This is the final post in a series about memories of eyewitness testimony. The first post described how memories are formed and remembered, while the second talked about how memories decay can be distorted and manipulated. This post will give some suggestions on how to increase the accuracy of information an eyewitness provides.
As we saw in the previous posts, our brains often “fills in the gaps” of parts of events in memories that we may be uncertain about. For instance, studies have shown that people are more likely to recall seeing broken glass after being asked whether a car “smashed” into another, rather than “contacted”, and John Dean clearly remembered being asked to take a seat by President Nixon in a meeting, when tape recordings showed this never happened. Additionally, external information can cause a misinformation effect by distorting a memory. For example, an eyewitness might see the events of a crime and store that information in memory, and then read in a newspaper article that another witness said the perpetrator was carrying a firearm. Even though the original witness didn’t perceive any weapon at the time of the events, that information may get implanted into their memory, without being consciously aware that this piece of misinformation did not come from their own experience.
In 2014, the National Academies released a report entitled “Identifying the Culprit: Assessing Eyewitness Identification” that detailed these same limitations with memory within the context of eyewitness testimony. Additionally, they listed several important procedures that improve the accuracy of memories from eyewitnesses and are based on decades of research in memory, perception, and eyewitness testimony.
very likely to identify the person that best fits their memory of the relevant individual – even if that person is not in the lineup. That is, the eyewitness is making a relative judgment (“this person looks most like who I remember out of everyone in the lineup”, rather than “this person looks like the person who I remember”). This is especially the case when the lineup is presented simultaneously, as the eyewitness can compare each member of the lineup to each other before coming to a decision.
Second, it is possible for lineups to be biased: imagine a case where the main suspect of a crime is a tall man with blond hair. If the lineup contains one man somewhat fitting this description and the remainder being short men with dark hair, it’s highly likely that the blond man is going to be picked out as he is the only member of the lineup that even somewhat resembles the description. Third, it is possible that those administering the lineup can consciously or unconsciously bias the eyewitness if there is a particular person they suspect is implicated. Lastly, in high-stress events like witnessing a crime, memory accuracy will also be affected and our brains will fill in the gaps to cover parts of the event that were not confidently remembered so that the memory is coherent, if not completely accurate. All in all, these practices only serve to distort memories, and therefore decrease the accuracy of eyewitness testimony and identification.
To counter the lack of awareness of how memory works, it is recommended that courts bring in experts to advise juries about the ways that eyewitness evidence can fail, such as in the ways that this and the previous posts discuss. The report also urges the use of “double-blind” lineups, where the police officer administering a lineup does not know who the relevant person is, leaving them unable to offer any conscious or unconscious biasing cues to the eyewitness. It recommends that police officers record a witness’s confidence level upon first identifying a suspect — a time when their assessment of their own confidence is more likely to be accurate, and when their memory is less likely to have been contaminated.
Since the National Academies’ report was released in 2014, at least 19 states have passed legislation or adopted rules requiring reforms recommended by the report, such as recording witnesses’ confidence levels and using double-blind lineup procedures. The federal government has also made changes to lineup procedures in federal cases – in 2017 the Department of Justice released new guidelines for how lineups using photographs should be conducted, based on procedures recommended in the report. Even prior to this, the International Association of Chiefs of Police issued a new model policy for conducting lineups, also drawing upon the report.
This series of blog posts has introduced some basic concepts of memory and explained how fragile it is as it can very easily be distorted and manipulated. It is a very personal and subjective recollection of an event and is certainly not perfect like an audio or visual recording. Additionally, entirely false memories can be implanted simply through the power of suggestion. However, through more rigorous and science-based procedures, eyewitness memories can be highly accurate, which can give police and jurors more confidence that an event really did occur as an eyewitness claims it did.
Frueh, S. (2020). Using Science to Improve Eyewitness Testimony. https://www.nationalacademies.org/news/2020/01/using-science-to-improve-eyewitness-testimony