Criminal Justice

Ferguson case demonstrates the potential shortcomings of eyewitness testimony

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The most credible eyewitnesses to the shooting of 18-year-old Michael Brown said the youth charged toward Ferguson, Missouri, police officer Darren Wilson when the officer fired the fatal shots, according to St. Louis County Prosecuting Attorney Robert McCulloch.

But eyewitness reports differed, McCulloch said, and some witnesses clung to their accounts even when confronted with physical evidence contradicting their reports. Others changed their accounts when confronted with the evidence, including autopsies that showed Brown was not shot in the back, he said. And some conceded they didn’t actually see the shooting at all, the Washington Post reports.

“At least one witness stated that as Officer Wilson got out of his vehicle, he shot Mr. Brown multiple times as Mr. Brown stood next to the vehicle,” McCulloch said. “Yet another witness stated that Officer Wilson stuck his gun out of the window and fired at Mr. Brown as Mr. Brown was running. One witness stated there were actually two police vehicles and four officers present, but only one officer fired a weapon.”

“I think they truly believe that’s what they saw, but they didn’t,” McCulloch said of the witnesses to the incident, in response to a reporters’ question.

The differences wouldn’t surprise researchers who have noted problems with eyewitness testimony, according to the Washington Post story. Many people think the human memory acts like a videotape or a DVD, but in reality human memory can be faulty.

Witnesses fill holes in their memory with assumptions, and memories can be skewed by what friends say, accounts on TV, and what the witness wanted to see, the story says, citing research by psychology professor Barbara Tversky of Columbia University. Once an inaccuracy becomes lodged in memory, people may be unwilling or unable to reconsider their recollection.

A Scientific American story recounts research on the issue by University of California at Irvine memory researcher Elizabeth Loftus.

In one study by Loftus, test subjects were given written accounts of three events they had actually experienced and a fictional fourth event in which a relative recalled the subject being lost at a public place as a young child. The test subjects were then asked to recall their actual memories of the incidents.

“Remarkably about one third of the subjects reported partially or fully remembering the false event,” Scientific American says. “In two follow-up interviews, 25 percent still claimed that they remembered the untrue story, a figure consistent with the findings of similar studies.”

Factors that can reduce the accuracy of eyewitness identifications include stress at the crime scene, and the presence of weapons at the crime scene, which increase the stress.

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