Ep19 "How far can you trust your memory?"

Welcome to Inner Cosmos with me David Eagleman. I'm a neuroscientist and an author at Stanford and in these episodes we sail deeply into our three pound universe to understand the intersection between brains and our lives. Today's episode, we're going to be talking about eyewitness testimony. I think it's fair to say that most of us when we see something happen, we know what we've just seen. This occurred, this is what the person looked like, and so on.

And in fact, when jurors get interviewed on this point, they'll often say something like, yes, I understand there are problems with memory and eyewitness testimony, but my memory is like a video recorder. But the question we're going to ask today is how good is our memory really and what does that mean for courts of law? So strap in because we're going to see some amazing events and court cases that may change your opinion on your own

memory and about what you take to be true. One of the courses I teach it Anford is the Brain and the Law. It's where neuroscience intersects with the legal system. And a few months ago I was in the middle of lecturing to my seventies students when something very wild happened. I was talking to the auditorium and the back door opens, and a middle aged woman comes in at the back of the classroom, and she walks halfway down the aisle toward me and then just interrupts me, as though I

weren't talking at all. She says, are you David Eagleman? And I said yes, but I'm in the middle of teaching a class. Who are you? And she starts shouting how she's emailed me over and over and hasn't gotten any reply. So I said, I'm sorry, I have an overwhelmed inbox and I can't get to all my emails, but I am teaching a class and I'll have to

talk with you later. But she's clearly very agitated, and she doesn't leave, and she keeps shouting at me and takes a step closer to me down the aisle and asks if I'm ever planning to answer her, or whether I'm going to continue to ignore her. And I say, ma'am, you're going to have to leave and I'll talk with you afterwards. And finally, after what seemed like forever, although it was presumably less than a minute, she says, I'm going to wait for you out here, and she goes

stomping out the back door. So I tried to maintain normalcy, and I continued the lecture for about thirty more minutes. And this class is a long one. I give three hours of lecture, so normally at this point I give my students a break at the midpoint, where we go outside and we stretch for a few minutes. But I said to the class, look, it's our break time. But I'm not sure that it's going to make sense to go

out there. I'm going to call campus security just to let them know about that woman, and I want to give them a description, but I couldn't really tell her height and wait very well from up here at the podium, and I guess I was so caught up in the surprise of the whole thing and thinking about the ways this scenario could evolve badly that I didn't really encode all the details that I wanted to, like what she was wearing, or her hair color, or the details of her face as well as I wish that I had

encoded these. So I told the class, look, I remember the random fact that she had sunglasses perched on top of her head, but I would really like your help in getting a rich description. So I got everyone to take out a piece of notebook paper, and I told them the best way to accurately identify someone is to

have a collection of witnesses do this independently. So I said, look, if you could draw a picture of what she looked like and also write down her height and her weight, then I'm going to compile these and give Stanford Security an excellent description. So one thing I said is don't look at each other's drawing. Just drawn on your own and then hand it up to me. So everyone drew their best version of how they remembered her, and some people relied more on the drawing part and some on

the verbal descriptions. I collected these all up, and I said, great, I'm going to have a very complete average version of her that I can communicate to security. So I started flipping through these and reading them out loud to the class, and we were all shocked because one person described her as five foot four and wearing a blue shirt and the next described her as five foot eight and wearing

a white shirt. And the age estimates were between forty and sixty, and the hair color was everything from brown hair to gray hair to light hair and so on. And the body weight ranged over about forty pounds. So the whole collection provided me with no benefit at all in calling security. So I didn't call security, but not for the reason you might think. The reason I didn't call is because the woman was a professional actor that

I had hired. And the whole point of the exercise was to demonstrate firsthand to my students that vision is not like a camera and memory is not like a recorder. And from there I segued into the real topic of the lecture, which was on the problems and challenges of eyewitness testimony. So let's begin with a woman named Jennifer Thompson. She was twenty two and living in North Carolina, and

a man broke into her apartment and raped her. It was a long ordeal, and Jennifer really paid attention to his face so that she would be able to identify him later. When this whole terrible event was over and he ran off, she drove herself to the hospital and had a rape kit taken, and then she went straight to the police, and with their help she was able to create a composite image of what he looked like.

