Introduction:memory expert_01.13.15

In the United States, eye witness and “memory” or recall testimony by lay witnesses can be challenged by expert testimony in criminal cases in 45 of the 50 states’ courts. However, recent studies have demonstrated that challenging lay witnesses who are relying on their memory of an event should not be limited to the criminal sphere. Moreover, these studies proclaim the absolute necessity to have expert witnesses involved to challenge lay witness memory testimony and further demonstrate how erroneous that lay testimony may be, as well as the mistaken assumptions of most jurors, absent in an expert’s intervention. This article provides a general overview of the issues pertaining to memory testimony and an explanation of why the experts are so vital to any such testimony by lay witnesses.


There are many interesting aspects to the concept of involving expert witnesses on memory in civil cases where eye or memory lay witnesses offer testimony. One study of a fairly general nature demonstrates how much conventional wisdom (and most juror’s instincts) is at odds with the scientific realities of how accurate an individual’s memory actually is. This study and its conclusions will be discussed to demonstrate the vital importance of expert testimony in civil cases involving memory witnesses.

Daniel J. Simons, a professor from the Department of Psychology at the University of Illinois, joined his colleague, Christopher F. Chabris, co-director of the Neuroscience program and professor of psychology at Union College, in organizing a study to test commonly-held beliefs on how memory works, versus the knowledge of memory experts with ten or more years of experience, specifically discussing the American legal system and juries in their study. See Simons, D.J., & Chablis, C.F., “What People Believe about How Memory Works: A Representative Survey of the U.S. Population,” PLOS ONE, Aug. 3, 2011. The authors contend that the vast difference between popular beliefs about how memory works and the scientific realities are so serious as to have major implications in the courtroom. Id.

There are two particular problems with the fact that the authors (among others) found such a discrepancy. First, if lay witnesses are to rely on their memory of an event, but their beliefs about such an event become distorted because of a misunderstanding of how the human brain works in the context of memory, that testimony is flawed and may lead to unjust results in any court. Second, the fact that most jurors identify with the same erroneous beliefs as lay witnesses makes injustice even more likely because most jurors will believe that the witnesses’ testimony about their memories are accurate, and therefore dependable. As the authors note, when there is a significant divergence between popular beliefs about memory and what science actually knows to be the case, “memory experts will have an important role in educating judges, juries, lawyers, and the public about the properties of memory.” Id. Moreover, the authors note that “jury pool members underestimated the influence of factors known to affect eyewitness accuracy, including the status of the person providing post-event suggestions, the age of the witness, the delay between the original event and recall, and the impact of providing warnings about potentially misleading suggestions.” Id. The jurors were found to have the same misconceptions about how memory works as the general population, which did not coincide with the expert’s view of memory, on which the authors’ experts reached a consensus. Id. The interviewed experts, who had reached a scientific consensus, were selected at the 2010 meeting of the Psychonomic Society, an organization with over 50 years of experience in studying how the human mind works. All of the 73 experts interviewed had over 10 years of memory research experience. As the authors discovered, over 60% of the non-expert respondents they interviewed agreed with statements about memory and recall that every single expert rejected as false. Id.

One issue, which 63% of lay respondents agreed with, was that memory operates like a video camera, where it is possible to save a memory, as well as “rewind” and “replay” that memory, exactly as it happened at the time of an event. Id. The problem with this belief is that it is patently false from a scientific viewpoint and contravenes the well-established principle that retrieving a memory is a process that is not static and is heavily influenced by knowledge, beliefs and prejudices, and expectations. See id. As the authors explain: “This belief is perhaps the most relevant to the role of expert testimony on memory in legal cases. If jurors believe that memory works like a video camera, they will be more likely to trust witnesses who saw an event without realizing that different people may encode the same event differently or that memory can be distorted by subsequent events.” Id.

Another issue the authors uncovered dealt with the issue of permanent memory, as a substantial portion of the lay respondents claimed that once an event is experienced and a memory is formed of that event, that memory never changes. See id. The problem, again, is that even if a memory is permanent in its basic contours, it can be strengthened, weakened, or changed by later experiences. Id. If lay witnesses are unable or unwilling to admit that their memories of events have not changed, particularly over a period of time, this poses a problem with their testimony. If left unchallenged by a memory expert, such as a psychologist or psychiatrist, that problem in testimony is likely to go unnoticed by a judge and even more likely to be overlooked by a jury of individuals, who generally believe in the same principles as the lay witness does regarding memory. In a situation where lay witnesses, though not intentionally, magnified or distorted their testimony because of a distortion of their memories, serious miscarriages of justice would occur if a judge or jury took that testimony at face value, not accounting for human fallibility in giving memory evidence.


As the authors expressed, every belief that they documented in their study “runs counter to expert scientific consensus and reflects a fundamental misunderstanding of the way that memory works.” Id. Most of the scientific principles that were established in the study about memory had been proven for decades. The authors concluded: “The prevalence of mistaken beliefs in the general public implies that similar misunderstandings likely are common among jurors and could well lead to flawed analyses of testimony that involves memory. …Expert testimony on these issues could well help overcome such misinterpretations…,and at a minimum, it could make jurors aware of some of the limitations of memory.” Id. This and many similar studies demonstrate that attorneys should retain psychology or psychiatry experts in memory to challenge lay testimony; moreover, such experts are critical to achieving justice in civil litigation.