Academic journal article Memory & Cognition

Forced Confabulation Affects Memory Sensitivity as Well as Response Bias

Academic journal article Memory & Cognition

Forced Confabulation Affects Memory Sensitivity as Well as Response Bias

Article excerpt

Published online: 23 July 2011

© Psychonomic Society, Inc. 2011

Abstract A signal detection analysis assessed the extent to which forced confabulation results from a change in memory sensitivity (d^sub a^), as well as response criterion (β). After viewing a crime video, participants answered 14 answerable and 6 unanswerable questions. Those in the voluntary guess condition had a "don't know" response option; those in the forced guess condition did not. One week later, the same questions were answered using a recognition memory test that included each participant's initial responses. As was predicted, on both answerable and unanswerable questions, participants in the forced guess condition had significantly lower response criteria than did those who voluntarily guessed. Furthermore, on both answerable and unanswerable questions, d^sub a^ scores were also significantly lower in the forced than in the voluntary guess condition. Thus, the forced confabulation effect is a real memory effect above and beyond the effects of response bias; forcing eyewitnesses to guess or speculate can actually change their memory.

Keywords Forced confabulation . Memory suggestibility . Eyewitness memory . False memory . Memory

The majority of jurors and judges consider eyewitness identification to be the most persuasive type of evidence administered in criminal cases (Wells & Olson, 2003). However, the forensic research on postconviction DNA exonerations has revealed that approximately 75% of these cases involve eyewitness misidentifications (http://www. innocenceproject.org/understand/Eyewitness-Misidentifica tion.php). Although these recent DNA exoneration cases are compelling, the fallibility of eyewitness memory is not a new subject among psychologists (Munsterberg, 1908).

It is well established that exposure to postevent suggestion following an observed event can affect eyewitness memory for the event (e.g., Loftus, 1975; Loftus, Miller, & Burns, 1978; Pezdek, 1977). This is referred to as suggestibility, or the misinformation effect. In a typical suggestibility study, participants observe an event as a slide sequence, video, or film. Participants in the misled condition are asked questions exposing them to misleading information related to the event; participants in the control condition are not exposed to the misleading information. On a subsequent recognition memory test for the observed event, participants' false alarm rate to the misleading information is higher in the misled than in the control condition. Similarly, an intervening photographic lineup presented after an eyewitness has viewed an event suggestively decreases eyewitness identification accuracy on a subsequent lineup whether the eyewitness actually selects the innocent suspect in the initial lineup or not (Hinz & Pezdek, 2001; Pezdek & Blandon-Gitlin, 2005). Together, these findings demonstrate that one source of eyewitness error is postevent suggestion.

Despite growing empirical knowledge concerning eyewitness memory and improvements in practices within the law enforcement community, there are still a number of dubious interview procedures that may suggestively influence eyewitness memory. For example, if an interviewer believes an eyewitness observed an event, the interviewer may press the eyewitness for information he or she admittedly cannot remember. In such interview situations, law enforcement officials are likely to encourage eyewitnesses to "just guess" or speculate about the answer to a question. In so doing, the interviewer might induce the eyewitness to self-generate misinformation. Although research has demonstrated that misleading questions and other types of postevent suggestion may introduce false information into memory, less is known about the influence of self-generated information.

In several studies, it has been reported that event memory can be suggestively influenced by forcing individuals to recall or speculate about answers to questions even if they are unsure of the correct answer (Ackil & Zaragoza, 1998; Hastie, Landsman, & Loftus, 1978; Roediger, Wheeler, & Rajaram, 1993; Schreiber, Wentura, & Bilsky, 2001; Zaragoza, Payment, Ackil, Drivdahl, & Beck, 2001). …

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