So the police went out and they gathered suspects, and they put together a lineup of seven men, and Jennifer concluded that one man in that lineup, a man named

Ronald Cotton, was the man who had raped her. So Cotton went to jail for the crime, but the whole time he was there he maintained his innocence, and many years into his jail sense he saw the oj Simpson trial on the prison television and he heard about DNA evidence, which was something he had never heard of before, and so he contacted his lawyer and he said, what is this DNA evidence? Is this something we should look into?

And his lawyer was able to get a hold of the rape kit from almost eleven years earlier, and they were able to extract enough DNA from that, and it turned out that Cotton was in fact innocent. He was not the man who had done it. The man who had raped Jennifer Thompson was a man named Bobby Poole, and he was then apprehended and confessed to the rape. And so Ronald Cotton was released after having spent eleven years of his life in prison for a crime he

did not commit. So Jennifer was shattered by this because she realized now that, based on her eyewitness testimony and her certainty, she had sent an innocent man to jail for eleven years. And she said that one of the most important things to her as a rape victim was to never feel any guilt over what had happened to her. It wasn't her fault that she had been raped, But all of a sudden, now she was crushed with guilt because she had ruined an innocent man's life by erroneously

identifying him in a lineup. So, about three years after Ronald Cotton got released, she decided she was going to reach out to him, make contact with him, and of course she was terrified about doing this. But she contacted him anyway, and they met at a church and he said that he had already forgiven her, and they talked at length, and they both cried, and eventually they became friends, and they ended up writing an excellent book together. It's

called Picking Cotton. And one of the things she does in the book is wrestle with the question that was most deeply burned into her mind. How could she have picked the wrong person and have felt so certain about it. How can one feel so sure and be wrong. So they travel around and give talks together about the fallibility of eyewitness testimony, about how you can believe one hundred percent that's the face, but it doesn't actually necessitate that you are correct. I met the two of them at

a conference when they were talking about the book. They're close friends now, and they travel around together so much that often people mistake them for a couple, and they say, oh, how did you two meet, And they say, it's a long story, okay. But the heart of the problem is that memory is always a reconstruction. Memory is not like

a videotape. It's not as though your memory is something where your visual system is taking in information and retaining zeros and ones the way a cell phone video would. All you ever see is what you believe you are seeing out there. So if I were to ask you the details of what's in front of you right now, you'd be able to answer it once you pay attention to things. But you weren't aware of that even though it's been sitting on your retina this whole time. You're

not actually seeing the world like a camera. Instead, what you have is a rough internal model of what's going on. And when you need to take in more information, then you do. You go out and point your eyes and pull in more in. So when I ask you about the scene in front of you, you need to employ your attentional mechanisms to go and crawl the scene out there and try to identify what's sitting there. So today's

question is how reliable is eyewitness testimony? In the courtroom, for my students, I was able to demonstrate to them the massive variety of their drawings tall, short, heavy, light, curly hair, straight hair, glasses, no glasses, and none of their drawings looked particularly like the actor at all. But forget a classroom test, how does this play out in the real world? How often does I witness testimony end up convicting the wrong person, as happened with Jennifer and

Ronald Well. One thing you could do is look at people who are found to be innocent years after they were convicted for a crime, and then figure out what percentage of them were convicted in whole or in part based on iwold testimony. So you may have heard of the Innocence Project. It is for people who are serving time in prison and are maintaining their innocence. The lawyers and forensic scientists at the Innocence Project go back and open these cold cases and work to reassess the case

with DNA evidence. So what the Innocence Project found out of the two hundred and forty people that they have exonerated, in other words, who have been found innocent of the crime they were convicted for, is that over sixty percent of them went to jail in whole or in part because of eyewitness testimony where someone said, I know that's the guy. I saw him with my own eyes. There's no doubt in my mind. Now this leads to a

question does eyewitness testimony matter? How swaying is it to jurors? Well, the answer is it's enormously swaying. The US Supreme Court Justice William Brennan pointed out that vote all the evidence points rather strikingly to the conclusion that there is almost nothing more convincing than a live human being who takes the stand, points a finger at the defendants and says,

