Speaker 1: When you witness an event, when you see it with
Speaker 1: your own eyes, it certainly feels like what you saw
Speaker 1: can't be questioned. But how good is your memory? Really?
Speaker 1: Can you misremember details? Is your memory like a video
Speaker 1: or isn't it? Is your ability to remember changed by
Speaker 1: how many things are going on in the scene, or
Speaker 1: whether there's a gun pointed at you. Can something told
Speaker 1: to you after the event change your memory of the event.
Speaker 1: Welcome to Inner Cosmos with me David Eagleman. I'm a
Speaker 1: neuroscientist and an author at Stanford and in these episodes
Speaker 1: we sail deeply into our three pound universe to understand
Speaker 1: the intersection between brains and our lives. Today's episode, we're
Speaker 1: going to be talking about eyewitness testimony. I think it's
Speaker 1: fair to say that most of us when we see
Speaker 1: something happen, we know what we've just seen. This occurred,
Speaker 1: this is what the person looked like, and so on.
Speaker 1: And in fact, when jurors get interviewed on this point,
Speaker 1: they'll often say something like, yes, I understand there are
Speaker 1: problems with memory and eyewitness testimony, but my memory is
Speaker 1: like a video recorder. But the question we're going to
Speaker 1: ask today is how good is our memory really and
Speaker 1: what does that mean for courts of law? So strap
Speaker 1: in because we're going to see some amazing events and
Speaker 1: court cases that may change your opinion on your own
Speaker 1: memory and about what you take to be true. One
Speaker 1: of the courses I teach it Anford is the Brain and
Speaker 1: the Law. It's where neuroscience intersects with the legal system.
Speaker 1: And a few months ago I was in the middle
Speaker 1: of lecturing to my seventies students when something very wild happened.
Speaker 1: I was talking to the auditorium and the back door opens,
Speaker 1: and a middle aged woman comes in at the back
Speaker 1: of the classroom, and she walks halfway down the aisle
Speaker 1: toward me and then just interrupts me, as though I
Speaker 1: weren't talking at all. She says, are you David Eagleman?
Speaker 1: And I said yes, but I'm in the middle of
Speaker 1: teaching a class. Who are you? And she starts shouting
Speaker 1: how she's emailed me over and over and hasn't gotten
Speaker 1: any reply. So I said, I'm sorry, I have an
Speaker 1: overwhelmed inbox and I can't get to all my emails,
Speaker 1: but I am teaching a class and I'll have to
Speaker 1: talk with you later. But she's clearly very agitated, and
Speaker 1: she doesn't leave, and she keeps shouting at me and
Speaker 1: takes a step closer to me down the aisle and
Speaker 1: asks if I'm ever planning to answer her, or whether
Speaker 1: I'm going to continue to ignore her. And I say, ma'am,
Speaker 1: you're going to have to leave and I'll talk with
Speaker 1: you afterwards. And finally, after what seemed like forever, although
Speaker 1: it was presumably less than a minute, she says, I'm
Speaker 1: going to wait for you out here, and she goes
Speaker 1: stomping out the back door. So I tried to maintain normalcy,
Speaker 1: and I continued the lecture for about thirty more minutes.
