Maria S. Zaragoza

Misleading Postevent Information and Memory for Events. Arguments and Evidence Against Memory Impairment Hypotheses

The claim that a persons memory for an event may be altered by information encountered after the event has been influential in shaping current conceptions of memory. The basis for the claim is a series of studies showing that subjects who are given false or misleading information about a previously witnessed event perform more poorly on tests of memory for the event than subjects who are not misled. In this article we argue that the available evidence does not imply that misleading postevent information impairs memory for the original event, because the procedure used in previous studies is inappropriate for assessing effects of misleading information on memory. We then introduce a more appropriate procedure and report six experiments using this procedure. We conclude from the results that misleading postevent information has no effect on memory for the original event. We then review several recent studies that seem to contradict this conclusion, showing that the studies do not pose problems for our position. Finally, we discuss the implications of our conclusions for broader issues concerning memory.

Repeated Exposure to Suggestion and the Creation of False Memories

The purpose of the present study was to extend research on repetition and illusory truth to the domain of eyewitness suggestibility Specifically, we assessed whether repeated exposure to suggestion, relative to a single exposure, facilitates the creation of false memory for suggested events After viewing a video of a burglary, subjects were asked questions containing misleading suggestions, some of which were repeated Their memory for the source of the suggestions was tested The results show that following repeated (relative to a single) exposure to suggestion, subjects were more likely to (a) claim with high confidence that they remembered the suggested events from the video (Experiment 1) and (b) claim that they consciously recollected witnessing the suggested events (Experiment 2) The effects of repeated exposure were highly reliable and were observed over retention intervals as long as 1 week

Memory, Suggestibility, and Eyewitness Testimony in Children and Adults

Eyewitness’s ability to accurately perceive, remember, and report witnessed events has received a great deal of attention from experimental psychologists over the last decade (Bekerian & Bowers, 1983; Christiaansen & Ochalek, 1983; Christiaansen, Sweeney, & Ochalek, 1983; Clifford & Hollin, 1981; Loftus 1975, 1977, 1978, 1979a, 1979b; Loftus, Miller, & Burns, 1978; Loftus & Zanni, 1975; McCloskey & Zaragoza, 1985; Weinberg, Wadsworth, & Baron, 1983; Yarmey, 1979). While we have learned much about eyewitness testimony in adults as a consequence, there has been relatively little parallel work on the reliability of eyewitness testimony in children. Nevertheless there is a critical need for up-to-date research on the reliability of children’s testimony. Attempts to prosecute cases of physical or sexual abuse, in which the child involved may be the only witness, have brought to the fore issues pertaining to the accuracy and reliability of their testimony (Melton, 1981). Laws for dealing with child witnesses are currently in transition, and the courts are turning to social scientists for information and advice (see Goodman, 1984, for an extensive review of past and present laws concerning child witnesses).

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 McCloskey and Zaragoza (1985a) finding that misleading information did not affect subjects ability to recognize original information, argue strongly against the memory impairment hypothesis.

Intended and unintended effects of explicit warnings on eyewitness suggestibility: Evidence from source identification tests

Previous studies have shown that source identification (ID) tests reduce, and in some cases eliminate, eyewitness suggestibility errors. The present study showed that the suggestibility errors participants committed on a source ID test were further reduced when they were given the explicit postwarning that the experimenter was trying to trick them. These postwarnings reduced suggestibility to the same extent as prewarnings, and they did so for both once and repeatedly suggested items. In addition, the benefits of the pre- and postwarnings persisted when participants were retested 1 week later, but only if the suggestions had been repeated. For once-suggested items, the warning had the unintended effect of improving old/new recognition of the suggested information at retest, an effect that offset the improvements in source discrimination accuracy conferred by the warning. The advantages of using source ID tests for investigating group differences in eyewitness suggestibility are discussed.