that's the one unquote. So imagine you have a prosecutor showing circumstantial evidence, or a scientist comes up and says, look, here's my neuroimaging evidence, or you have a lie detector expert or whatever, and then you get an eyewitness and she takes the stand and she has tears in her eyes. She's genuine, she says, I know what I saw. He

is the one that has enormous way on jurors. Justice Brennan goes on to point out that eyewent his testimony is the type of evidence that quote, juries seem most receptive to and not inclined to discredit end quote. In other words, a scientist might say something on the stand and the jury thinks, yeah, maybe, but there's another interpretation. But when it comes to an eyewitness, we tend to say, Okay,

that's the gospel. Finally, Brennan points out that the court has long recognized, at least since the nineteen sixties, the quote inherently suspect qualities of eyewitness identification evidence unquote, and that the court finds that kind of evidence quote notoriously unreliable end quote. So that's Brennan, having spent a life on the bench, describing what he knows to be true. So why is it so swaying? Well, maybe we can

find some evidence from the laboratory. So my colleague, Elizabeth loftis that you see, Irvine is probably the most famous memory eyewitness researcher. Here's one example of her many many studies. You tell mock jurors the details of a case. They get to hear the attorneys on both sides, the prosecution and the defense, give their arguments. Some of the jurors only hear circumstantial evidence. There's no eyewitness testimony in that case.

And given the facts that they've heard, eighteen percent of the mock jurors conclude that the guy is guilty. But the other group, here's eyewitness testimony, everything else being the same, and now seventy two percent of the mock jurors find the guy guilty. So it goes from eighteen percent of people finding him guilty to seventy two percent just based

on the eyewitness testimony. That means that even though we know eyewitness testimony is inherently unreliable, just look at the effect of saying, we have someone who saw that person. Maybe it was a little bit far away, maybe it was sort of dark out, but I'm pretty sure that was the guy, and bam, it goes up to seventy two. It's a huge difference, And for something that's so unreliable, it's a little hard to justify that kind of pull. So we know that eyewitness testimony is swaying, But why

is it so bad? Why can't we look at somebody like the actor who broke into my classroom and just describe accurately what she looked like. Well, for starters, it's really really hard to remember what somebody looks like. Think about the last time you went to the coffee shop, what precisely did the person at the cash register look like? Or if you had to describe your neighbor down the street who you don't see that often to the police,

how well could you do so? If you really had to pull out a piece of paper and draw the face or describe it verbally. So police have worked for decades to try to make this easier. The original approach was to have a trained artist who sketches while you

and then you can work back and forth together. But eventually the police put together systems where you could just look at the individual features like the eyes and the eyebrows and the nose and the mouth, and you flip them until you get the face that you want out

of that. So instead of me asking you to take out a piece of notebook paper and draw seth Rogen, instead I say, look, here's a bunch of eyes and noses and mouths, and I want you to flip these around until you get a good picture of seth Rogen or the person that you saw or the perpetrator. So the first system for this was introduced in the late nineteen fifties by the Los Angeles Police Department. It was these features on transparent sheets and you rotate them around

and you reconstruct the face. This was called Identicit, and Identicate was used by Scotland Yard in a case in nineteen sixty one, a woman was stabbed to death in an antique shop where she work, and the police interviewed people and learned that someone suspicious had been in the shop a few days earlier, and so Scotland Yard turned to this invention from America and had their witnesses compile the suspect's face using identicit, And some days later a

policeman saw a man named Edwin Bush on the street and recognized him from the identicate pictures in the newspaper, and in fact, when they arrested him and took him to the station, they found he had a copy of the newspaper drawing in his own pocket, and his shoes matched the size of the shoes in the crime scene, and so on, and he ended up confessing to the murder.

So this was considered a real success in how you could crank up the reliability of identifying people and identic It was eventually replaced by photo fit in the nineteen seventies, where instead of using drawings, you use collages of photos of eyes and ears and noses and mouth and hairline and so on, and the photos give a better image

of the suspect's face rather than the line drawings. And with due course all this evolved into software in which you take a three dimensional model of the head and you do the same sort of thing where you can change the eyes and nose and mouth and eyebrows and so on. And there were many stories that came out of all these systems and that increased confidence in the approach.

