priming was reduced with thematic encoding, and explicit retrieval was facilitated when given more study time.