Memory loss versus memory distortion: The role of encoding and retrieval deficits in Korsakoff patients’ false memories

Abstract

Recent studies with the Deese/Roediger-McDermott (DRM) paradigm have revealed that Korsakoff patients show reduced levels of false recognition and different patterns of false recall compared to controls. The present experiment examined whether this could be attributed to an encoding deficit, or rather to problems with explicitly retrieving thematic information at test. In a variation on the DRM paradigm, both patients and controls were presented with associative as well as categorised word lists, with the order of recall and recognition tests manipulated between-subjects. The results point to an important role for the automatic/controlled retrieval distinction: Korsakoff patients’ false memory was only diminished compared to controls’ when automatic or short-term memory processes could not be used to fulfil the task at hand. Hence, the patients’ explicit retrieval deficit appears to be crucial in explaining past and present data. Results are discussed in terms of fuzzy-trace and activation-monitoring theories.

Keywords:

• Amnesia
• DRM paradigm
• Gist memory
• Explicit recollection
• Encoding deficit

Acknowledgements

The authors would like to thank the personnel of the psychiatric centre Sint-Amandus (Beernem) for coordinating the participation of their Korsakoff patients. Thanks to Evlin Smeets for running the experiment. Ilse Van Damme is a PhD Fellow of the Research Foundation-Flanders (FWO). Portions of this work were presented at the Annual Meeting of the Belgian Association for Psychological Sciences, Liege, Belgium (May 2006), at the 4th International Conference on Memory, Sydney, Australia (July 2006), and at the Joint Meeting of the Experimental Psychology Society and the Belgian Association for Psychological Sciences, Cardiff, UK (April 2007).