When misleading postevent information biases one's memory for an event, what is the fate of the original, accurate information? One possibility is that the new information and the original information coexist in memory, but that the former is simply more accessible. A second hypothesis suggests that the new information replaces the old, and memory is irreversibly altered. Using various retrieval techniques, Loftus and her associates (Greene, Flynn, & Loftus, 1982; Loftus, 1979a Loftus, , 1979b have failed repeatedly in attempts to recover original memories after postevent biasing, a finding that supports the alteration hypothesis. In the present study, postevent biasing was demonstrated in two experiments. In each experiment, some subjects were given a warning that the postevent information had included a few inaccurate details. These subjects were able to edit out the inaccurate details and to recover the original facts when the warning came as much as 45 min after they had read the misleading information, a result that argues for the coexistence of memories. Successful recovery of the original memories was apparently due to the clarity of the warning and to an improved technique for assessing the retrieval of original memories.In recent years, numerous studies have demonstrated that misleading postevent information introduced in a narrative or as a presupposition of a question can alter a person's recollection of an event (e.g., Christiaansen, Sweeney, & Ochalek, 1983;Dodd & Bradshaw, 1980;Loftus, 1975;Loftus & Greene, 1980; Loftus, Miller, & Bums, 1978;Loftus & Palmer, 1974;Powers, Andriks, & Loftus, 1979). Although it is clear that such postevent information has an effect, questions remain about why the false postevent information is remembered instead of the original, when it is demonstrated (or at least reasonably certain) that the original information was indeed encoded in memory. Perhaps the original information still exists in memory, but is simply less accessible than the more recent biasing information. Loftus (l979a) referred to such an explanation as the coexistence hypothesis, since the original and postevent information coexist in memory. Alternatively, one's memory could actually be changed and updated, and the original representation destroyed, each This research is based on an honors thesis by the second author under the supervision of the first. We wish to thank Audrey Skaife and the University of Wisconsin-Oshkosh for providing subjects for Experiment 2, andElizabeth F. Loftusfor providing copies of her event slides used in that same experiment and for additional materials used in constructing the narratives and tests. We also