Speaker 1: And this class is a long one. I give three
Speaker 1: hours of lecture, so normally at this point I give
Speaker 1: my students a break at the midpoint, where we go
Speaker 1: outside and we stretch for a few minutes. But I said
Speaker 1: to the class, look, it's our break time. But I'm
Speaker 1: not sure that it's going to make sense to go
Speaker 1: out there. I'm going to call campus security just to
Speaker 1: let them know about that woman, and I want to
Speaker 1: give them a description, but I couldn't really tell her
Speaker 1: height and wait very well from up here at the podium,
Speaker 1: and I guess I was so caught up in the
Speaker 1: surprise of the whole thing and thinking about the ways
Speaker 1: this scenario could evolve badly that I didn't really encode
Speaker 1: all the details that I wanted to, like what she
Speaker 1: was wearing, or her hair color, or the details of
Speaker 1: her face as well as I wish that I had
Speaker 1: encoded these. So I told the class, look, I remember
Speaker 1: the random fact that she had sunglasses perched on top
Speaker 1: of her head, but I would really like your help
Speaker 1: in getting a rich description. So I got everyone to
Speaker 1: take out a piece of notebook paper, and I told
Speaker 1: them the best way to accurately identify someone is to
Speaker 1: have a collection of witnesses do this independently. So I said, look,
Speaker 1: if you could draw a picture of what she looked
Speaker 1: like and also write down her height and her weight,
Speaker 1: then I'm going to compile these and give Stanford Security
Speaker 1: an excellent description. So one thing I said is don't
Speaker 1: look at each other's drawing. Just drawn on your own
Speaker 1: and then hand it up to me. So everyone drew
Speaker 1: their best version of how they remembered her, and some
Speaker 1: people relied more on the drawing part and some on
Speaker 1: the verbal descriptions. I collected these all up, and I said, great,
Speaker 1: I'm going to have a very complete average version of
Speaker 1: her that I can communicate to security. So I started
Speaker 1: flipping through these and reading them out loud to the class,
Speaker 1: and we were all shocked because one person described her
Speaker 1: as five foot four and wearing a blue shirt and
Speaker 1: the next described her as five foot eight and wearing
Speaker 1: a white shirt. And the age estimates were between forty
Speaker 1: and sixty, and the hair color was everything from brown
Speaker 1: hair to gray hair to light hair and so on.
Speaker 1: And the body weight ranged over about forty pounds. So
Speaker 1: the whole collection provided me with no benefit at all
Speaker 1: in calling security. So I didn't call security, but not
Speaker 1: for the reason you might think. The reason I didn't
Speaker 1: call is because the woman was a professional actor that
Speaker 1: I had hired. And the whole point of the exercise
Speaker 1: was to demonstrate firsthand to my students that vision is
Speaker 1: not like a camera and memory is not like a recorder.
Speaker 1: And from there I segued into the real topic of
Speaker 1: the lecture, which was on the problems and challenges of
Speaker 1: eyewitness testimony. So let's begin with a woman named Jennifer Thompson.
Speaker 1: She was twenty two and living in North Carolina, and
Speaker 1: a man broke into her apartment and raped her. It
Speaker 1: was a long ordeal, and Jennifer really paid attention to
Speaker 1: his face so that she would be able to identify
Speaker 1: him later. When this whole terrible event was over and
Speaker 1: he ran off, she drove herself to the hospital and
Speaker 1: had a rape kit taken, and then she went straight
Speaker 1: to the police, and with their help she was able
Speaker 1: to create a composite image of what he looked like.
Speaker 1: So the police went out and they gathered suspects, and
Speaker 1: they put together a lineup of seven men, and Jennifer
Speaker 1: concluded that one man in that lineup, a man named
Speaker 1: Ronald Cotton, was the man who had raped her. So
Speaker 1: Cotton went to jail for the crime, but the whole
Speaker 1: time he was there he maintained his innocence, and many
Speaker 1: years into his jail sense he saw the oj Simpson
Speaker 1: trial on the prison television and he heard about DNA evidence,
Speaker 1: which was something he had never heard of before, and
Speaker 1: so he contacted his lawyer and he said, what is
Speaker 1: this DNA evidence? Is this something we should look into?
Speaker 1: And his lawyer was able to get a hold of
Speaker 1: the rape kit from almost eleven years earlier, and they
Speaker 1: were able to extract enough DNA from that, and it
Speaker 1: turned out that Cotton was in fact innocent. He was
Speaker 1: not the man who had done it. The man who
Speaker 1: had raped Jennifer Thompson was a man named Bobby Poole,
Speaker 1: and he was then apprehended and confessed to the rape.
Speaker 1: And so Ronald Cotton was released after having spent eleven
Speaker 1: years of his life in prison for a crime he
Speaker 1: did not commit. So Jennifer was shattered by this because
Speaker 1: she realized now that, based on her eyewitness testimony and
Speaker 1: her certainty, she had sent an innocent man to jail
Speaker 1: for eleven years. And she said that one of the
Speaker 1: most important things to her as a rape victim was
Speaker 1: to never feel any guilt over what had happened to her.