But it turns out that despite success stories with this, when you really start looking into it, it turns out these face recognition approaches are generally not so good in terms of being able to identify people. Some years ago, an MIT researcher named Pawan Sinha got a hold of the standard facial software that police forces use, and he requested an expert with several years of experience with the system to put together reconstructions directly from a picture and

without time constraints. That meant the operator didn't have to rely on verbal descriptions. He could just look at the photos and put this together. So each year in my class, I show the students these four photographs and I offer ten dollars to whoever can identify the pictures, and no one ever can. There are lots of wrong guesses, but so far no one has gotten them. Right. Now, the pictures are of Bill Cosby, Carl Sagan, Ronald Reagan, Michael Jordan.

Now I get it. These are faces that the younger generation can't necessarily identify anyway. But at the peak of these guys popularity in the nineteen eighties, people couldn't identify these pictures. Then the reconstructions just weren't close enough to

the actual face to make the match. And in case you think this might just be a laboratory artifact, there are plenty of real life cases where you look at the identicate composite and then you look at the captured person's photograph and you'll know right away that you would have never identified that person from that drawing. Why. Well, part of the problem is that the feature based composite

image is built from the pieces and parts. You say, I think the guy's eyes looked sort of like this, and his mouth looked sort of like that, and his nose and his eyebrows and so on. But that's not the way the human visual system works. It recognizes faces based on the whole picture. What's called the gestalt, which is the German word that signifies when a whole is perceived as more than the sum of its parts. But

that is only one problem. Let's imagine that you could somehow reconstruct a pretty good likeness there's also the problem of similarity, which is to say, a lot of people just look alike. So there was an amazing case some years ago in which a man named Lawrence Berson, who had curly hair and big square glasses, was convicted of

several rape cases and went to jail. And then another guy, George Morales, with curly hair and big square glasses, was convicted of several robberies and went to jail, and both protested their innocence, and it turns out they were telling the truth. The guy who did all of the crimes was a guy named Richard Carbone, who had curly hair and big square glasses. Carbone had been described by several eyewitnesses, and these two other poor guys served jail time because

they were picked out of the police lineups. And putting a photo of these guys on eagleman dot com slash podcast because it's so striking how different people can look similar to one another. So I've told you so far that the brain in codes faces holistically, not in bits and parts, and also that a lot of people look roughly similar. But neither of those problems even competes with the biggest problem of eyewitness testimony, and that is our

memories are terrible. We all like to think that we can remember a face in describe it, but as my students saw from trying to draw the woman who broke into my classroom and spoke angrily with me for a minute, it's really hard to remember the details of someone's face and then try to reconstruct that. And the past few decades have seen really great studies which undermine our confidence that this should be easy to do. So the first thing to appreciate is that there are two phases of memory.

The first is encoding, So when the woman burst into my classroom, the students were encoding what they were seeing. Their brains were writing it down, and the second phase is retrieval, or pulling the memory back up later. In the case of my classroom, I waited about thirty minutes before asking them to draw the face, and it turns out the forgetting curve is quite steep. By thirty minutes in, they've forgotten most of the important details. So let's break

these down one at a time. We'll start with encoding, writing down the memory. One of the biggest problems with encoding a memory during a crime is what's called weapon focus. So if a person has a knife on you, or is wielding a gun, or has a baseball bat or whatever, your brain can't help but to be focused on that, and as a result, it's harder to remember details about the person's face. So here's another study from Elizabeth loftis she has you come into a room and she tells

you you're going to participate in some psychology exam. And while you're waiting there, you hear two people arguing, and then one person comes out of the room and he's got some grease on his hands and he's holding a pen. So that scenario one. Scenario two is to hear the same thing, the two people arguing, and then the guy comes out and he's holding a blood stained knife. And then she studies how well you can identify the person after that, And you can imagine what happens when the

guy is holding the blood stained knife. How good is your identification about what his face looked like. It's terrible. When there's a weapon involved, witnesses are not encoding the details about the person. They have high anxiety and they're staring at the weapon. It's the most salient thing in the scene. It is the ball to keep your eye on, so weapon focus is one problem. A second problem with encoding memory during a crime scene is what is called

