Legal Evidence or Distorted Memory: Addressing the Issue of Eyewitness Misidentification

A phenomenon known as misattribution of memory is known to cause errors in attributing sources to memories. According to Schacter (2001),[1] memory misattribution occurs when correct memories are attributed to the wrong source. For example, one may think of an idea as original, when in reality, he or she heard about it from another source: misattribution can often cause unintentional plagiarism.[2]

Donald Thomson, an Australian psychologist who was wrongfully accused of raping a woman, demonstrates a dramatic example of this phenomenon. However, it turned out that the woman was attacked by another man while she was watching a TV interview by Thomson (which quite ironically was about memory and memory distortion). This was a classic case of misattribution, in which one had a correct memory (Thomson matched the woman’s description of the rapist) but attributed it to the wrong source. 

Thomson, thanks to his alibi (he was on live TV at the time of the rape), was quickly cleared of all charges. In other cases, however, errors in eyewitness identifications can lead to judicial errors that take much more time to be resolved. In fact, memory misattribution is one of the many factors that affect eyewitness (mis)identifications.  

In February of 1982, Calvin Willis was convicted of rape and sentenced to life in prison without parole for a rape he did not commit.[3] In Willis’s case, a series of inconsistencies in the victims’ statements (with age ranging from seven to ten years old), identifications, and police testimony led to the wrongful conviction. For instance, whereas one police report said that the ten-year-old victim was unable to identify the attacker, another police report, which was not introduced at trial, said she identified Calvin Willis who lived in the neighborhood, and who, according to the victims’ mother, had been in their house before.[4] While the victim knew for a fact that she was raped, she attributed the memory to the wrong source, demonstrating a classical example of misattribution. Just 21 years later, after the Innocence Project accepted the case and sent evidence to the Forensic Science Associates for DNA testing, Willis was released from the Louisiana State Penitentiary in Angola in 2003. 

According to the Innocence Project, “mistaken eyewitness identifications contributed to approximately 71% of the more than 360 wrongful convictions in the United States overturned by post-conviction DNA evidence.” However, in the United States, the legal system currently allows conviction based on the testimony of a single eyewitness.[5] Based on the fallibility of memory as evidenced by the cases of Thomson and Willis, and keeping in mind that we can only know about the cases in which the alleged perpetrator was eventually exonerated, we must ask ourselves how the judicial system can balance the fallibility of memory with the importance of eyewitness testimonies in investigations. Indeed, eyewitness statements are historically the most convincing pieces of evidence in trials.[6]

However, many factors can contribute to memory distortions. Among them are memory misattribution and memory conformity.[7] The latter is a phenomenon by which individual memories are distorted when co-witnesses discuss the event. For instance, Timothy McVeigh was arrested after the Oklahoma bombing incident in 1995. When investigators asked three witnesses who worked at the shop where McVeigh rented the truck used for the bombing if he had an accomplice, only one of them confirmed it. However, all of them were able to provide details for an accomplice later. It turns out that the three witnesses had discussed their memories before being questioned and had thus influenced their recalls.[8]

Happily, research has shown that the legal system can contribute to reduce eyewitness misidentifications. Instead of displaying all suspects’ faces to witnesses in a simultaneous lineup, and thus relying on relative judgements, one can ask witnesses to make a “thumbs-up or thumbs-down” decision by showing faces of potential suspects in a sequential order, only exposing the witness to one face at a time.[9] Some researchers even argue that eyewitness memory is reliable if it is not contaminated (e.g. the memory was not influenced by discussion with co-witnesses) and proper testing methods are used, just like DNA evidence.[10] Such instructions for the legal system have been published: for example, in 2015, the National Research Council of the National Academies published a series of guidelines to provide instructions for eyewitness identifications. For instance, it recommends the documentation of the witness’ level of confidence when he or she first identifies a suspect.[11] It therefore remains for the legal system to ensure that proper methods are used to avoid contamination and distortion of eyewitness testimonies and educate jurors so that they are aware of the risks of potential unreliable testimonies. 

[1] Daniel L. Schacter, The Seven Sins of Memory: How the Mind Forgets and Remembers, Houghton Mifflin Company (Boston, New York), 2001.

[2] “Seven Common Memory Problems,” Harvard Health Publishing, Harvard Medical School, November 2011, https://www.health.harvard.edu/newsletter_article/seven-common-memory-problems.

[3] “Calvin Willis,” Innocence Project, March 19, 2020, https://www.innocenceproject.org/cases/calvin-willis/.

[4] Mark L. Howe and Lauren M Knott, “The Fallibility of Memory in Judicial Processes: Lessons from the Past and Their Modern Consequences,” in Memory (Hove, England), Routledge, July 4, 2015, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4409058/#cit0049.

[5] Davis, Deborah, and Elizabeth F. Loftus, “The dangers of eyewitnesses for the innocent: Learning from the past and projecting into the age of social media,” New England Law Review, 2012.

[6] Tanja Rapus Benton, David F. Ross, Emily Bradshaw, W. Neil Thomas, and Gregory S. Bradshaw, “Eyewitness Memory Is Still Not Common Sense: Comparing Jurors, Judges and Law Enforcement to Eyewitness Experts,” Wiley Online Library, John Wiley & Sons, Ltd., November 1, 2005.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/acp.1171.

[7] Chris French, “False Memories of Sexual Abuse Lead to Terrible Miscarriages of Justice,” The Guardian, Guardian News and Media, November 25, 2010, https://www.theguardian.com/science/2010/nov/24/false-memories-abuse-convict-innocent.

[8] Fiona Gabbert, Amina Memon, and Kevin Allan, “(PDF) Memory Conformity: Can Eyewitnesses Influence Each Others Memories for an Event” July 2003, https://www.researchgate.net/publication/39064700_Memory_Conformity_Can_Eyewitnesses_Influence_Each_Others_Memories_for_an_Event.

[9] Schacter, The Seven Sins, 97.

[10] John T. Wixted, Laura Mickes, and Ronald P. Fisher, “Rethinking the Reliability of Eyewitness Memory,” SAGE Journals, May 2, 2018, https://journals.sagepub.com/doi/10.1177/1745691617734878.

[11] National Research Council, “Identifying the Culprit: Assessing Eyewitness Identification” The National Academies Press (Washington, D.C., 2014).