Speaker 1: It wasn't her fault that she had been raped, But
Speaker 1: all of a sudden, now she was crushed with guilt
Speaker 1: because she had ruined an innocent man's life by erroneously
Speaker 1: identifying him in a lineup. So, about three years after
Speaker 1: Ronald Cotton got released, she decided she was going to
Speaker 1: reach out to him, make contact with him, and of
Speaker 1: course she was terrified about doing this. But she contacted
Speaker 1: him anyway, and they met at a church and he
Speaker 1: said that he had already forgiven her, and they talked
Speaker 1: at length, and they both cried, and eventually they became friends,
Speaker 1: and they ended up writing an excellent book together. It's
Speaker 1: called Picking Cotton. And one of the things she does
Speaker 1: in the book is wrestle with the question that was
Speaker 1: most deeply burned into her mind. How could she have
Speaker 1: picked the wrong person and have felt so certain about it.
Speaker 1: How can one feel so sure and be wrong. So
Speaker 1: they travel around and give talks together about the fallibility
Speaker 1: of eyewitness testimony, about how you can believe one hundred
Speaker 1: percent that's the face, but it doesn't actually necessitate that
Speaker 1: you are correct. I met the two of them at
Speaker 1: a conference when they were talking about the book. They're
Speaker 1: close friends now, and they travel around together so much
Speaker 1: that often people mistake them for a couple, and they say, oh,
Speaker 1: how did you two meet, And they say, it's a
Speaker 1: long story, okay. But the heart of the problem is
Speaker 1: that memory is always a reconstruction. Memory is not like
Speaker 1: a videotape. It's not as though your memory is something
Speaker 1: where your visual system is taking in information and retaining
Speaker 1: zeros and ones the way a cell phone video would.
Speaker 1: All you ever see is what you believe you are
Speaker 1: seeing out there. So if I were to ask you
Speaker 1: the details of what's in front of you right now,
Speaker 1: you'd be able to answer it once you pay attention
Speaker 1: to things. But you weren't aware of that even though
Speaker 1: it's been sitting on your retina this whole time. You're
Speaker 1: not actually seeing the world like a camera. Instead, what
Speaker 1: you have is a rough internal model of what's going on.
Speaker 1: And when you need to take in more information, then
Speaker 1: you do. You go out and point your eyes and
Speaker 1: pull in more in. So when I ask you about
Speaker 1: the scene in front of you, you need to employ
Speaker 1: your attentional mechanisms to go and crawl the scene out
Speaker 1: there and try to identify what's sitting there. So today's
Speaker 1: question is how reliable is eyewitness testimony? In the courtroom,
Speaker 1: for my students, I was able to demonstrate to them
Speaker 1: the massive variety of their drawings tall, short, heavy, light,
Speaker 1: curly hair, straight hair, glasses, no glasses, and none of
Speaker 1: their drawings looked particularly like the actor at all. But
Speaker 1: forget a classroom test, how does this play out in
Speaker 1: the real world? How often does I witness testimony end
Speaker 1: up convicting the wrong person, as happened with Jennifer and
Speaker 1: Ronald Well. One thing you could do is look at
Speaker 1: people who are found to be innocent years after they
Speaker 1: were convicted for a crime, and then figure out what
Speaker 1: percentage of them were convicted in whole or in part
Speaker 1: based on iwold testimony. So you may have heard of
Speaker 1: the Innocence Project. It is for people who are serving
Speaker 1: time in prison and are maintaining their innocence. The lawyers
Speaker 1: and forensic scientists at the Innocence Project go back and
Speaker 1: open these cold cases and work to reassess the case
Speaker 1: with DNA evidence. So what the Innocence Project found out
Speaker 1: of the two hundred and forty people that they have exonerated,
Speaker 1: in other words, who have been found innocent of the
Speaker 1: crime they were convicted for, is that over sixty percent
Speaker 1: of them went to jail in whole or in part
Speaker 1: because of eyewitness testimony where someone said, I know that's
Speaker 1: the guy. I saw him with my own eyes. There's
Speaker 1: no doubt in my mind. Now this leads to a
Speaker 1: question does eyewitness testimony matter? How swaying is it to jurors? Well,
Speaker 1: the answer is it's enormously swaying. The US Supreme Court
Speaker 1: Justice William Brennan pointed out that vote all the evidence
Speaker 1: points rather strikingly to the conclusion that there is almost
Speaker 1: nothing more convincing than a live human being who takes
Speaker 1: the stand, points a finger at the defendants and says,
Speaker 1: that's the one unquote. So imagine you have a prosecutor
Speaker 1: showing circumstantial evidence, or a scientist comes up and says, look,
Speaker 1: here's my neuroimaging evidence, or you have a lie detector
Speaker 1: expert or whatever, and then you get an eyewitness and
Speaker 1: she takes the stand and she has tears in her eyes.
