During a trial set to wrap up Tuesday in federal court in St. Paul, more than a dozen eyewitnesses testified about an alleged fistfight between former Navy sniper Chris Kyle and former Navy frogman Jesse Ventura.
Kyle said in a taped deposition that he punched Ventura because the former Minnesota governor was criticizing fallen soldiers. His friends testified they remember it that way, too -- although even they disagree on exactly what happened where.
But Ventura said nothing of the sort happened, and his companions backed him up. After Kyle talked about the incident in publicity tours for a best-selling autobiography he wrote before his death in 2013, Ventura sued for defamation.
During their deliberations, the jury will have to assess the credibility of the two sides. The differing stories of people who saw and heard bits and pieces of what went on at a San Diego-area bar in 2006 exemplify a hot issue in the legal world: memory.
For example, if in a court case two eyewitness versions of an event are extremely different, does it necessarily follow that somebody's lying? If an eyewitness on the stand points at the defendant to identify him as the culprit, how does that affect the jury? And what kinds of situations affect whether someone's memory can be counted on?
University of Minnesota Law School associate professor Francis Shen literally wrote the book on how memory issues can show up in the police station, the district attorney's office and the courtroom. He published the casebook "Law and Neuroscience" this year with two co-authors who are scientists from Vanderbilt University.
"There is a vast amount of memory science," said Shen, who has a law degree and a doctorate in government and social policy. He also did post-doctoral academic work in neuroscience. "The take-home point is something that memory science has known for some time and law has been slow to recognize: We have a lot more confidence in eyewitness testimony than we ought to have."
Said Hamline Law School associate dean Kate Kruse: "Eyewitness testimony is often extremely compelling evidence to a jury." Complicating that fact, she said, is that "even if the eyewitness is in fact mistaken, you're not usually dealing with someone who is lying."
Why? Here are some points from research: A memory is far from a videotaped version of an event; it is, rather, someone's personal experience of the event and may not be factually accurate. People may unwittingly change their memories to better fit in with the way other people are recounting an event. A strong suggestion from an authority figure, such as a police officer, can affect memory of an event. People sometimes say they remember things they haven't really experienced -- they just think they have. Merely retelling a story again and again -- as witnesses often do as they go through the court process -- can change the memory itself. A confident account is not necessarily an accurate account. Alcohol and drug use impair memories. And the passage of time can make a big difference.
Adding insult to injury, while a crime is being committed, eyewitnesses are likely to be subjected to factors that can negatively affect their memory of the event, such as stress, confusion, fear and surprise.
The Minnesota Innocence Project, an independent nonprofit organization housed at Hamline University in St. Paul, works with prisoners who say they're innocent.
The organization last month asked for a new trial for Billy Glaze, who was convicted of the rape and murder of three women in the 1980s in Minneapolis and has been in prison for 27 years. The conviction was in part a result of erroneous eyewitness reports, said managing attorney Julie Jonas, and Glaze should be exonerated on the basis of new DNA evidence.
A national study based on 316 exonerations has shown that 75 percent of the wrongful convictions were due to misidentification by an eyewitness.
Woodbury defense attorney Murad Mohammad said research shows some people have trouble telling apart people from other races or ethnic groups: "When you're asking somebody to identify from a community they don't interact with on a daily basis, that is a recipe for disaster."
The Innocence Project and others have used research to persuade law enforcement to change procedures for eyewitness identification, thereby reducing the chance for misidentification and strengthening the reliability of what eyewitnesses remember.
"The big step most of us prosecutors have taken is a double-blind photo array," said Washington County Attorney Pete Orput. It used to be, he said, that police would show a victim or witness a "six-pack," or six-photo sheet, and say, "Which one of these guys did it?" That assumes the criminal's photo is among the six, which, if the police haven't found the true culprit, it might not be.
The better way, Orput said, is to pass along a file of six individual photos to an officer who doesn't know which among them is the suspect; to tell the witness that it's possible the culprit is not among that batch of photos, and to have the witness look at the pictures one at a time.
Eyewitness identification isn't enough, though, Orput said. "I don't think I've ever tried a case where we had nothing but 'That's the guy who did it.' That makes us very nervous."
Even events that several people have seen end up with disparities among their memories, he said; one person would say he heard three shots, while another would say five shots, for example. And someone who is held up may remember only the appearance of the gun, not the person holding the weapon, he said.
Memory may be fallible, but even so, the court system needs to rely on it because what people say they saw and heard are the keys to the case.
"That's why it's so hard for jurors," said Diane Wiley, a founder of NJP Litigation Consulting Midwest in Minneapolis. "They have to listen to everybody and say, 'These stories are all different.' So what the jury has to do is look at the people who testified. And the first question, in a bar, would be, 'What state was the person in -- was the person drunk or somewhat inebriated?' And then they have to ask, 'Where were they in the bar?' And then they have to ask, 'Does this person have an agenda?'
"Ultimately, you do have to ask, 'Do I think this person is lying?' "