Introduction:Memory Testimony Pt II

The first article in this series focused on the general issues of lay memory testimony and the use of expert witnesses in assessing the quality of that evidence in civil cases. This article is more specific and centers on asbestos litigation, with a discussion of how eyewitness/memory testimony has proven itself to be quite fallible and the particular implications.


The problem with memory testimony in asbestos cases is highlighted by an American Psychology-Law Society (AP-LS) article published in 2013. See Charles A. Weaver, III, “Eyewitness Memory in Civil Litigation,” American Psychology-Law Society News, October 2013. Asbestos litigation is a form of product liability, which requires that witnesses recall “precisely which products they used, and when.” Id. Moreover, “‘the demands on witnesses’ memories are often more daunting in civil litigation, particularly those involving mesothelioma resulting from alleged asbestos exposure.” Id.

One of the biggest problems with relying on a lay witness’s memory is the amount of time that has passed between alleged exposure to asbestos and the time mesothelioma occurs. Mesothelioma often lies dormant for 20-50 years, which requires plaintiffs to remember what asbestos-containing products they used several decades ago.

Another issue of concern is that witnesses are required to recollect the kinds of products that they saw being used or used themselves, the names of the manufacturers of those products, and the specific brand names of those products. As the AP-LS notes: “Manufacturers often made several different versions of a product, not all of which contained asbestos.” Id. This makes it even more difficult to imagine a witness being able to correctly recall exactly which version of which product they were exposed to, and for that version to have been one which would have had asbestos in it.

Furthermore, witnesses in asbestos litigation are required to recall details about the products and events at issue, where the significance of such details was unlikely to be apparent when the product use occurred. See id. Because of the way memory functions, it is much less likely for a person’s memory to operate as well after a period of time (particularly a significant one) has elapsed than shortly after an event occurs. As one study found, “the motivation to remember is significantly more effective when that motivation occurs before (not after) an event is encoded.” Id., citing Kassam, Gilbert, et al., “Misconceptions of Memory: The Scooter-Libby effect,” Psychological Science, 2009.

A final problem with memory testimony in asbestos cases is that many plaintiffs are claiming secondary exposure: They are not arguing that they, themselves, worked directly with asbestos, but that a coworker did. In these cases, a witness would have to recall all of the information about the product that contained asbestos, even though it was never directly handled and the witness may only ever have had a glimpse of the product. See id.

To investigate the ability of lay witnesses to remember, with such precision, the necessary components of asbestos litigation, the AP-LS conducted experiments involving memory with product identification. They noted: “with longer retention intervals witnesses became increasingly likely to select (incorrectly) brand names with which they had preexisting familiarity…When recollection is poor, we often rely on familiarity.” Id. 

Perhaps the most important matter at issue is what role, if any, expert witnesses can play in unscrambling inaccurate memory testimony in asbestos litigation. In most cases, it is not permissible for an expert to testify to the effect that a lay witness identification of a specific product is incorrect, because such testimony would require irrefutable evidence of what took place decades ago. See id. However, in such cases, there is quite a bit that expert witnesses can do to help a judge or jury make a decision. One essential role that experts can perform, which was discussed in Part I of this article, is to act as memory experts, explaining how memory works “from a scientific standpoint” and addressing the issues that are known by the scientific community to affect the reliability of eyewitness or memory testimony. See id. Since the jury will determine the credibility of a particular piece of testimony, memory experts can go a long way towards helping jurors deliberate and ultimately determine if a lay witness’s memory testimony is credible or not.

The AP-LS noted the authors mentioned in the study discussed in Part I of this series and their findings, determining that: “The necessity of expert testimony in these cases is clear.” See id. Dr. Charles Weaver, a professor of psychology and neuroscience at Baylor University, tied Simon and Chablis’s[1] findings in with his own research on memory witnesses and experts years later, and made the same findings in an even more specific context, that of asbestos litigation.


Civil litigation involving memory testimony clearly needs expert witnesses to assist the trier of fact in reaching correct conclusions regarding memory functions and its limitations. Particularly because of the lapse of time between a party’s exposure to asbestos and the time litigation becomes ripe, even the most conscientious lay witness is extremely likely, though perhaps unconsciously, to experience somewhat faulty recollections in this type of litigation. As the AP-LS concludes: “The central issue of a civil case may hinge on a witness’s recollection of the distant past. Experts can assist the jury by providing a scientifically accurate explanation of human memory, correcting common misconceptions, and by identifying the factors that might influence recollection, things that a typical juror is not likely to know.” Id.