Speaker 1: She's genuine, she says, I know what I saw. He
Speaker 1: is the one that has enormous way on jurors. Justice
Speaker 1: Brennan goes on to point out that eyewent his testimony
Speaker 1: is the type of evidence that quote, juries seem most
Speaker 1: receptive to and not inclined to discredit end quote. In
Speaker 1: other words, a scientist might say something on the stand
Speaker 1: and the jury thinks, yeah, maybe, but there's another interpretation.
Speaker 1: But when it comes to an eyewitness, we tend to say, Okay,
Speaker 1: that's the gospel. Finally, Brennan points out that the court
Speaker 1: has long recognized, at least since the nineteen sixties, the
Speaker 1: quote inherently suspect qualities of eyewitness identification evidence unquote, and
Speaker 1: that the court finds that kind of evidence quote notoriously
Speaker 1: unreliable end quote. So that's Brennan, having spent a life
Speaker 1: on the bench, describing what he knows to be true.
Speaker 1: So why is it so swaying? Well, maybe we can
Speaker 1: find some evidence from the laboratory. So my colleague, Elizabeth
Speaker 1: loftis that you see, Irvine is probably the most famous
Speaker 1: memory eyewitness researcher. Here's one example of her many many studies.
Speaker 1: You tell mock jurors the details of a case. They
Speaker 1: get to hear the attorneys on both sides, the prosecution
Speaker 1: and the defense, give their arguments. Some of the jurors
Speaker 1: only hear circumstantial evidence. There's no eyewitness testimony in that case.
Speaker 1: And given the facts that they've heard, eighteen percent of
Speaker 1: the mock jurors conclude that the guy is guilty. But
Speaker 1: the other group, here's eyewitness testimony, everything else being the same,
Speaker 1: and now seventy two percent of the mock jurors find
Speaker 1: the guy guilty. So it goes from eighteen percent of
Speaker 1: people finding him guilty to seventy two percent just based
Speaker 1: on the eyewitness testimony. That means that even though we
Speaker 1: know eyewitness testimony is inherently unreliable, just look at the
Speaker 1: effect of saying, we have someone who saw that person.
Speaker 1: Maybe it was a little bit far away, maybe it
Speaker 1: was sort of dark out, but I'm pretty sure that
Speaker 1: was the guy, and bam, it goes up to seventy two.
Speaker 1: It's a huge difference, And for something that's so unreliable,
Speaker 1: it's a little hard to justify that kind of pull.
Speaker 1: So we know that eyewitness testimony is swaying, But why
Speaker 1: is it so bad? Why can't we look at somebody
Speaker 1: like the actor who broke into my classroom and just
Speaker 1: describe accurately what she looked like. Well, for starters, it's
Speaker 1: really really hard to remember what somebody looks like. Think
Speaker 1: about the last time you went to the coffee shop,
Speaker 1: what precisely did the person at the cash register look like?
Speaker 1: Or if you had to describe your neighbor down the
Speaker 1: street who you don't see that often to the police,
Speaker 1: how well could you do so? If you really had
Speaker 1: to pull out a piece of paper and draw the
Speaker 1: face or describe it verbally. So police have worked for
Speaker 1: decades to try to make this easier. The original approach
Speaker 1: was to have a trained artist who sketches while you
Speaker 1: and then you can work back and forth together. But
Speaker 1: eventually the police put together systems where you could just
Speaker 1: look at the individual features like the eyes and the
Speaker 1: eyebrows and the nose and the mouth, and you flip
Speaker 1: them until you get the face that you want out
Speaker 1: of that. So instead of me asking you to take
Speaker 1: out a piece of notebook paper and draw seth Rogen,
Speaker 1: instead I say, look, here's a bunch of eyes and
Speaker 1: noses and mouths, and I want you to flip these
Speaker 1: around until you get a good picture of seth Rogen
Speaker 1: or the person that you saw or the perpetrator. So
Speaker 1: the first system for this was introduced in the late
Speaker 1: nineteen fifties by the Los Angeles Police Department. It was
Speaker 1: these features on transparent sheets and you rotate them around
Speaker 1: and you reconstruct the face. This was called Identicit, and
Speaker 1: Identicate was used by Scotland Yard in a case in
Speaker 1: nineteen sixty one, a woman was stabbed to death in
Speaker 1: an antique shop where she work, and the police interviewed
Speaker 1: people and learned that someone suspicious had been in the
Speaker 1: shop a few days earlier, and so Scotland Yard turned
Speaker 1: to this invention from America and had their witnesses compile
Speaker 1: the suspect's face using identicit, And some days later a
Speaker 1: policeman saw a man named Edwin Bush on the street
Speaker 1: and recognized him from the identicate pictures in the newspaper,
Speaker 1: and in fact, when they arrested him and took him
Speaker 1: to the station, they found he had a copy of
Speaker 1: the newspaper drawing in his own pocket, and his shoes
Speaker 1: matched the size of the shoes in the crime scene,
Speaker 1: and so on, and he ended up confessing to the murder.
