Memory and the Law

Chapter Overview:

Chapter 11 focuses on eyewitness testimony and its vulnerability to distortion as well as the impact that the nature of memory has in the legal system.

While concerns about eyewitness testimony have been noticed as early as 1908, it was not until the early 1970s that modern psychology methodically tested the memories in eyewitnesses. In the classic work by Elizabeth Loftus and colleagues, participants viewed films of accidents and were then asked several questions that included some misleading information. The misleading post-event information was shown to distort and change the memory of the event (called the misinformation effect). Some researchers believed that the original memory stayed intact but was accompanied by a modified representation as well. Recent research however supports the notion that we have one representation of an event and that this memory can be modified with new, possibly erroneous information. This finding is important as it helps explain why witnesses can consistently and confidently report incorrect information about an event.

Loftus and colleagues took this line of research a step further and investigated whether it was possible to implant a memory for an entire event that had not occurred. Using the “lost in the mall” technique, researchers were able to demonstrate that people were in fact able to develop ‘memories’ of events that had not occurred. Related research also revealed that a 30-minute therapy session using dream analysis was sufficient to produce false memories of being lost in a public place as a child.

In the 1990s, the very emotional and bitter “memory war” was in full swing. Memory researchers argued that memory is fallible, and recollections could be distorted or even totally false while therapists and survivors of childhood abuse claimed that traumatic memories were fundamentally different and could be totally repressed and then recovered through therapy and hypnosis. However, while substantial evidence exists supporting that people could have false memories of abuse, there is no evidence that repression of traumatic events is different than normal forgetting and little to no evidence supporting the notion of repressed memories being recovered in therapy.

The same process that produces false memories may also help explain false confessions (when a person takes responsibility for a crime they did not commit). The suspect may begin to encode memories of themselves committing the crime after repeated presentations of often plausible scenarios. By imagining themselves doing the crime, a suspect may eventually start to believe that the imagined event is real (called imagination inflation) and eventually believe that they did in fact commit the crime. Recommendations have been made to help reduce the likelihood of false confessions.

Once a suspect is in custody, an eyewitness will often have to identify him or her. Two procedures exist: showups and lineups. In showups, the witness is shown an image of the suspect and asked if this is the person that committed the crime. In lineups, the eyewitness must identify the suspect from a number of similar-looking people called fillers. Research suggest that the showups are problematic because the eyewitness can easily replace the image of the real perpetrator with the image in the picture in their memory. If they are unsure about the photo, they may still make a positive identification if they believe that the police truly caught the real suspect or there is any pressure from the police to say yes. Unbiased lineup procedures seem to provide better results. To reduce the bias, it is important to ensure all fillers match the description of the suspect, that the suspect’s photo does not differ in any way from the fillers, and that a double-blind procedure is used. An inclination to identify a suspect as guilty may also result from unconscious transference (when the suspect is familiar to the witness, that familiarity may lead to an identification).

Eyewitnesses are less accurate at identifying suspects of a different race. This phenomenon, known as the cross-race effect (CRE), was thought to be due to familiarly with the members of one’s own race. However, newer research has suggested that it might be more of an in-group bias. Specifically, members of in-groups receive more attention, leading to better encoding and therefore enhanced recall of facial features.

By factoring in the eyewitness’ confidence in the identification process, two new approaches have been developed that seem to be able to reduce some of the issues that lead to misidentification. In one procedure, witnesses are shown a photo of possible suspects and asked how confident they are that this was the culprit. High confidence judgements were strongly correlated with accuracy. In other research, when witnesses were given the option of “I don’t know” when asked to identify suspects the number of accurate responses increased.

Many memory factors can also influence jury decisions. Some court cases are discussed in the media prior to the trial and this pre-trial publicity (PTP) can impact both the memory of the jurors and the deliberation process. Research by Ruva and McEvoy in 2008 clearly found significant source memory errors and that negative PTP doubled the likelihood of getting a guilty verdict even when the participants were instructed to disregard it. In subsequent research, they found that negative PTP was included in the deliberations even when the jurors knew the information to be PTP. These findings strongly suggest that PTP can bias the jurors about the defendant.

Other jury factors can influence memory and decisions in a court of law. In trying to remember all the trial information, juries seem to construct a story that includes their personal experiences and inferences. These stories are used to decide guilt or innocence. Note-taking during a trial results in a significant increase in recall of trial-related information and therefore should be encouraged especially if jurors are required to remember a lot of information. Research also supports the notions that jurors remember emotional content, especially negative, better than non-emotional content. Also, there is a bias towards remembering material that was personally relevant. Memory gaps in jurors has historically been assumed to be improved through the deliberation process but new research has shown that while deliberation does improve memory slightly, juror confidence (and not accuracy) seems to be the dominant influence in the deliberations.

A controversial technique called brain fingerprinting uses electroencephalogram (EEG) activity to determine whether a suspect can have specific memories of a crime only the perpetrator would know. A P300-MERMER response occurs when a suspect is presented with this information. While brain fingerprinting has been used in actual cases, a number of strong concerns remain, including the fact that the claims have never been subjected to peer review research and that it is even less reliable than a standard polygraph. Other possibly more promising techniques are the use of skin conductivity and the cognitive interview.

Learning Objectives:

Having read this chapter, you will be able to do the following:

  1. Explain the misinformation effect and provide an example of an experiment that demonstrates this effect.
  2. Describe how experimenters were able to implant false memories and the implications this has for psychotherapy.
  3. Describe the different types of identification procedures.
  4. Discuss what social factors can lead to less reliable eyewitness identifications.
  5. Explain how an investigator may use confidence ratings to assess the accuracy of an eyewitness identification.
  6. Describe the memory war and its outcome.
  7. Explain how normal memory processes can lead a person to make a false confession.
  8. Explain how pre-trial publicity and note taking may influence jurors’ memories.
  9. Describe how emotional testimony influences jurors’ memories.
  10. Describe and critique brain fingerprinting.
  11. Identify memory theories that underlie the cognitive interview.
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