The Worst Witness is an Eyewitness:
A Guide for the Average Citizen & Potential Juror
Recently, I had a minor incident with my memory. As I was getting ready to leave my house for work, I gathered my things, made sure my briefcase was packed, and reached for my keys. I kissed the missus, patted the dog, and jogged hurriedly out the door. I got in the car, got situated, went to put the keys in the ignition, when I realized, for the first time, that I had no keys. I thought ‘I must have dropped them in the rear floorboard when I put my briefcase on the back seat,’ but they weren’t there. Then I thought ‘I must have dropped them on the ground somewhere between my front porch and my car,’ but after getting back out of the car and looking high and low, I couldn’t find them there either. I was perplexed, because I specifically remembered picking up those keys off of my desk, near the silver lamp, right next to my reading glasses. Puzzled — and now running late — I went back into the house and retraced my steps through the living room to the hall to the study, scanning all the way looking for those damn keys. Lo and behold I found them — on the desk, near the silver lamp, right next to my reading glasses. I never picked them up.
This incident cost me a rather mild annoyance. I was already running late, and was now a little later, because I would have sworn, under oath, that I picked up those keys before I left the house. I knew it, I was certain of it, and I was completely, 100% wrong. Is this an early sign of a failing memory or the onset of dementia? Maybe. But there is another at-least-equally plausible explanation for this short interval of temporary insanity, and it is one reason (among others) that eyewitness testimony is inherently unreliable — and easily manipulated. The phenomena of “gap filling” and reliance on assumptions frequently contribute to the formation of false memories. This process helps to create memories that are inaccurate, yet still allows the rememberer to testify truthfully about something that is absolutely false.
It is important to note that this failure of memory is perfectly normal, which is what makes it so potentially dangerous. It is perfectly normal for people’s brains to fill gaps and rely on assumptions, as these are necessary to function effectively in society. For instance, if we don’t expect traffic signals to change, or don’t expect the mail to arrive on a given day, our behavior would be markedly different. Unfortunately, this very useful ability can also lead to inaccurate recall of events, even when we are very confident that our memory is perfect. In fact, studies have shown that people who are “very confident” of their accuracy are no more accurate than people who aren’t so sure.
Memories are particularly susceptible to third-party interference, meaning that other people can unintentionally — or sometimes even intentionally — implant false memories in the minds of potential witnesses. This effect was studied by Elizabeth Loftus who performed experiments in the mid-seventies demonstrating the effect of a third party’s introduction of false facts into memory. Subjects were shown a slide of a car at an intersection with either a yield sign or a stop sign. Experimenters asked participants questions, falsely introducing the term “stop sign” into the question instead of referring to the yield sign participants had actually seen, and they falsely substituted the term “yield sign” in questions directed to participants who had actually seen the stop sign slide. The results indicated that subjects remembered seeing the false image. Subjects were also shown a slide depicting a car accident. Subjects were later asked how fast the cars were traveling when they “hit” each other, and other subjects were asked how fast the cars were traveling when they “smashed into” each other. Those subjects questioned using the word “smashed” were more likely to report having seen broken glass in the original slide. In other words, the introduction of false cues altered participants’ memories.
Loftus, who is one of the foremost experts on memory, reminds us that memories are not recorded and recalled like a video camera, but are basically reconstructed each time they are recalled. She stated that the act of remembering is “more akin to putting puzzle pieces together than retrieving a video recording.” Thus, many things, even innocent questioning by a police officer or lawyer, can alter a witness’ testimony because fragments of the memory may be unknowingly combined with other, or new, information.
Another reason why eyewitness testimony may be inaccurate comes about due to an eyewitness’s memory being influenced by things that they might hear or see after the crime occurred. This distortion is known as the “post-event misinformation effect” (Loftus and Palmer, 1974). After a crime occurs and an eyewitness comes forward, police try to gather as much information as they can to avoid the influence that may come from the environment, such as the media. Many times when the crime is surrounded by much publicity, an eyewitness may experience “source misattribution.” Source misattribution occurs when a witness is incorrect about where or when they have the memory from.
Furthermore, there have been several studies that tend to show that inherent bias may also affect memories. People rarely tell a story in a neutral fashion, and the witness’s own bias while recalling the witnessed event can distort the very formation of memory even without the introduction of misinformation from a third party. Thus, even the simple act of telling a detective or a prosecutor what happened could distort the witness’s memory of the event. It has been shown that witnesses are more apt to tailor their stories — and consequently their memories — to the interests of the first listeners. Therefore, an eyewitness to a crime is more apt to remember and recount incriminating details when speaking to a police officer or investigator intent on solving the crime.