Speaker 1: So this was considered a real success in how you
Speaker 1: could crank up the reliability of identifying people and identic
Speaker 1: It was eventually replaced by photo fit in the nineteen seventies,
Speaker 1: where instead of using drawings, you use collages of photos
Speaker 1: of eyes and ears and noses and mouth and hairline
Speaker 1: and so on, and the photos give a better image
Speaker 1: of the suspect's face rather than the line drawings. And
Speaker 1: with due course all this evolved into software in which
Speaker 1: you take a three dimensional model of the head and
Speaker 1: you do the same sort of thing where you can
Speaker 1: change the eyes and nose and mouth and eyebrows and
Speaker 1: so on. And there were many stories that came out
Speaker 1: of all these systems and that increased confidence in the approach.
Speaker 1: But it turns out that despite success stories with this,
Speaker 1: when you really start looking into it, it turns out
Speaker 1: these face recognition approaches are generally not so good in
Speaker 1: terms of being able to identify people. Some years ago,
Speaker 1: an MIT researcher named Pawan Sinha got a hold of
Speaker 1: the standard facial software that police forces use, and he
Speaker 1: requested an expert with several years of experience with the
Speaker 1: system to put together reconstructions directly from a picture and
Speaker 1: without time constraints. That meant the operator didn't have to
Speaker 1: rely on verbal descriptions. He could just look at the
Speaker 1: photos and put this together. So each year in my class,
Speaker 1: I show the students these four photographs and I offer
Speaker 1: ten dollars to whoever can identify the pictures, and no
Speaker 1: one ever can. There are lots of wrong guesses, but
Speaker 1: so far no one has gotten them. Right. Now, the
Speaker 1: pictures are of Bill Cosby, Carl Sagan, Ronald Reagan, Michael Jordan.
Speaker 1: Now I get it. These are faces that the younger
Speaker 1: generation can't necessarily identify anyway. But at the peak of
Speaker 1: these guys popularity in the nineteen eighties, people couldn't identify
Speaker 1: these pictures. Then the reconstructions just weren't close enough to
Speaker 1: the actual face to make the match. And in case
Speaker 1: you think this might just be a laboratory artifact, there
Speaker 1: are plenty of real life cases where you look at
Speaker 1: the identicate composite and then you look at the captured
Speaker 1: person's photograph and you'll know right away that you would
Speaker 1: have never identified that person from that drawing. Why. Well,
Speaker 1: part of the problem is that the feature based composite
Speaker 1: image is built from the pieces and parts. You say,
Speaker 1: I think the guy's eyes looked sort of like this,
Speaker 1: and his mouth looked sort of like that, and his
Speaker 1: nose and his eyebrows and so on. But that's not
Speaker 1: the way the human visual system works. It recognizes faces
Speaker 1: based on the whole picture. What's called the gestalt, which
Speaker 1: is the German word that signifies when a whole is
Speaker 1: perceived as more than the sum of its parts. But
Speaker 1: that is only one problem. Let's imagine that you could
Speaker 1: somehow reconstruct a pretty good likeness there's also the problem
Speaker 1: of similarity, which is to say, a lot of people
Speaker 1: just look alike. So there was an amazing case some
Speaker 1: years ago in which a man named Lawrence Berson, who
Speaker 1: had curly hair and big square glasses, was convicted of
Speaker 1: several rape cases and went to jail. And then another guy,
Speaker 1: George Morales, with curly hair and big square glasses, was
Speaker 1: convicted of several robberies and went to jail, and both
Speaker 1: protested their innocence, and it turns out they were telling
Speaker 1: the truth. The guy who did all of the crimes
Speaker 1: was a guy named Richard Carbone, who had curly hair
Speaker 1: and big square glasses. Carbone had been described by several eyewitnesses,
Speaker 1: and these two other poor guys served jail time because
Speaker 1: they were picked out of the police lineups. And putting
