Imagine for a moment that you're absolutely certain about the person you saw commit a crime. You're so confident, you'd be willing to testify about it under oath in a court of law. Your memory is strong, crystal clear, absolutely unshakable. But now imagine that that same memory, though it feels 100 percent true, is actually false and could send an innocent person to prison, maybe even to death row. This is the complex and sometimes heartbreaking world of eyewitness memory. But for decades, we've been telling ourselves a story about eyewitness memory that itself may not be entirely true. Most of you have probably heard cautionary tales about how wildly unreliable eyewitness testimony can be. You may have heard about famous cases like the case of Ronald Cotton, where Jennifer Thompson, a rape victim, misidentified him as her attacker. As she would later recall her testimony from his criminal trial, "I was absolutely, positively, without a doubt certain that he was the man who raped me when I got on that witness stand. And nobody was going to tell me any different." The jury understandably found her testimony convincing. Cotton was found guilty and sentenced to life in prison. But Ronald Cotton did not rape Jennifer Thompson. Instead, it was a known rapist prowling her neighborhood that night. Cotton spent almost 11 years in prison before DNA testing finally proved his innocence and revealed the identity of the true rapist, a man named Bobby Poole. Jennifer Thompson's testimony was sincere, but her memory was wrong. DNA exoneration cases just like this one, involving confident misidentifications, have happened literally hundreds of times, leading many to seriously question the reliability of eyewitness memory. But wrongful convictions like these are not the only reason why most people think eyewitness memory is unreliable. For years, scientific research has also painted a damning picture of human memory. Starting in the 1970s, scientists like Elizabeth Loftus began to show how shockingly easy it is to manipulate memory. In groundbreaking studies, she and others implanted false memories in adults of having been lost in a shopping mall as a child, or as having been attacked by a vicious animal, even though these things never actually happened. Findings like these seem to confirm our worst fears. Memories are not like video recordings. They're more like evidence from a crime scene, collected by people without gloves, distorting and contaminating it with every touch. This message from science reinforced the message from the wrongful convictions, and the conventional wisdom was set in stone for decades. The legal system should not trust eyewitness memory. It's just too unreliable.

But here's where the story takes an unexpected turn. What if the problem is not so much about how unreliable eyewitness memory is, because of how easily contamination can create false memories, and more about how and when we test the witness's memory. Think about forensic evidence like DNA or fingerprints. Everybody knows that forensic evidence can be contaminated and end up implicating an innocent person, much like contaminated memory can. But we don't just dismiss forensic evidence for that reason. Instead, we collect it as early as possible in the police investigation before it's contaminated. Why do we do that? It's because reliable information comes from analyzing uncontaminated evidence, not contaminated evidence. And the exact same principle applies to memory evidence. Collect it early, before it's contaminated.

An eyewitness’s memory of whether or not the police suspect is the person who they saw commit the crime can be highly reliable, but only if the witness's memory is uncontaminated, not after it's been contaminated. And scientists now agree that even the first test contaminates the witness's memory for a given suspect. If the suspect’s innocent, for example, it's the first time the witness is seeing his face, and this is happening at a time when the witness is actively thinking about the crime. So even if the witness says, "No, that's not the guy who did it," this is how the innocent suspect’s face first becomes associated with the crime in the witness's memory. That's contamination. You can’t keep that from happening, and you can’t put the witness’s memory back the way it was. So focus on the first uncontaminated memory test early in the police investigation, not the last, thoroughly contaminated test that happens at the criminal trial one, two, or even three years later. Unfortunately, courts tend to do the reverse, placing their faith in the last test of memory at trial while all but ignoring the critical first test. This is a seriously underappreciated problem. Well, with that in mind, let's take a closer look at how the police conduct that all-important first test of a witness’s uncontaminated memory. In the days or weeks after a crime, the police might find a suspect, a person who they think may have committed the crime, and they'd like to show him to the witness to see if they have the right guy. They could just hand the suspect's photo to the witness and ask, is this the guy who did it? The problem is, that would be suggestive, because it would reveal to the witness who the police think may have committed the crime. To test memory in a less suggestive way, the police will often show the witness a whole set of six photos. It's called a six-pack photo lineup. One photo is of the suspect, and the others are of similar-looking individuals who the police know are innocent. That way, they can still show the suspect's photo to the witness, but without revealing who they think committed the crime. It's a much fairer way to test memory, and it becomes fairer still when other recommended practices are followed. Such as letting the witness know that the perpetrator who they saw commit the crime may or may not be among these photos. And the officer who's administering these photos to the witness should not even know who the suspect is to avoid unintentionally influencing the witness’s choice. When it's done this way, it becomes a pure test of the witness's memory, and this is where things start to get interesting. About 10 years ago, work from my lab, published in strong, high-impact scientific journals, first reported that a confident identification of a suspect from an initial photo line-up is highly reliable. Big surprise. Not unreliable. For a scientific field that has spent decades cautioning the legal system about the unreliability of eyewitness memory, these findings were not easy to enthusiastically embrace. But almost all of the recent science finds that an initial, confident identification is much more reliable than the field previously thought. Not infallible, of course, but certainly not unreliable.

