Expert testimony on eyewitness identification: a new pair of glasses for the jury.

• Author: Handberg, Roger B.

INTRODUCTION

"[T]here is almost nothing more convincing than a live human being who

takes the stand, points a finger at the defendant, and says `That's the

one!'"

--Justice William Brennan(1)

In the artificial environment of a trial, eyewitness identifications assume an importance that often does not reflect their accuracy. While scientific studies have shown that eyewitness observations are not always a reliable source of evidence, many people still place great weight on them. One study estimates that half of all wrongful convictions result from false identifications.(2) This empirical data is supported by anecdotal accounts of inaccurate identifications leading to the convictions of innocent persons.(3)

Numerous commentators have argued that the best way to avoid inaccurate eyewitness identifications is to allow experts to testify on the accuracy of such identifications.(4) Despite these pleas and the wealth of scientific evidence which confirms that eyewitness identifications are often unreliable, most courts have refused to allow defendants to use expert testimony on eyewitness identification.(5) Even those courts that have allowed expert testimony have done so on a limited basis.(6)

The courts, rejection of expert testimony on eyewitness identification is curious, given their allowance of similar testimony in other contexts. For instance, courts have been increasingly willing to accept expert testimony on Child Sexual Abuse Accommodation Syndrome (CSAAS) and Rape Trauma Syndrome (RTS). With respect to CSAAS, courts allow such evidence because it corrects the mistaken impression that a child's inconsistent stories or delay in reporting abuse means that the child fabricated the abuse charge.(7) Courts permit expert testimony on RTS to correct similar mistaken impressions about counterintuitive post-rape behavior or a delay in a victim's report of a rape.(8)

This article argues that courts should admit expert testimony on eyewitness identification in much the same way that they allow it on CSAAS and RTS. Part I describes the scientific studies which suggest that eyewitness identifications are often unreliable and that eyewitness expert testimony could help correct jury misperceptions. Part II analyzes the Federal Rules of Evidence and argues that eyewitness expert testimony is consistent with those rules. Part III outlines the current judicial approaches to the use of expert testimony on eyewitness identification. An analysis of these approaches indicates that courts are concerned that juries will not be able to properly weigh expert testimony because it addresses witness credibility. Recognizing that courts are intuitively uncomfortable with expert testimony on credibility, Part IV encourages courts to look at eyewitness expert testimony as they do at expert testimony on CSAAS and RTS.

Nevertheless, while expert testimony on eyewitness identification is helpful in many situations, those courts which reject it raise a valid concern about its use. Unlike other expert testimony, eyewitness expert testimony often concerns information that is within jurors, common sense. That is, the eyewitness expert does not testify about matters unfamiliar to a layperson, such as real estate appraisal or proper medical treatment. Instead, the eyewitness expert describes the memory process and what might lead an eyewitness to make an improper identification. Because the jury has some understanding of this memory process based upon personal experience, many courts worry that jurors might disregard their experience and defer to the expert.

Part V argues that this concern is warranted, especially because the science underlying eyewitness identification is general and not applicable in all situations. Indeed, courts should worry about jurors deferring too much to experts whose testimony may not apply to a particular set of facts. The best protection against juror overreliance on eyewitness expert testimony is to encourage jurors to use the expert testimony as a supplement to, not a substitute for, their personal knowledge. There are various techniques courts might use to achieve this end, such as appointing an expert, excluding jurors who are unaware of the problems associated with eyewitness identification, and giving a jury instruction before the expert's testimony. None of these techniques are perfect. Nevertheless, after analyzing the benefits and detriments of each one, this article argues that a jury instruction preceding the expert testimony would best achieve the goal of encouraging the jury to use its common sense when considering whether to apply the expert testimony.