Speaker 1: a photo of these guys on eagleman dot com slash
Speaker 1: podcast because it's so striking how different people can look
Speaker 1: similar to one another. So I've told you so far
Speaker 1: that the brain in codes faces holistically, not in bits
Speaker 1: and parts, and also that a lot of people look
Speaker 1: roughly similar. But neither of those problems even competes with
Speaker 1: the biggest problem of eyewitness testimony, and that is our
Speaker 1: memories are terrible. We all like to think that we
Speaker 1: can remember a face in describe it, but as my
Speaker 1: students saw from trying to draw the woman who broke
Speaker 1: into my classroom and spoke angrily with me for a minute,
Speaker 1: it's really hard to remember the details of someone's face
Speaker 1: and then try to reconstruct that. And the past few
Speaker 1: decades have seen really great studies which undermine our confidence
Speaker 1: that this should be easy to do. So the first
Speaker 1: thing to appreciate is that there are two phases of memory.
Speaker 1: The first is encoding, So when the woman burst into
Speaker 1: my classroom, the students were encoding what they were seeing.
Speaker 1: Their brains were writing it down, and the second phase
Speaker 1: is retrieval, or pulling the memory back up later. In
Speaker 1: the case of my classroom, I waited about thirty minutes
Speaker 1: before asking them to draw the face, and it turns
Speaker 1: out the forgetting curve is quite steep. By thirty minutes in,
Speaker 1: they've forgotten most of the important details. So let's break
Speaker 1: these down one at a time. We'll start with encoding,
Speaker 1: writing down the memory. One of the biggest problems with
Speaker 1: encoding a memory during a crime is what's called weapon focus.
Speaker 1: So if a person has a knife on you, or
Speaker 1: is wielding a gun, or has a baseball bat or whatever,
Speaker 1: your brain can't help but to be focused on that,
Speaker 1: and as a result, it's harder to remember details about
Speaker 1: the person's face. So here's another study from Elizabeth loftis
Speaker 1: she has you come into a room and she tells
Speaker 1: you you're going to participate in some psychology exam. And
Speaker 1: while you're waiting there, you hear two people arguing, and
Speaker 1: then one person comes out of the room and he's
Speaker 1: got some grease on his hands and he's holding a pen.
Speaker 1: So that scenario one. Scenario two is to hear the
Speaker 1: same thing, the two people arguing, and then the guy
Speaker 1: comes out and he's holding a blood stained knife. And
Speaker 1: then she studies how well you can identify the person
Speaker 1: after that, And you can imagine what happens when the
Speaker 1: guy is holding the blood stained knife. How good is
Speaker 1: your identification about what his face looked like. It's terrible.
Speaker 1: When there's a weapon involved, witnesses are not encoding the
Speaker 1: details about the person. They have high anxiety and they're
Speaker 1: staring at the weapon. It's the most salient thing in
Speaker 1: the scene. It is the ball to keep your eye on,
Speaker 1: so weapon focus is one problem. A second problem with
Speaker 1: encoding memory during a crime scene is what is called
Speaker 1: Q overload. When there's a really salient scene going on,
Speaker 1: when there's lots of stuff happening, it's just hard to
Speaker 1: encode all of that. So let's say that the woman
Speaker 1: had come into my classroom and she was not only
Speaker 1: yelling at me, but she starts throwing something at me.
Speaker 1: And then as soon as that happens, I pull out
Speaker 1: a taser and then a student over on the left
Speaker 1: starts screaming, and suddenly a student on the right leaps
Speaker 1: up and says, I'm going to protect doctor Eagleman and
Speaker 1: dives in to tackle her. Imagine, all this stuff is happening,
Speaker 1: bang bang bang, Well, it's really hard to encode all
Speaker 1: that because there's just too much going on at the
Speaker 1: same time, too many salient events happening at once. That's
Speaker 1: the Q overload effect. A third problem with encoding memory
Speaker 1: has to do with what's called the other race effect.