These new scientific findings raise an interesting question about the DNA exoneration cases that I told you about earlier. The ones where we know that on the last test of their memory, at the criminal trial, witnesses confidently misidentified an innocent person contributing to a wrongful conviction. The question is: What did those witnesses do the very first time their memory was tested for that same person? And when you look into that, you find they usually did not confidently misidentify the innocent suspect at that time. The problem is, nobody listened to them. Remember Jennifer Thompson? She struggled with the initial photo lineup a few days after the crime. Narrowing it down to two pictures, wavering hesitantly between them for literally minutes before finally landing on Ronald Cotton's face and saying, "I think it's him." It was obviously inconclusive identification, full of doubt and indecision. By the time of his criminal trial, after much memory contamination, that her doubts were gone and she became absolutely, positively, without a doubt certain that Ronald Cotton was the man who raped her. If they had known then what we know now, focus on the first test, where, in this case, you find a completely inconclusive identification, it seems likely that Ronald Cotton never would have been wrongfully convicted in the first place. And that's the point.

Yet many witnesses who reject an initial photo lineup, after their memory becomes contaminated, will show up at a criminal trial a year or two later, unaware that their memory is contaminated, and now confidently identify the very same person they initially rejected. Half the time, they don't even remember doing that, it was so long ago. These defendants are often convicted, sentenced to long prison terms, and are now behind bars. And unlike Ronald Cotton, they do not have any DNA evidence to prove their innocence. But what they do have is a new message from the world of memory science that can help to do that. And ironically, in a complete mind flip, it's reliable evidence of innocence from the memory of an eyewitness the first time they were tested. Consider the case of Miguel Solorio. He was arrested in 1998 for murder. But on the first test, four witnesses rejected his photo lineup. Nobody paid any attention to that. More than a year later, two of those same witnesses showed up at his criminal trial and identified him as the shooter in front of a judge and jury. He was convicted and sentenced to life in prison without the possibility of parole. Miguel spent 25 years of his life, from age 19 to age 44, behind bars, before finally being exonerated in late 2023, with the help of the new science that I'm telling you about today: focus on the first uncontaminated test. As tragic as Miguel's story is, at least the new science helped to overturn his conviction before he spent his entire life in prison. But others with a similar story remain behind bars as we speak. And some of them, their lives are hanging in the balance. Consider the case of Charles Don Flores. He, too, was arrested for murder in 1998. There was one witness in this case. On the day of the crime, she told the police that she saw a white male with shoulder-length hair go into her neighbor's house shortly before the murder occurred. A couple days later, she goes back to the police station. They hypnotize her. It's always dicey, but she stuck to her story. She said it's a white male with shoulder-length hair. The police asked her to make a composite sketch, so she did. Came out to be a white male with shoulder-length hair, just like she said. Now keep in mind, this is very early in the police investigation. This is a time when her memory of the perpetrator is as fresh and strong and uncontaminated as it will ever be. And this is what the perpetrator looks like. But the police suspected Charles Don Flores, a Hispanic man with short hair. And for some inexplicable reason, put his photo in a photo lineup and showed it to the witness. This is still early in the police investigation. This is the all-important first test of a witness's uncontaminated memory for the suspect, Charles Don Flores. The witness looked at this photo lineup, didn't see any white males with shoulder-length hair, and quite understandably rejected it, providing clear evidence that Flores is innocent. Fast forward to his criminal trial a year later, and you can probably guess how this story turns out. Now the witness is more than 100 percent certain that it was Charles Don Flores she saw go into her neighbor's house on the day of that murder. The jury was convinced, he was found guilty and sentenced to death. He's been on death row for more than 25 years, where he remains to this day. And in all those years, no jury even heard what the witness did on the first test of her uncontaminated memory, much less about the new scientific consensus, emphasizing the importance of focusing on that first test, because that's where the reliable information is.

So, you see, this isn't just an academic exercise. It's about exonerating the wrongfully convicted, some of whom are on death row, and about preventing wrongful convictions from happening in the first place. It's about understanding that memory is not an enemy to be distrusted, but a complex tool that, when properly used, can serve the cause of justice. The reforms that need to be made going forward seem pretty clear. Number one, in both police investigations and legal proceedings, prioritize the first test of the witness's uncontaminated memory, because that's where the reliable information is. Number two, at the same time, de-emphasize confident suspect identifications made by a witness who earlier rejected that same face because that likely reflects memory contamination, not the truth. And number three, to get these reforms underway, educate legal professionals, police chiefs, defense attorneys, prosecutors, judges about the new science of eyewitness memory. Over the last couple of years, my colleagues and I have been doing just that, reaching out to defense attorneys and prosecutors alike to bring this new understanding to the legal system. We find that initially, at least, defense attorneys are alarmed by this new message because they're uncomfortable with the idea that eyewitness memory can ever be reliable. To them, listening to what an eyewitness has to say, even on the very first test of their uncontaminated memory, is just a recipe for another wrongful conviction. And prosecutors, they're equally alarmed, but for the opposite reason. To them, not listening to a witness who makes a confident suspect identification after previously rejecting that same face sounds like a recipe for letting the guilty walk free. So we've managed to bring both sides of the aisle together in a way, to both the defense and the prosecution our new message sounds dangerous. But it's not dangerous. It's just how memory works. To better serve the cause of justice, both sides and all of us have to follow the science by listening to memory when it most reliably speaks the truth. It will become a more just world if we can find a way to do that. Thank you. (Applause)