Legal Update

Eyewitness Memory in Civil Litigation

Issues with hearing testimony from firsthand witnesses during trial.

By Charles A. Weaver, III

Expert testimony regarding the reliability (or lack thereof) of eyewitness testimony in criminal cases is now common. Thanks in part to the widely-publicized efforts of organizations like the Innocence Project, many prospective jury members are aware that even confident witnesses can be wrong. Furthermore, through the efforts of researchers like Loftus, Wells, and others, a set of “best practices” for eyewitness identification has emerged, and a number of different jurisdictions have altered police procedures to accommodate those practices.

Memory plays a central role in civil litigation, as well. Consider lawsuits involving product liability: in order to win a judgment, witnesses must remember precisely which products they used, and when. Although researchers and legal scholars are most familiar with problems of witness reliability in criminal cases, the demands on witnesses' memories are often more daunting in civil litigation, particularly those involving mesothelioma resulting from alleged asbestos exposure.

Mesothelioma is a relatively rare form of cancer, with only a few thousand cases reported each year in the USA. Because of the strong link between asbestos exposure and mesothelioma, those diagnosed often initiate lawsuits against companies that produced or distributed asbestos-containing products, or operated facilities where these products were used. Only a few thousand new lawsuits are filed each year, and competition among plaintiff's firms to represent these individuals is high (hence the frequent cable TV and radio advertisements). This competition is understandable: Thomson Reuters estimates, based on cases reported in Westlaw Journal Asbestos, that the average award (either a jury verdict or out-of-court settlement) ranged from $6.3 million to $17.6 million in the three-year period beginning in 2009 (Berkowitz, 2012). Many of the largest producers or suppliers of asbestos-containing products are long-since bankrupt. Johns-Manville, linked primarily to asbestos- containing insulation, filed for bankruptcy in 1982; more than 100 companies have since followed. As a result, most current lawsuits focus on secondary companies: for example, those which produced construction supplies like joint compound or caulk (some brands contained small amounts of asbestos until the mid-1970s), those supplying gaskets used in plumbing (some were cut from asbestos), or manufacturers of floor tile or roofing shingles (some of which may have incorporated asbestos fibers).

Witnesses in asbestos lawsuits face difficult conditions. First, the latency period for mesothelioma is often between 20-50 years. Plaintiffs must recall, then, products used decades earlier. Second, witnesses must recall not only the kinds of products they saw, but also the manufacturer and even the specific brand name of those products. Manufacturers often made several different versions of a product, not all of which contained asbestos. Third, witnesses must also identify the precise time period when the product may have been used. For those brands that did contain asbestos, most did so for a limited period of time. Fourth, individuals must recall details about products and events whose significance was likely not apparent when the products may have been used. The fact that today the brand of joint compound used by one's father in 1969 is vitally important does little to improve one's memory. Indeed, Kassam, Gilbert and colleagues demonstrated that the motivation to remember is significantly more effective when that motivation occurs before (not after) an event is encoded (Kassam, Gilbert, Swencionis, & Wilson, 2009). Finally, many plaintiffs worked around but not directly with asbestos-containing products. They must, in effect, recall the brands of products used by co-workers in the 1960s, products they may only have seen out of the “corner of their eye.”

Unlike criminal litigation, there are few restrictions on how witnesses may be prepared before making identifications. Some plaintiffs research asbestos-containing products on-line, and some plaintiff's firms show witnesses lists or photographs of asbestos-containing products prior to or during depositions. In the late 1990s, a witness-preparation memo written by one plaintiff's firm was inadvertently shared with defense attorneys. In addition to viewing photographs of asbestos-containing products, witnesses were given the following instructions:

“You may be asked how you are able to recall so many product names. The best answer is to say that you recall seeing the names on the containers or on the product itself. The more you thought about it, the more you remembered!”

“You will be asked if you ever saw any WARNING labels on containers of asbestos. It is important to maintain that you NEVER saw any labels on asbestos products that said WARNING or DANGER.” (Emphasis in the original).

Whether these practices reflect zealous representation on behalf of clients or something more serious is beyond the scope of this article (for an extensive discussion of the legal issues involved, see Brickman, 2004). The publication of this document initiated my involvement in asbestos cases. An attorney representing an asbestos defendant sent me the materials that had become available, and asked what effects this kind of preparation might have on one's memory. Lindsay, Garry, and Loftus, among others, were beginning to demonstrate the ease with which rich, elaborate—but false—memories can be created through suggestion and photographs (for an excellent review, see Frenda, Nichols, & Loftus, 2011). I suspected the same might be true in some cases here.

During the past few years, we have performed a number of experiments confirming our suspicions. In most of our studies, participants mix (or observe others mixing) kitchen ingredients (things like flour, sugar, and baking powder). Later, we ask these individuals not just the types of products they used, but also the brands. Using paradigms modeled on prior research in eyewitness memory, we found strong misinformation effects with brief, transient suggestions. If we mentioned in passing that “the Gold Medal flour container wasn't a normal size. Was it smaller or larger?,” people were much more likely to misidentify Gold Medal on subsequent tests. Likewise, with longer retention intervals witnesses became increasingly likely to select (incorrectly) brand names with which they had preexisting familiarity. This familiarity bias is consistent with what we know about preexisting familiarity and source monitoring in witnesses of criminal events. When recollection is poor (or even absent), we often rely on familiarity.

