Next to a DNA match, many people probably think that eyewitness identification is most persuasive. Yet, this persuasive evidence is often wrong. It is not wrong because witnesses lie, although some of them may. It is wrong because our memories play tricks with us. The recent tragedy in Ferguson, Missouri, illustrates the problem. We know that a police officer, Darren Wilson, killed Michael Brown, an unarmed 18-year old black man. Wilson said it was self-defense but other witnesses contradicted him. Because the police officer is white and the deceased black, the tragedy was the occasion for many comments about racism. Yet, this episode also illustrates the problems with eyewitness identification.
Robert McCulloch, the St. Louis County Prosecutor, used the grand jury to investigate the incident to determine if the tragedy was a crime. Did Officer Wilson have the “reasonable belief” that he needed to use deadly force to defend himself? McCulloch released the grand jury testimony, and when he did so he warned us of the dangers of eyewitness identification.
Many witnesses to the shooting of Michael Brown made statements inconsistent with other statements they made and also conflicting with the physical evidence. Some were completely refuted by the physical evidence.
As an example, before the results of the private autopsy were released, witnesses on social media during interviews with the media and even during questioning by law enforcement claimed that they saw Officer Wilson stand over Michael Brown and fire many rounds into his back.
Others claim that Officer Wilson shot Mr. Brown in the back as Mr. Brown was running away. However once the autopsy findings were released showing that Michael Brown had not sustained any wound to the back of his body. No additional witnesses made such a claim. And several witnesses adjusted their stories in subsequent statements.
Some even admitted that they did not witness the event at all but merely repeated what they heard in the neighborhood or others or assumed had happened. Fortunately, for the integrity of our investigation, almost all initial witness interviews including those of Officer Wilson were reported.
Was Brown running away from Office Wilson, charging towards him, or staggering? For example, one witness said, “I thought he was trying to charge him at first because the only thing I kept saying was is he crazy?” In contrast, another witness testified, “I didn’t get the impression of a charge because it wasn’t fast enough to be a charge.”
While eyewitness accounts varied, that was not the case with the two two autopsy reports provided to jurors. St. Louis County performed one autopsy and Michael Baden, a nationally known forensic pathologist, performed the other, at the family’s request. Both concluded that Mr. Brown was shot in the head, face, chest area and arms; he was not shot in the back.
Empirical evidence supports the conclusion that eyewitness identification is often unreliable. One study examined eyewitnesses who were intoxicated. One group had a .04 blood alcohol concentration for one group; the second had .07-alcohol concentration; the third group, the control group, was alcohol-free. The typical blood alcohol-driving limit in the United States is .08, so the second group was barely able to drive legally. The experimenters showed each group a staged kidnapping. One week later, the study asked everyone to pick out the kidnappers out of a line-up. All three groups performed about the same, which was slightly better than chance. There were no significant effects of alcohol intoxication with respect to performance. I bet you did not see that coming. It gets worse.
In the more than 250 convictions overturned because of DNA evidence, 73 percent involved cases where the error was attributable to misidentifications by eyewitnesses. In criminal cases, 38 percent of the exonerations involving mistaken identify included multiple eyewitnesses. Exonerations show that misidentification is involved in 27 percent of homicides but in 80 percent of sexual assault cases. That should not be surprising, because experts tell us that memories that are emotionally negative have greater potentiality to be flawed.
The Report by the National Registry of Exonerations concluded that that there were 873 exonerations, entered in the Registry as of March 1, 2012. Of this group, DNA evidence helped exonerate 37 percent; 63 percent were exonerated without the use of DNA. Since 2000, exonerations have averaged 52 a year, or one a week, and 40 percent of them include DNA evidence. The most common causal factors that contributed to the exonerations are (1) perjury or false accusation (51 percent), (2) mistaken eyewitness identification (43 percent), (3) official misconduct (42 percent), (4) false or misleading forensic evidence (24 percent), and (5) false confession (16 percent). As of December 9, 2014, the National Registry reported 1,490 exonerations.
Some courts are starting to take notice. In 2012, the Oregon Supreme Court considered the case of a criminal defendant who seeks to exclude eyewitness identification evidence in a pretrial motion. If the defendant argues that the witness lacks personal knowledge, the opposing side “must offer evidence showing both that the witness had an adequate opportunity to observe or otherwise personally perceive the facts to which the witness will testify, and did, in fact, observe or perceive them, thereby gaining personal knowledge of the facts.”
The National Association of Criminal Defense Lawyers (NACDL) [full disclosure, I have written and filed pro bono briefs for the NACDL] has encouraged the use of “double-blind” lineups. Double-blind tests are routine in the sciences but not in line-ups. With a double-blind sequential lineup procedure, the police show the suspects, one by one, to the witness. That reduces the possibility of a witness picking the person who looks most like the culprit even if that person is not the culprit. Moreover, the “double-blind” procedure means that the police officer who conducts the procedure does not know the identity of the suspect. That prevents the officer from (unconsciously or consciously) providing visual cues to the witness.
In October 2014, the National Research Council of the Academy of Sciences published a report evaluating eyewitness identification. The authors were—and this is a mouthful—the Committee on Scientific Approaches to Understanding and Maximizing the Validity and Reliability of Eyewitness Identification in Law Enforcement and the Courts; Committee on Science, Technology, and Law; Policy and Global Affairs; Committee on Law and Justice; Division of Behavioral and Social Sciences and Education; National Research Council. The Report warns us many factors compromise our memory, from the time we initially process the event to the time later when we retrieve it. “Unknown to the individual, memories are forgotten, reconstructed, updated, and distorted.” The Report also recommends adopting “blinded” eyewitness identification procedures.
Police, prosecutors, victims, and the public are all interested in apprehending the guilty. However, a wrongful conviction does nothing to deter wrongful conduct because the wrong person is found guilty. If anything, it can encourage wrongful conduct because the guilty person is still loose. That guilty person still on the loose is the only party with an interest in not improving eyewitness identification.