Additionally, although some witnesses see the entirety of a crime happen in front of them, many witnesses only see part of a crime. These witnesses are more likely to experience confirmation bias. Witness expectations are primarily responsible for the distortion that may come from confirmation bias. For example, in one study, witnesses of a mock crime who did not witness the whole crime nevertheless testified to what they expected would have happened. These expectations are normally similar across individuals due to the details of the environment.
All these failures of memory make eyewitness testimony especially dangerous in criminal trials. Surveys show that most jurors place heavy weight on eyewitness testimony when deciding whether a criminal defendant is guilty, and this has likely led to countless wrongful convictions. Since the 1990’s the Innocence Project has used DNA evidence to exonerate hundreds of inmates who were wrongfully convicted. Of the convictions that were overturned, almost 75% of the convictions were obtained based on eyewitness testimony. At least one third of those cases rested on the testimony of two or more mistaken eyewitnesses.
Evaluating the credibility of eyewitness testimony falls on all jurors when such evidence is offered as testimony in a trial. Juries have been shown to rely heavily on eyewitness testimony and research has shown that juries are often unable to distinguish between false and accurate eyewitness testimony. Jurors often appear to correlate the confidence level of the witness with the accuracy of their testimony. In fact, this correlation was, at one time, written into the law through the 1967 Supreme Court decision in Manson v. Braithwaite, where the Court ruled specifically that the reliability of an eyewitnesses identification depends in part on the level of certainty that the witness expresses while testifying. In fact, the Court stated that this approach was simply “common sense.” Later research has shown this to be patently wrong — there is practically no correlation between witness confidence and accuracy.
There are currently very few protections and safeguards against inaccurate eyewitness testimony during a trial, despite the fact that courts have long recognized the questionable reliability of eyewitness testimony in criminal trials. As the U.S. Supreme Court noted half a century ago:
The vagaries of eyewitness identification are well-known; the annals of criminal law are rife with instances of mistaken identification. . . The identification of strangers is proverbially untrustworthy. The hazards of such testimony are established by a formidable number of instances in the records of English and American trials.
United States v. Wade, 388 U.S. 218, 228 (1967).
Likewise, the U.S. Court of Appeals for the Second Circuit stated in Jackson v. Fogg:
[C]onvictions based solely on testimony that identifies a defendant previously unknown to the witness are highly suspect. Of all the various kinds of evidence, it is the least reliable, especially where unsupported by corroborating evidence.
Even acknowledging the unreliability of eyewitness testimony, many courts still wont allow a party to call an expert witness to explain the shortcomings of such testimony. Judges often believe that juries are smart enough to figure out when someone is testifying falsely. Of course this approach completely ignores the volumes of evidence to the contrary. Studies definitively demonstrate that while it is no doubt true that all jurors have some everyday experience which is relevant to determining the reliability of eyewitness identification testimony, the type of research, information, and factors about which an expert would testify at trial may be imperfectly understood by many jurors or may be counter-intuitive. In other words, they are beyond the common knowledge of the average juror.(2)
As one study states:
. . . the present experiment provides strong evidence that . . . lay persons do not effectively integrate eyewitness evidence . . . [T]he findings lead us to argue, along with Loftus (1986), Woocher (1986) and Wells (1984), that jurors do not possess the knowledge and skills necessary to adequately assess the reliability of eyewitness identifications.
Cutler, Penrod and Stave, Juror Decision Making in Eyewitness Identification Cases, 12 Law and Human Behavior 41, 42 (1988).
There are some brave jurists out there that get it, such as Chief Judge Kay of a New York appellate court, who wrote in a dissenting opinion:
The notion that jurors are generally aware from their everyday experience of the factors relevant to the reliability of eyewitness observation and identification has not only been properly condemned as “makeshift reasoning” (see McCormick, Evidence § 206, at 624 [Cleary 3d ed]), but also has been refuted by research demonstrating a number of common and widely held misperceptions on the subject among laypersons (citations omitted).
People v. Mooney, 76 N.Y.2D 826, 832, 560 N.Y.S.2d 115, 118 (1990) (Kaye, J., dissenting).
As it stands, appellate courts generally leave it within the sound discretion of the trial courts whether expert testimony is admissible, and unfortunately, not enough trial courts are allowing it. This antiquated approach only leads to more wrongful convictions based on faulty eyewitness testimony, as the jurors are left believing in the reliability of eyewitness accounts. For the better part of four decades research has cast serious doubt on the veracity of eyewitness testimony, yet it still goes unfiltered and untempered to a jury. So beware the eyewitness, especially if you are ever called for jury duty. His testimony often carries the greatest weight, but not the best accuracy, and he can make his fiction some poor innocent defendant’s reality.