Misleading postevent information and recall of the original event: Further evidence against the memory impairment hypothesis

This study evaluates the hypothesis that misleading postevent information impairs memory for the original event. Subjects viewed a sequence of slides depicting an event, read a postevent narrative that presented neutral or misleading information about critical details, and then were tested on their ability to recall the critical details. In two experiments no difference in recall performance between misled and control conditions was found. These results, in conjunction with the The claim that misleading postevent information may impair memory for an event has gained considerable currency among memory researchers. The empirical basis for this claim is a substantial body of results obtained with a procedure we will call the original recognition test procedure. In a typical experiment subjects first view a sequence of slides depicting an event such as a traffic accident or robbery. Postevent information, such as a written narrative description of the event, is then presented. For subjects in the misled condition the narrative provides misleading information about a detail from the original event. For example, a can of Coke appearing in the slide sequence might be described in the narrative as a can of 7-Up. For subjects in the control condition the postevent narrative provides no specific information about the critical detail. After presentation of postevent information, memory for the original event is assessed with a two-alternative forced-choice recognition test. For the test question about the critical detail, the alternatives are the item from the original slide sequence (e.g., Coke), and the item presented to misled subjects as misleading postevent information (e.g., 7-Up). The consistent finding is that misled subjects perform more poorly than control subjects on the question about the critical detail (e.g., The memory impairment interpretation has been widely accepted, and attention has focused primarily on the nature of the presumed impairment. Some researchers (e.g., We thank Neal Cohen, Howard Egeth, and Judith McKenna for their helpful comments and Laura Bowman for her assistance in testing subjects. Correspondence concerning this article should be addressed to Maria S. Zaragoza, Department of Psychology, Kent State University, Kent, Ohio 44242. information to be lost from memory, whereas others (e.g., Bekerian & Bowers, 1983; Recently, however, Zaragoza (1985a, 1985b) called the memory impairment hypothesis into question, arguing that results obtained with the original recognition test procedure do not imply that misleading postevent information in any way affects memory for the original event. The original recognition test, they suggested, is not appropriate for assessing effects of misleading postevent information on memory; because of response biases inherent in the procedure, poorer misled than control performance is expected even if misleading information has no effect on memory for the original event. Thus, although studies using the original test procedure clearly demonstrate that misleading postevent information may influence subjects' responses to test questions, the studies fail to demonstrate that the misleading information affects subjects' ability to remember the original event. (See McCloskey & Zaragoza, 1985a, pp. 2-4, for a more detailed discussion of this point.) McCloskey and Zaragoza (1985a) used a modified recognition test procedure to obtain results bearing more directly on the memory impairment hypothesis. The modified procedure was the same as the original procedure except that the test question for the critical detail offered subjects a choice between the originally seen item (e.g., Coke) and a new item (e.g., Sunkist orange soda). With the modified procedure, poorer misled than control performance is expected if misleading information impairs memory for the original event. If, however, misleading information does not affect subjects* ability to remember the original event, no misled/control difference is expected. The results obtained with the modified procedure argued against the hypothesis that misleading postevent information impairs memory for the original event; in six experiments McCloskey and Zaragoza found no effect of misleading information. In this article we report another test of the memory impairment hypothesis. The McCloskey and Zaragoza (1985a) experi-3