07/03/07 (FL):
Eyewitness ID Testimony Inherently Unreliable Says Expert
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Long a staple in criminal trials, the testimony of eyewitnesses in attempting to identify the person who committed a crime can be far from accurate, an expert testified recently in a 21st Judicial District Court case.
Had the robbery case been tried before a jury, rather than a judge alone, the testimony of the specialist in eyewitness identification would not have been allowed. Because the defendant had waived his right to a jury trial, the judge permitted the testimony of Robert Shomer, an experimental psychologist who has taught at Harvard and UCLA.
Scientific tests have shown that eyewitness identification often is inaccurate when the witness was in a stressful situation at the time of the incident, Shomer said. In one example, he said a test of 500 U.S. Army Special Forces members subjected to stress showed only 30 percent accuracy in identification. Shomer has testified as an expert several hundred times, but rulings on whether such testimony can be presented to a jury varies from state to state. In upholding judges who disallowed such testimony, the Louisiana Supreme Court said the "prejudicial effect" of an expert questioning reliability of eyewitness testimony could "have a greater influence on the jury than the other evidence presented during the trial."
Greg Murphy, the prosecutor in the case in which Shomer testified, said he thinks the Supreme Court is correct. It's the jury's role to decide the credibility of witnesses, Murphy said. "Jurors don't need an expert to tell them what they already know from common sense."
Allen Harvey, the public defender in the case, maintained that expert testimony on how memory works and its reliability in identification is important information.
"It's something jurors need to know," Harvey said after the trial. "Lay jurors tend to have more confidence in eyewitness identifications than they ought to have."
Shomer also had a lot to say about the results of tests on how police lineups are conducted.
For a picture lineup to be fair, the pictures must be presented in the same format and should match the initial description of the perpetrator to the same extent, he said.
In the case in which Shomer testified, the lineup contained six photographs, five of which were in color. The photograph of the suspect was in black and white.
Like a scientific study, a photo lineup should be presented in a double blind manner, he said. When the effectiveness of a drug is being studied, the nurse actually administering the drug shouldn't know which patients are receiving the real drug and which are getting the sugar pills. That way, the nurse can't, either consciously or accidentally, provide any indications to the patients, Shomer said.
In a photo lineup, the person showing the pictures to the witness shouldn't know which photo is that of the suspect. Without intending to do so, a police officer might provide the witness with subtle clues as to which picture is that of the suspected person, Shomer said.
Using such a double-blind procedure is a strong recommendation of the American Bar Association, Shomer told the court.
Instructions to the witness should include the admonition that the perpetrator might not be in the lineup. Otherwise a witnesses assumes one photo is of the perpetrator and the witness feels pressured to choose one.
Studies also have shown that the reliability of eyewitness identification falls rapidly with time. After 24 hours "there's an enormous increase in the amount of error," Shomer said.
When DNA evidence resulted in the exoneration of a person found guilty of a crime, eyewitness identification often was the evidence upon which the defendant was convicted. In fact, the No. 1 cause of wrongful conviction is from eyewitness identification, Shomer said.
The Livingston Parish case in which Shomer testified involved witnesses identifying the suspect's picture in an armed robbery. Shomer's testimony didn't deter the judge from finding the defendant guilty, though the conviction was on a lesser charge.
© X-Pro 2007
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