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(1998) The counting Stroop: an interference task 38 Lavie, N. and Cox, S. (1997) On the efficiency of visual selective specialized for functional neuroimaging – validation study with attention: efficient visual search leads to inefficient distractor functional MRI. Hum. Brain Mapp. 6, 270–282 rejection. Psychol. Sci. 8, 395–398 Escape from illusion: reducing false memories Chad S. Dodson, Wilma Koutstaal and Daniel L. Schacter Illusory memories are unsettling, but far from uncommon. Over the past several years, increasing experimental and theoretical attention has focused on misattribution errors that occur when some form of memory is present but attributed to an incorrect time, place or source. Demonstrations of errors and distortions in remembering raise a question with important theoretical and practical implications: how can memory misattributions be reduced or avoided? We consider evidence that documents the occurrence of illusory memories, particularly false recognition responses, and then review three ways in which memory distortion can be minimized. C.S. Dodson, Although memory is generally accurate, some illusions discovered that none of them remembered calling him. W. Koutstaal and and distortions in remembering are almost unavoidable. Trudeau now believes that he only imagined their concerns. D.L. Schacter are at People might accept illusory memories as true without In the course of examining this recollection more closely, he the Dept of Psychology, Harvard questioning them unless (or until) they encounter contra- eventually concluded that he was, in fact, out having a few University, 33 dictory evidence. Recalling his experience with the Vietnam beers that night. Kirkland Street, War draft, Garry Trudeau provides an example of the du- Memory distortions and illusions are troubling because Cambridge, 1 rability of false memories . Trudeau distinctly remembers they raise doubts about whether memory is a faithful mir- MA 02138, USA. calls of concern that he received from family and friends ror of the past. More practically, the prevalence and power when they learned of his draft number. He accepted the va- of memory distortions raise an important question: how tel: +1 617 495 3856 fax: +1 617 496 3122 lidity of this memory for several years until he spoke with can false memories be reduced or even eliminated? We will e-mail: cdodson@ those whom he believed had commiserated with him and first focus on two types of memory distortion, known as wjh.harvard.edu 1364-6613/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved. PII: S1364-6613(00)01534-5 391 Trends in Cognitive Sciences – Vol. 4, No. 10, October 2000 Review Dodson et al. – Reducing false memories false recall and false recognition, and will then consider studied earlier. Based on this experience, individuals might how these errors can be reduced by factors that operate pri- report that the new word is ‘old’. In addition, studying many marily at encoding, retrieval or both of these stages of related words might make it difficult to recollect the charac- memory. teristics of specific items that have been studied, thereby forc- ing participants to respond on the basis of overall familiarity Creating false memories or the general similarity of a lure item to the memory of the False memories occur when people believe that they have studied items8,9,18,19. However, it is important to emphasize experienced an item or event that is actually novel. A para- that false memories in the DRM paradigm are probably not digm that was developed initially by Deese and recently driven completely by overall familiarity or similarity. This is revived and modified by Roediger and McDermott, has because high levels of intrusion of the lure words are also ob- generated much experimental and theoretical interest served during free recall2–4 and, in recognition tests, partici- because it produces very high levels of false recall and pants frequently report that they ‘remember’ specific details false recognition2–4. In the Deese/Roediger–McDermott about having studied the lure word3,8. (DRM) paradigm, individuals study lists of words (e.g. a Although the preceding two explanations of the in- list might consist of tired, bed, awake, rest, dream, night, crease in the false recognition rate for related new words blanket, doze, slumber, snore, pillow, peace, yawn and are difficult to distinguish within the DRM paradigm, drowsy), where each word in a given list is related to a Koutstaal and Schacter20 have provided data that are con- non-presented or ‘lure’ word (e.g. sleep). On a subsequent sistent with the latter explanation. After studying large old–new recognition test that contains the studied words numbers of pictures from various categories (e.g. cars, (e.g. tired, dream) and new words that are either unrelated shoes, etc.), participants often falsely recognized new pic- (e.g. butter) or related (e.g. sleep) to the studied words, tures from the same categories as the studied pictures. participants often mistakenly report that they previously Koutstaal and Schacter20 reasoned that it is highly improb- studied the related new words, even claiming to ‘remem- able that participants had generated the new related pic- ber’ specific details about the items. In fact, the false tures in the same way that they might generate the word recognition rate of the related new words is so high that it ‘sleep’ when studying associated words in the DRM pro- is often equivalent to, or closely approaches, the correct cedure. Instead, they attributed the false recognition of new recognition rate for studied words5–9. pictures to the high degree of similarity among target items, Several recent investigations have begun to uncover the which produces robust memory for what the related items factors that contribute to this false memory effect. Several have in common but poor memory for specific items (also studies have shown that individuals are more likely to falsely see Ref. 21). recognize a related new word when they have studied many, These findings suggest that source confusion errors, rather than few, associates of the item beforehand10–13. For which involve a misattribution of internally generated instance, Arndt and Hirshman presented participants with events with actually presented events, do not necessarily lists that contained either four or 16 related words (list contribute to false recognition. However, such confusions lengths were equalized by including filler items)10. could still play a role in the DRM paradigm. Consistent Recognition rates for studied words increased slightly, from with this possibility is the observation that although college 58% for lists of four related words to 61% for lists of 16 re- students show very high levels of false recognition in the lated words. By contrast, the rate of false recognition of re- DRM paradigm, with the false recognition rate approaching lated new words rose sharply from 41% to 67% (Ref.