Finally, we investigated whether refreshing witnesses with photographs prior to identification was as powerful as we suspected. We used the same kind of kitchen products, but prior to final testing we presented witnesses with selected photograph saying only, “Use these pictures to jog your memory.” For all practical purposes, witnesses identified only products they had seen in photographs, regardless of what they had actually experienced. To examine how powerful photographs could be, we used Photoshop to create brands of products that don't actually exist: things like Smucker's Barbeque Sauce and Sara Lee Mayonnaise. Following situations where witnesses did see barbeque sauce or mayonnaise (but obviously, not really Smucker's or Sara Lee), we showed them these fictitious photos prior to identification. Roughly one-fourth of our participants later identified these fictitious products as ones they had used. A good summary of our research can be found in Weaver, Krug, Terrell, Holmes, and Parra (2012).

What are the central issues in asbestos cases?

When evaluating the evidence in asbestos cases, critical questions to ask include the following:

1. When did the events in question take place? Most experiences date back 30 years or more.

2. Did the witness interact with the products in such a way that attention would have been directed to the specific brand name of the products in question, at the time the product was used? That is, would the brand of the product have been important? As we know from the classic penny demonstration of Nickerson and Adams, rote repetition alone is not usually sufficient for producing reliable memories.

3. What kind of post-event information did the witness experience? Did they review photographs or lists of products, or do research on-line?

4. Is the brand name of the product in question likely to have been rehearsed during the past decades? Did the individual have any reason to continue to think about the products that may have been used in the 1960s or 1970s?

5. Can the witness recall other details from the time frame in question?

6. Can the witness recall the brands of other, non-asbestos-containing products that may have been used during the time frame in question?

7. How old would the witness have been during the critical time period? In a number of cases, the witness would have been a child observing others work with products. Children are considerably less likely to recall the brand name of a product used in auto or home repair— they simply attend to different things, for example. Before age 4 or 5, the offset of childhood amnesia, one would expect children to recall nothing at all about these incidental experiences.

8. To the extent that other witnesses are available, do they provide independent corroboration? Witnesses that collaborate or have personal or familial relationship cannot be considered independent.

9. How were witnesses questioned? How were companies identified?

Finally, it is critical to note that whether an expert witness would help the plaintiff or the defendant depends entirely on the fact pattern in a given case. Experts do not simply say, “Old memories are unreliable.” In a number of cases I've reviewed in the past decade, a witness's identification of a particular product is plausible. A witness may have had a particular reason for selecting a certain brand of product, for example. Expert testimony in those cases would benefit the plaintiff, not the defendant.

What role can the expert witness play in such cases? Clearly, in the vast majority of cases, experts cannot testify that a witness's identification of an individual product is wrong. To do so would require objective, incontrovertible evidence of what really transpired 30 or 40 years ago. Additionally, experts cannot offer testimony questioning the credibility of a witness. Credibility determinations are appropriately left to the jury. In fact, in a case where a witness is clearly not credible, expert testimony may not be necessary. Experts can, however, explain to the jury how memory works from a scientific standpoint, and discuss some of the factors known to influence the reliability of witnesses. The members of the jury can use this information as they evaluate eyewitness testimony in their deliberations.

The necessity of expert testimony in these cases is clear from recent survey data collected by Simons and Chabris (2011). Using standard sampling techniques, Simons and Chabris contacted nearly two thousand participants broken down by various educational, racial, and socioeconomic variables. They asked participants whether they agreed with a number of statements related to memory, such “Human memory works like a video camera, accurately recording the events we see and hear so that we can review and inspect them later.” More than 60% of those surveyed agreed with this statement, and more than half agreed with the statement, “Once you have experienced an event and formed a memory of it, that memory does not change.” For comparison, Simons and Chabris asked the same questions of memory researchers (university professors with at least ten years of experience as publishing memory researchers, myself included, attending the Psychonomic Society annual meeting in November, 2010). Not a single memory researcher agreed with the statements above. Although many in the legal system believe that a thorough and complete understanding of memory is common knowledge to a typical juror, these data demonstrate otherwise. The central issue of a civil case may hinge on a witness's recollections 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.


Berkowitz, B. (2012, May 11). Special Report: The long, lethal shadow of asbestos Retrieved July 1, 2013, from asbestoslawsuits-idUSBRE84A0J920120511

Brickman, L. (2004). On the theory class's theories of asbestos litigation: The disconnect between scholarship and reality. Pepperdine Law Review, 31, 33-170.

Frenda, S. J., Nichols, R. M., & Loftus, E. F. (2011). Current issues and advances in misinformation research. Current Directions in Psychological Science, 20, 20-23. doi: 10.1177/0963721410396620

Kassam, K. S., Gilbert, D. T., Swencionis, J. K., & Wilson, T. D. (2009). Misconceptions of memory: The Scooter Libby effect. Psychological Science, 20, 551-552.

Simons, D. J., & Chabris, C. F. (2011). What people believe about how memory works: A representative survey of the U.S. population. PLoS ONE, 6, e22757. doi: 10.1371/ journal.pone.0022757

Weaver, C. A., III, Krug, K. S., Terrell, J. T., Holmes, A. E., & Parra, K. F. (2012). Eyewitness memory Issues in civil litigation. In A. Jamieson & A. Moenssens (Eds.), Wiley Encyclopedia of Forensic Science: Behavioral Sciences (pp. 1-5). Chichester, UK: John Wiley & Sons, Ltd.