Q overload. When there's a really salient scene going on, when there's lots of stuff happening, it's just hard to encode all of that. So let's say that the woman had come into my classroom and she was not only yelling at me, but she starts throwing something at me. And then as soon as that happens, I pull out a taser and then a student over on the left starts screaming, and suddenly a student on the right leaps up and says, I'm going to protect doctor Eagleman and

dives in to tackle her. Imagine, all this stuff is happening, bang bang bang, Well, it's really hard to encode all that because there's just too much going on at the same time, too many salient events happening at once. That's the Q overload effect. A third problem with encoding memory has to do with what's called the other race effect. We're much better at encoding faces of people who look like us, but for people who look different, it's harder

to catch the important details. Now, just to be clear, this isn't racism. It's not that you're discriminating against a group. The issue here is that the neurons in your visual cortex just aren't trained up on the details of those faces. It's a matter of what type of faces your brain knows well. In other words, depending on where you've grown up, you might have a difficult time making an accurate identification if you were shown a lineup of Cambodians or Icelanders,

or mauor or Wigers or Inuits. It's not that you have anything against these cultures. It's that you've grown training your visual system on the faces particular to your culture, whatever that is, and now you're dealing with measurements that are all a little bit different, like the intraocular distance and the nose length and the frenulum and the chin shape and so on. And if that's not where your experience and expertise lies, you're going to be worse at it.

So the other race effect often leaves eyewitness identification hobbled. And the fourth problem with encoding memories is that it often just performs worse when there's stress and trauma. During an event, something really awful and unexpected happens and it's simply not even part of what your world model thinks is a possibility, and so your brain has a difficult

time encoding what the heck just happened. So these are all problems with encoding the memory in the first place, weapon focus, Q overload, other race effect, stress and trauma during the event. Now, encoding is only half the game, because retrieval is the other half. So let's say you've written down some sort of rough memory of the woman who came into the classroom. She's somewhere between five three

and five nine. Okay, you encoded that sort of, but now there are problems with the retrieval of the memory, pulling up what was there in your brain. One problem is what's called the misinformation effect. If you're told something about a crime in terms of what happened at the scene, or who was there or what they looked like, that will become part of your memory and you may not

be able to distinguish that from what actually happened. So Elizabeth Loftus and others have studied this by showing people a picture of a car to stop sign, and then afterwards, after after the picture is gone, they give a text description of the same picture, but in the text they say it was a yield sign. And then they have people draw the picture as they remember it, and they draw the original scene but with a yield sign. So

they're told something after the memory was encoded. They're told that it was a yield sign, and when they're retrieving the memory, they believe that the whole time they saw the yield sign there instead of the stop sign. In the case of my classroom invader, you may remember that I told the students that I remembered the woman had sunglasses on top of her head. Well, she didn't have

sunglasses on her head. I made up that fact and I asserted it, and a number of students incorporated that false item into their memory what they think they saw, and afterwards they felt certain that that was a part of their original memory. Now that might sound crazy, because you think I could distinguish my own memory from something someone else said, but it turns out you often can't. So misinformation after the fact is one problem that happens

with retrieval. A second problem is what's known as unconscious transference. Now to explain this, I'm going to tell you an absolutely incredible true story. There's a British psychologist named Donald Thompson, and one evening he went on British television to talk about eyewitness testimony and memory. Unbeknownst to him, while he was on live television, a woman in England had her

apartment broken into and she was raped. She went to the police and described Donald Thompson and had his face drawn. She insisted this was her rapist. He was arrested the next day, but he said, I have a watertight alibi, which is that I was in a live television studio sitting with the police commissioner. And it took a little bit of time for all this to get worked out

and unraveled. But of course his alley was verifiable. What happened was he was on the television set she was getting raped, and she transferred her memory of the rapist's face to his face. She got confused about whose face was who. It's such a crazy irony that he is a memory expert, because it could have been anybody on

the television, but there it is incredible but true. So unconscious transference is a problem where a victim can't distinguish between the perpetrator of a crime and some other face that they saw in the same context or a totally different context. So those are some of the problems with memory retrieval. And one of the places where these problems come up all the time is in the police lineup. So imagine that you are presented a lineup with several people and you have to make a choice about which

person you saw doing the crime. Well, one of the things that started getting recognized in the nineteen sixties and went to the Supreme Court was the idea of police suggestibility. It turns out that if the police already have their man in mind, they already think it's Fred. Whether or not that's correct, they believe it's Fred, and they want you to say it's Fred. There are all kinds of ways that they can suggest that to you, including just