Misinformation effects and the suggestibility of eyewitness memory

Social scientists and legal practitioners have long suspected that suggestive forensic interview practices are a major cause of inaccuracies in eyewitness testimony. However, it wasn’t until Elizabeth Loftus published a highly influential series of studies on eyewitness suggestibility in the 1970s that a systematic body of scientific literature on this topic started to emerge. Since then, hundreds of empirical studies on eyewitness suggestibility have been published, all of them variants of the basic experimental paradigm that Loftus developed. In the early 1970s, research and theorizing about memory was based almost exclusively on studies of memory for lists of words or sentences (see, e.g., Crowder, 1976). By studying memory for complex, fast-moving, and forensically relevant events (typically depicted in film clips or slide shows), Loftus demonstrated that it was possible to conduct well-controlled experiments that were high in ecological validity (Banaji & Crowder, 1989). Her studies provided clear evidence that suggestive interviews can lead to profound errors in eyewitness testimony, thus raising serious questions about the reliability of memory and eyewitness testimony. Her work established that scientific research on memory and suggestibility can and should inform the courts. In addition, her findings inspired many theoretical

Inoculation or Antidote? The Effects of Cognitive Interview Timing on False Memory for Forcibly Fabricated Events

This study examined whether a cognitive interview (CI) can counteract the effects of suggestive interviews involving forced fabrication. College students witnessed a filmed event and were later forced to fabricate answers to misleading questions about the event. All witnesses were interviewed with a non-leading CI or free recall (FR) either before or after the forced fabrication phase. A week later participants completed a recognition and source monitoring (SM) test of video content. Relative to FR, the CI administered before the forced fabrication interview increased reports of correct details and reduced false assents to fabricated items. A CI after resulted in false memory rates comparable to the FR group. Early interviews using CI techniques may protect against memory loss and misinformation effects.

The Role of Memory Impairment in Children’s Suggestibility

A central issue in the study of children’s long-term retention is an understanding of children’s susceptibility to memory failures. It has long been recognized that an important cause of memory failures is interference caused by new learning. Recently, interest in memory failures caused by subsequent learning has been revived in the context of studies on suggestibility and eyewitness memory. These studies have shown that, for subjects of all ages, exposure to misinformation (i.e., false information presented as truth) after viewing an event can lead to profound decrements in performance on later tests of memory for the originally seen event.

Inventing stories: Forcing witnesses to fabricate entire fictitious events leads to freely reported false memories

Studies of the forced fabrication effect have shown that participant witnesses are prone to developing false memories for specific items or details that they have been forced to fabricate earlier (e.g., what type of hat someone wore). Building on these earlier findings, the present study assessed whether participants would develop false memories if forced to fabricate entire fictitious events that were more complex and extended in time and involved people, locations, and actions that they had never seen. Participants vehemently resisted fabricating these events, and false memory development over the short term (1-week recognition test) was limited. However, after 8 weeks, participants freely reported their forced fabrications nearly 50% of the time and did so even when they had correctly and publicly rejected them earlier on the 1-week recognition test. This is the first evidence that participant witnesses will freely incorporate into their eyewitness accounts entire fictitious events that they have earlier been forced to fabricate.

The recollective experience of cross-modality confusion errors

There are at least two qualitatively different types of subjective experience that can accompany accurate recognition memory. Sometimes recognition is accompanied by conscious recollection of the learning episode (i.e., it isremembered), and in other cases it is not (i.e., it is simplyknown that the item is old). In the present study, we assessed the subjective experience that accompanies crossmodality confusion errors (misidentifying words as pictures) by measuring the extent to which subjects claimed toremember versusknow that the item was presented as a picture. The results of two experiments demonstrate that cross-modality confusion errors are often accompanied by conscious recollection, although not to the same extent as accurate memories. The findings also show that there is considerable overlap in the recollective experience that accompanies accurate and erroneous memories. Finally, the results support the contention that recollective experience cannot be directly inferred from test performance.