1. SCIENTIFIC EVIDENCE

   Over the past twenty years, psychologists have conducted a great deal of research on the phenomenon of eyewitness identification.(9) Because it is impossible to cover all of this research, this section is limited to a discussion of the most important findings. Part I.A. presents a hypothetical case intended to focus the discussion of scientific evidence about eyewitness identification on a few illustrative topics. Part I.B. outlines what psychologists have learned about those topics. Part I.C. explores the issue of whether juries comprehend the impact that the identified factors have on eyewitness identification.

   1. Eleven O'Clock Hypothetical

      At eleven o'clock at night, a black woman is walking alone in a residential part of a city. As she turns the corner, she hears the sound of a car door slamming across the street. A black man gets out of the car and jogs to the woman's side of the street. While he is running, he asks the woman to stop for a moment. Despite his requests, the woman quickens her pace. Yet, after one-third of a block, the man catches up. He positions himself in front of her and asks her if she has any money he can borrow to get a tow truck. After thirty seconds of saying no to his repeated requests, she tries to leave. At this time, the man pushes her to the ground, pulls a gun, and demands that she give him the money. She hands over the contents of her wallet, including several credit cards.

      While no one else was on the street and no cars drove by, the white owner of the house in front of which the robbery occurred witnessed the event from the moment the robber pushed the woman down and demanded money. He had been reading in a family room adjacent to the street. When he heard their voices outside, he looked through his front window and saw a man push a woman down and produce a gun. He saw the robber's face several times from a distance of twenty feet.

      After the robber ran away, the man called the police and went outside to help the woman. Down the street, he saw car lights come on as a car started up. The car drove away and turned two blocks down the road.

      A day later, the police contacted the woman and asked her to come down to the station. They had located an abandoned car the night before four miles from the scene of the robbery. On a hunch, the police staked out the area in the hope that someone would return for the car. When a tow truck arrived for the car in the morning, the police approached the two men in the tow truck. After brief questioning, one person identified himself as the tow truck driver, the other as the car's owner. The police asked the car owner for some form of personal identification. When the car owner opened his wallet, several credit cards fell out. Each card was imprinted with the victim's name. The police arrested the car owner, took him to the station, and called the woman in to make a positive identification.

      When the woman arrived at the station, the police arranged a line-up consisting of the car owner and five other men with similar physical characteristics. The police asked the woman to pick the robber out from the line-up. After five minutes, the woman pointed to the car owner and said, "I think that is him. No.... Yes, that is him."

      The police attempted to contact the other eyewitness, but he had flown out earlier that morning for a previously scheduled three-month trip overseas. When he returned and received the message from the police, he went to the station and immediately picked the car owner out of a six-man line-up.

   2. Unreliable Elements of Eyewitness Identifications

      Many laypersons believe that human memory works like a videocassette recorder.(10) In essence, we remember what we see and can reproduce those recollections when needed. Psychological studies indicate, however, that memory is really a complex process consisting of three stages: (1) acquisition, (2) retention, and (3) retrieval.(11) In each of these stages, various factors can alter a witness's perception of an event and render it unreliable.(12) For example, in the Eleven O'Clock Hypothetical there are several factors in each stage which a jury should consider in deciding whether the identifications are reliable.

      1. Acquisition

         The acquisition stage covers the witness's perception of the original event.(13) Factors in this stage fall into two categories: event factors and witness factors. As their names imply, these factors describe the circumstances surrounding the event and the witness, respectively. In the Eleven O'Clock Hypothetical, each of these factors has at least two manifestations.

         1. Event factors

            An event factor is something inherent in an incident which affects one's ability to perceive it accurately.(14) One event factor present in the Eleven O'Clock Hypothetical is the duration of the event.(15) In general, the reliability of an eyewitness identification diminishes as the viewing time decreases.(16) Thus, the woman, who saw the robber for over thirty seconds, was in a better position to make a reliable identification than the man (who saw the robber for a much shorter period of time).(17)

            Similarly, violence--a second event factor found in the Eleven O'Clock Hypothetical--suggests that the woman's eyewitness identification may be more reliable than the man's. Witnesses to a violent...