things like positive feedback. So if you say I think that was the guy, they'll say, yeah, good job, that's what we think also, And it turns out that influences the confidence of the eyewitness. When the trial starts months later, you'll say I'm absolutely certain that it was Fred, even though you might not remember that you weren't certain at all, But because of the positive feedback, which can even be quite subtle, like you know, just a nod or a

smile or whatever, your confidence goes way up. And thirty years of psychology studies in the laboratory have verified the power of this suggestibility. As a result, psychologists have made suggestions to police forces and this has spun all the way up to the Supreme Court, with the result that police are not allowed to have any suggestibility involved. One of the ways to take care of this is to

make the lineup identification double blind. That means the police officer who is running the lineup doesn't even know who the main suspect is. And this way the person doing the identifying gets no feedback at all. And by the way, the main thing that everyone's worried about with lineups is false identification. If the perpetrator is in the lineup and you miss him, that's another kind of problem. But the really terrible problem is sending an innocent person to prison

with the false belief that you have identified him. I'll give you another problem that psychologists and legal theorists have studied, and that's the issue of co witness contamination. The idea is that if you see a crime and I'm standing there and I see it too, and then we start talking about it with one another, we can't help but influence each other's memories. This is a close relative of

the misinformation problem. If you remember that she had curly hair, but I say I'm pretty sure she had straight hair. Or if you think she was unathletic and I say, no, she was quite athletic, both our memories become contaminated by the other one statement, and we more and more come to believe things that we didn't originally. So one thing that police know to do straight away is to separate witnesses.

And there are many many aspects that have come from research that are now built into the way that police optimally do lineups. For example, they try to make sure that you don't see photographs of a suspect before the lineup, because if you do, you're really likely to identify that guy. One place this comes up is contamination by photos in

news stories. So CNN says the suspect looks like this, and then you're brought into a lineup, and whether or not you remember having seen that story on CNN, that influences your performance in the lineup. So many guidelines have come out of this research. I'll give you just a few examples. One guideline is to make sure that the eyewitness is aware that the perpetrator might not be in

the lineup. Another is this double blind procedure that I mentioned that doesn't allow police to see the lineup, so they can't subject to the eyewitness to any of their suspicions as to who the suspect is, and courts are increasingly recognizing that this speed of recognition matters. Generally speaking, if the witness quickly identifies the perpetrator, then the selection

is more likely to be correct. Finally, if the appearance of a person stands out amongst the otherwise undistinctive crowd, then an eyewitness is more likely to select that person, regardless of their own recollection of the criminal. This is known as the distractor or dud effect. So there are many places where scientific study has made d contributions to

the optimal way to run. I witnessed identification procedures. Now what if somebody comes in and they say, I saw the guy, and I know with one hundred percent certainty that was the guy, Versus someone else who comes in and says, I don't know, I was looking out a window. It was a car robbery going on two stories below me. It was kind of dark. I couldn't really see him very well. I think that was the guy. I don't really know. Do you think those two scenarios should be

treated differently? In other words, what is the relationship between confidence and accuracy? Well? The United States Supreme Court had to answer this question in nineteen seventy two in a case called Neil versus Biggers. What happened was that the victim, Margaret Beemer, was dragged into the woods and assaulted. She described her attacker to the police only in very general terms.

Then she was shown a bunch of photographs and people who met the description, but she couldn't identify anyone from the photos or stand ups for seven months. So the police then get a guy on another charge, a got named Archie Biggers, and they decide to include him in a stand up, But they couldn't find anyone who made a good match to this guy's looks, so they did what's called a show up instead, where there's no one

else there but the one suspect. So two detectives walk Biggers passed the victim, and at her request, the police directed him to say shut up or I will kill you. The testimony a trial wasn't clear as to whether she had first identified him and then asked that he repeat

those words, or made her identification after he'd spoken. In any event, the victim testified that she had no doubt about her identification, and so Biggers was convicted, and he came back on appeal and argued it simply wasn't fair, this was unreliable. The lower courts agreed with him and said, no way, We're not accepting this as evidence because this identification process was extremely suggestive. But the US Supreme Court

