Chapter 1: What is the main topic discussed in this episode?
You're listening to TED Talks Daily, where we bring you new ideas to spark your curiosity every day. I'm your host, Elise Hu. What if eyewitness memory is more reliable than we've been told?
In this talk, psychologist and memory scientist John Wickstead shares new research that shows memory is more nuanced than we may think, and that ignoring it at the wrong moments can, and often does, put innocent people behind bars.
Drawing on real cases, he explains how a witness's first identification before, quote, memory contamination should not be overlooked and that it can offer remarkably reliable insight, potentially reshaping what we can and can't trust.
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% 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 gonna 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.
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Chapter 2: What if eyewitness memory is more reliable than we've been told?
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 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.
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Chapter 3: How can memory contamination lead to wrongful convictions?
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 them 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
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Chapter 4: What is the significance of the first identification in eyewitness testimony?
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 lineup 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 an obviously inconclusive identification full of doubt and indecision. by the time of his criminal trial.
After much memory contamination, better 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. All right, here's where the story takes another interesting turn. On this first test, using a photo lineup, witnesses often don't even tentatively identify the suspect the way that Jennifer Thompson tentatively identified Ronald Cotton.
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