By Roger L. Terry, Xlibris Corporation, Philadelphia, Pa. 316 pages; hardbook, $29.99; paperback, $19.99

Psychologist Hugo Munsterberg wrote in 1908 that science could help the legal system understand the vagaries of eyewitness testimony. It was not until nearly 70 years later, in the late 1970s and throughout the 1980s, however, that psychologists began in earnest to test the accuracy of eyewitness accounts. When they did, their publications contained strong admonitions that eyewitness testimony, a great influence on jurors, is highly fallible.

With universal reliance on eyewitness identification in the legal system, it is troubling but not surprising that lawmakers are reticent to listen to expert testimony on eyewitness reliability and the mind’s malleability to a host of factors. Defense attorneys try to introduce expert testimony to diffuse the weight jurors attach to it, while prosecutors fight to exclude it by arguing that it invades the juror’s role, and that cross-examination or proper limiting instructions by the court (focusing on witness’ ability to perceive and recall) provide adequate opportunity for jurors to gauge witness credibility.

‘Eyewitness Identification: A Lawyer’s Resource for Expert Testimony” by Roger L. Terry structures the body of scientific research pertaining to eyewitness identification in the form of a model direct examination of expert witnesses. The research summaries reveal the complexities of how we store and retrieve information, so that even with disagreements between researchers, inconsistencies in findings, and gaps in the research, we deduce that lay persons cannot intuit the complexities of eyewitness testimony. The book helps advance the field in a practical way by educating lawyers about the many factors known to affect eyewitness testimony to best elicit answers from experts that will be useful to triers of fact.

Terry explains that a range of factors relate to the mental processes of encoding, retention and retrieval of a sensory observation of a criminal perpetrator. Encoding is the process involved in registering knowledge of the external world. Retention is the time between encoding and retrieval, and retrieval concerns the methods we use to evoke memories – recall and recognition – that may compromise eyewitness accuracy but that are unknown to most jurors, who usually attach great credibility to eyewitness accuracy. Terry writes that “Facial encoding appears to be especially demanding and time consuming,” and explains that the process of encoding in humans is a slow one and is affected by many factors, from lighting, violence, duration of exposure and presence of a weapon, among others. Perpetrator factors affecting encoding involve the attractiveness of the perpetrator, gender, race, and disguise, among others. Eyewitness factors include visual acuity, age, race, ethnicity, stress, test expectation, stereotypes and more.

“Eyewitness Identification” is, at times, arduous to penetrate intellectually but the subject matter compels those concerned with procedural fairness to stick with it. Terry might have facilitated the processing of so much information by breaking down some of the model interrogatives, in which occasional long statements of fact precede the actual questions.

Despite several areas in which more research is needed, and a frustrating trend of inconclusive, inconsistent results or difficulties in interpretation, certain disquieting truths emerge.

Memory is malleable and highly suggestible. A person may honestly believe in the truth of his or her identification even though it is erroneous. Factors such as stress, duration of exposure, stereotypes, and type of lineup have measurable influence on the witness’ belief that his or her identification is accurate.

So does the introduction of bias in questioning by police, as demonstrated in an experiment by E.F. Loftus and J.C. Palmer in which students watched a film showing a two-car accident and were asked: “About how fast were the cars going when they (contacted, hit, bumped, collided with or smashed into) each other?” The word “smashed” connoted greater speed than the word “contacted.”

The level of confidence displayed by witnesses has a great effect on jurors who generally believe more confident eyewitnesses than less confident ones.

In fact, the U.S. Supreme Court in Neil v. Biggers, 409 U.S. 188 (1972), lists confidence as one of the factors jurors should consider in deciding the likelihood of misidentification.

Terry notes that literature reviews suggest a less significant relationship between confidence and accuracy than jurors, police, judges and prosecutors have assumed. Related to confidence is the kind of feedback that witnesses receive from police during photo spreads and lineups. As Terry writes:

It turns out that confidence is highly malleable. It can be increased or decreased by numerous influences that have nothing to do with the accuracy of the witness’ testimony . . . . [E]xperimental witnesses who were forewarned and briefed concerning an impending hostile cross-examination and were told to prepare to have the credibility of their testimony and the accuracy of their identification . . . challenged increased their confidence following the cross-examination more than unforewarned witnesses did.

This effect is greater for inaccurate witnesses.

Eyewitness confidence in suspect lineups can be manipulated by feedback from lineup administrators. Research shows that positive feedback can increase witness confidence, an effect that (once again) seems greater among inaccurate witnesses.

Terry writes that the debate over whether experts in eyewitness testimony should testify has shifted more to how they should testify. Still, not all jurisdictions allow expert testimony.

The results of at least one study suggest that expert knowledge might be of assistance to jurors. In comparing experts’ knowledge with laypersons’ (who may believe they have common sense and a basic grasp of psychology) the findings, according to Terry, “would indicate that much of the research on eyewitness accuracy is not intuitively obvious to laypersons and that laypersons could benefit from an increase in knowledge.”

Acknowledging the fallibility of eyewitness evidence after a rash of cases in which innocent inmates were exonerated by DNA evidence, in 1999 the National Institute of Justice assembled researchers, law enforcement and legal practitioners to begin improving protocols for collecting and preserving eyewitness evidence.

Their handbook, “Eyewitness Evidence: A Guide for Law Enforcement,” lays out what it calls “rigorous criteria for handling eyewitness evidence that are as demanding as those governing the handling of physical trace evidence.”

Such a standard is proper and readers of “Eyewitness Identification” will no doubt come away hoping that such criteria will include routine and regular testimony in all courts by experts in eyewitness testimony.

Heidi Boghosian is the executive director of the National Lawyers Guild.