eventually heard this case and reversed that decision. They concluded it was okay why because she said that she was certain. In other words, they concluded that how confident a person is relates to how good their evidence is. They felt that high confidence allows you to judge the veracity of a witness. So, in other words, the Supreme Court said implicitly that they think there is a relationship between confidence and accuracy. But generally, cognitive psychologists find that this relationship

is very weak. Because of all the things we've talked about in this episode. Confidence does not work as a yardstick of accuracy, especially as time goes on and I'm going to do an episode soon about how the legal system decides which technologies to allow into their courtrooms, But for now, I'm just going to point out that it requires passing high scientific standards. So how do you think

eyewitness testimony compares well? A version of this question hit the US Supreme Court in twenty eleven Perry versus New Hampshire. I spoke with Sanjay Gupta on CNN about this case when it was getting decided. The question the court was asking was essentially, if there's lousy eyewitness testimony in a case, should it be allowed? When does that violate the right

to do process? You'll write to a fair trial. So Perry was a young man in New Hampshire who got convicted of stealing a car, and he was convicted based in large part on a woman who was looking out a second story window in the dark. She couldn't see well from that distance. So Perry got convicted in a New Hampshire court, and they came back and tried to appeal, and he said, how can you possibly take this woman's word for it? How could you send me to jail

based on such unreliable witness testimony? The lower courts upheld the decision, and so this question spun up to the US Supreme Court. The question that was on the table is does unreliable eyewitness testimony violate your constitutional rights? And what the court said is, look, the only thing we care about is whether there was suggestibility by the police. If the police manipulated the process, then the due process clause of the Constitution is applicable. But they said, this

does not hold generally for eyewinness testimony. Using unreliable evidence against you is not unconstitutional. There's no right that you'll have great evidence. Instead, it's the job of the jury to figure it out, to weigh the evidence. So that's

what the court decided. And reading between the lines, what do you think one of the concerns of the court was here, It's this, if you introduce a question about the reliability of the witness, then you would, in theory, require a pre trial hearing to determine if her testimony is acceptable or not. And what does that do to every single case running in the nation. One of these

Supreme Court justices posed this during the case. He said, what about jailhouse testimony where someone in the jail says, my cellmate told me x Y and Z. Sometimes it's unreliable, sometimes it yields fruit. Do we require a pre trial hearing every time because it might not be reliable? So this is an issue that would overturn the way the whole court system works. And so, at least for the time being, the legal system knows that eyewitness testimony is terrible.

It can be very unreliable, and yet with all the caveats, there's no choice but to let it remain. So in closing your memory is not necessarily what you think it is. Memory is not writing down what happened in zeros and ones and then reading that back out. There are many things that get in the way of good encoding and retrieval.

I really recommend Jennifer Thompson and Ronald Cotton's book. For Jennifer, this was a complete pouring out of her guts on the table a cathartic enterprise where she had to allow that she put a man in jail for eleven years based on her certainty that that was the face she had looked into. She knew it was Ronald Cotton, and she wanted him to die. That's how she felt about this man. And then she found out that she was wrong.

So the book is about what it's like from the inside to believe, you know, and all the steps that happened along the way that manipulated her memory. So to summarize what we talked about today, eyewitness testimony has a terrific sway on jurors, and yet it is variable in its accuracy. Now, just for clarity, it's not that eyewitness testimony always has to be wrong. Plenty of times someone IDs someone and it's correct. But memory is not like a video camera. It is a reconstruction, and many factors

worse than the encoding and manipulate the retrieval. As a result, we cannot say that confidence and accuracy are tightly linked, especially as time goes on. Eyewitness testimony is not going away from the courtroom because often it's the only evidence that we can bring to bear in a case. So, even though it may be the worst technology that we allow in the courtrooms, it is presumably here to stay.

But remember, like much about our perception of the world that I'll be discussing throughout these episodes, just because you believe something to be true doesn't necessitate that it is. Go to Eagleman dot Com, Slash podcast for more information and to find further readings and to see some photographs. Send me in email at podcasts at eagleman dot com with questions or discussion, and I'll be making an episode

soon in which I address those. Until next time, I'm Dave Eagleman, and this is Inner Cosmos