Another Miss By the Supremes

There are few other topics in applied psychology that have been more heavily researched than eyewitness identification. More than 2000 studies of the subject have been published in professional journals. Yet the influence of this research on the legal system has been painfully slow. There have been no major changes in federal law governing eyewitnesses since 1977. Earlier this month, the Supreme Court took a major step backwards.  This decision doesn't belong on the same CD with "Stop in the Name of Love."

In a series of cases between 1967 and 1977, the Supremes ruled that inaccurate identifications violate the due process rights of the defendant. Eyewitness testimony can be suppressed before it is presented to the jury if the identification is made under “suggestive” conditions. In previous cases before the Court, those biased conditions were orchestrated by the police. At issue in the present case: What happens when the eyewitness is exposed to a suggestive procedure for which the police are not responsible?

In Perry v. New Hampshire, a witness called the police at 2:30 a.m. to say she observed a black man breaking into a car from her fourth story window. The police apprehended Barion Perry, a black man, in the parking lot with stolen objects in his possession. When a policeman went to the witness's apartment to interview her, she on her own initiative went to the window and identified Perry, who was standing in the lot next to another officer. This is not a reliable identification, since the distance was great and the lighting was poor. Furthermore, the fact that Perry was standing in police custody made it inherently obvious that he was the suspect. In fact, the witness failed to pick Perry out of a photo array a month later. Nevertheless, the prosecution put her on the stand, and Perry was convicted.

Although this is counterintuitive to most people, we are not very good at identifying persons whom we observed for only a short period of time. Incorrect identifications are a common occurrence. Extrapolating from large-scale field studies, the American Psychological Association (APA), in a brief filed in the case, estimated that about one-third of eyewitness identifications are incorrect. The Innocence Project, using DNA evidence, has exonerated nearly 300 prisoners who were falsely convicted. In 76% of these cases, an incorrect identification was involved.

Variables that affect eyewitness accuracy can be divided into two categories: estimator variables, which take place at the time the eyewitness observes the crime, and system variables, which occur when the identification is made, many of which are, or should be, under the control of the state. Estimator variables include the length of time the suspect was observed, the distance, the lighting conditions, and whether the eyewitness is under stress, such as that produced by the presence of a gun. Cross-racial identifications are less accurate than when the suspect and the eyewitness are of the same race. System variables under the control of the police involve the fairness of the identification procedure. If a six-person lineup is used, all five non-suspects must fit the perpetrator's description, and to avoid bias, the officer who conducts the lineup should not be aware of the suspect's identity. The most error-prone identification procedure of all is the one-person showup. However, not all system variables are under police control, as Perry illustrates. Suggestive identification procedures can also be instigated by the media, or by friends of the witness.

The Perry case concerns a system variable that was not under police control, although you might argue that it should have been. The Supremes ruled 8-1 against Perry. The lead singer in this case, Justice Ruth Bader Ginsberg, writing for the majority, acknowledged that Perry's identification occurred under suggestive conditions, but said that eyewitness testimony can be suppressed only if the suggestive procedure was caused by police action. This excludes the possibility of suppressing eyewitness testimony that is unreliable due to estimator variables, or due to system variables not under police control. (Ironically, if the police officer had suggested that the witness look out the window, her testimony would probably have been excluded.) The justification for suppression of eyewitness testimony in previous cases, Justice Ginsberg argued, was to deter the police from arranging unfair or biased identifications. This is a very narrow reading of the language of previous eyewitness cases.

Justice Ginsberg noted that the defense attorney can try to discredit the eyewitness through cross-examination, making it clear to the jury that the identification took place under biased circumstances. However, research indicates that mock jurors “overbelieve” eyewitnesses; that is, they believe witnesses whose identifications are known to researchers to be false. Here's how it usually happens. The studies show that eyewitnesses are overconfident of the accuracy of their identifications. As a result, there is no relationship between their confidence and their accuracy. Jurors, in turn, base their judgments of the credibility of an eyewitness primarily on his or her confidence. Since witnesses are just as confident of incorrect identifications as correct ones, jurors are unable to distinguish between accurate and inaccurate eyewitnesses. Neither a warning from the judge nor expert testimony regarding the fallibility of eyewitnesses are sufficient to eliminate the tendency to overbelieve eyewitnesses. (See the APA brief for references to specific studies which support these conclusions.)

The only dissonant note in the case came from Justice Sonia Sotomayor. She argued that the real purpose of suppressing tainted eyewitness testimony is to prevent miscarriages of justice caused by incorrect identifications. For example, in Manson v. Braithwaite (1977), the court said that “the primary evil to be avoided” is the “likelihood of misidentification.” Deterring the police from using biased procedures is just one way of avoiding misidentifications. This suggests that the court should exclude eyewitness testimony that is a product of suggestive circumstances, regardless of whether those circumstances results from police action, police inaction, or sources other than the police.

It is profoundly discouraging to social scientists when the Supremes base their decisions on technicalities and fail to appreciate the overall implications of sound scientific research.