Memory Errors for Everyday Events: Forensic Implications

Article excerpt


Confusions between imagery and memory are a serious forensic concern and although they have been demonstrated in several laboratory contexts, their frequency has not been examined for naturalistic circumstances. As such, we report two studies that examined the frequency of memory errors and confusions in everyday life through surveys and diaries. Errors were rated as quite infrequent, but occurred more often for memory-related errors (i.e., forgetting, switches in retrospective recall, and future plans) than for imagination-related errors (i.e., imagery, dreams, fiction). The diaries further indicated that imagery is frequently used for purposes such as planning, decision making, mental rehearsal, and imagining the experience of others. These findings suggest that memory errors and confusions occur primarily for familiar events that are consistent with events in a person's life, and seldom occur for unfamiliar experiences even when they are vividly imagined.

It is clear that the issue of memory is a very important one for policing. For example, police and other security service personnel rely heavily on the memories of victims and witnesses to solve crimes and aid in the prosecution of offenders. Unfortunately, research indicates that memory is not always reliable. For instance, memory mistakes can be caused by confusion between two different events or by misleading information. One particular concern is the effect that imagery has on memory accuracy. Although imagery can improve memory, misleading suggestions also lead to more memory errors when people imagine the suggested scenario (Hyman & Pentland, 1996). The effect of imagery on memory accuracy is thus not entirely clear, and police may have a difficult time knowing whether to trust memory that has been enhanced through the use of imagery techniques such as the cognitive interview (Geiselman, Fisher, MacKinnon, & Holland, 1986). Most research on this issue examines memory for dramatic events, such as staged crimes or spilling punch on a wedding guest. However, in order to increase our understanding of the effect of imagery on memory, the studies reported in this paper examined how often memory errors occur in everyday circumstances rather than dramatic events, with a particular focus on errors related to imagined experiences. It is argued that this knowledge is of interest to police and others due to the fact that some witnesses are asked to remember a criminal event that was not really dramatic but was simply part of their everyday experience. For example, someone shopping may be asked if they recognize an individual who was in the store at the time a crime such as shoplifting occurred. Memory researchers generally agree that memory is frequently in error and can easily be confused (e.g., Conway, 1996; Koriat, Goldsmith, & Pansky, 2000). There is ample evidence for this in the literature, including errors associated with misleading information (e.g., Ayers & Reder, 1998) and false memories generated under various conditions (e.g., Loftus & Pickerell, 1995; Roediger & McDermott, 1995). Experience, however, indicates that in everyday life we rely on our memory quite often and it generally serves us well, so it cannot be entirely erroneous. In legal settings this is not just an intellectual curiosity--serious decisions are based on the memories of witnesses, defendants, and accused individuals, not to mention the memories of jurors and legal teams. Thus, it is important to understand the balance between memory error and accuracy, as well as the factors that contribute to each.

Imagined experience has received particular attention as a potential cause of memory errors. Research indicates that vivid sensory and emotional characteristics associated with imagery can be confused with the characteristics that are typical of memories for actual events. Reports of imagery are often given for falsely attributed memories (Conway, 1996), and there is evidence that guided imagery may increase the risk of memory distortion and misattribution (Heaps & Nash, 2001; Hyman & Billings, 1998; Hyman & Pentland, 1996; Loftus, 1997; Shobe & Schooler, 2001; see Arbuthnott, Arbuthnott, & Rossiter, 2001 for a review). …