Speaker 1: We're much better at encoding faces of people who look
Speaker 1: like us, but for people who look different, it's harder
Speaker 1: to catch the important details. Now, just to be clear,
Speaker 1: this isn't racism. It's not that you're discriminating against a group.
Speaker 1: The issue here is that the neurons in your visual
Speaker 1: cortex just aren't trained up on the details of those faces.
Speaker 1: It's a matter of what type of faces your brain
Speaker 1: knows well. In other words, depending on where you've grown up,
Speaker 1: you might have a difficult time making an accurate identification
Speaker 1: if you were shown a lineup of Cambodians or Icelanders,
Speaker 1: or mauor or Wigers or Inuits. It's not that you
Speaker 1: have anything against these cultures. It's that you've grown training
Speaker 1: your visual system on the faces particular to your culture,
Speaker 1: whatever that is, and now you're dealing with measurements that
Speaker 1: are all a little bit different, like the intraocular distance
Speaker 1: and the nose length and the frenulum and the chin
Speaker 1: shape and so on. And if that's not where your
Speaker 1: experience and expertise lies, you're going to be worse at it.
Speaker 1: So the other race effect often leaves eyewitness identification hobbled.
Speaker 1: And the fourth problem with encoding memories is that it
Speaker 1: often just performs worse when there's stress and trauma. During
Speaker 1: an event, something really awful and unexpected happens and it's
Speaker 1: simply not even part of what your world model thinks
Speaker 1: is a possibility, and so your brain has a difficult
Speaker 1: time encoding what the heck just happened. So these are
Speaker 1: all problems with encoding the memory in the first place,
Speaker 1: weapon focus, Q overload, other race effect, stress and trauma
Speaker 1: during the event. Now, encoding is only half the game,
Speaker 1: because retrieval is the other half. So let's say you've
Speaker 1: written down some sort of rough memory of the woman
Speaker 1: who came into the classroom. She's somewhere between five three
Speaker 1: and five nine. Okay, you encoded that sort of, but
Speaker 1: now there are problems with the retrieval of the memory,
Speaker 1: pulling up what was there in your brain. One problem
Speaker 1: is what's called the misinformation effect. If you're told something
Speaker 1: about a crime in terms of what happened at the scene,
Speaker 1: or who was there or what they looked like, that
Speaker 1: will become part of your memory and you may not
Speaker 1: be able to distinguish that from what actually happened. So
Speaker 1: Elizabeth Loftus and others have studied this by showing people
Speaker 1: a picture of a car to stop sign, and then afterwards,
Speaker 1: after after the picture is gone, they give a text
Speaker 1: description of the same picture, but in the text they
Speaker 1: say it was a yield sign. And then they have
Speaker 1: people draw the picture as they remember it, and they
Speaker 1: draw the original scene but with a yield sign. So
Speaker 1: they're told something after the memory was encoded. They're told
Speaker 1: that it was a yield sign, and when they're retrieving
Speaker 1: the memory, they believe that the whole time they saw
Speaker 1: the yield sign there instead of the stop sign. In
Speaker 1: the case of my classroom invader, you may remember that
Speaker 1: I told the students that I remembered the woman had
Speaker 1: sunglasses on top of her head. Well, she didn't have
Speaker 1: sunglasses on her head. I made up that fact and
Speaker 1: I asserted it, and a number of students incorporated that
Speaker 1: false item into their memory what they think they saw,
Speaker 1: and afterwards they felt certain that that was a part
Speaker 1: of their original memory. Now that might sound crazy, because
Speaker 1: you think I could distinguish my own memory from something
Speaker 1: someone else said, but it turns out you often can't.
Speaker 1: So misinformation after the fact is one problem that happens
Speaker 1: with retrieval. A second problem is what's known as unconscious transference.
Speaker 1: Now to explain this, I'm going to tell you an
Speaker 1: absolutely incredible true story. There's a British psychologist named Donald Thompson,
Speaker 1: and one evening he went on British television to talk
Speaker 1: about eyewitness testimony and memory. Unbeknownst to him, while he
Speaker 1: was on live television, a woman in England had her
Speaker 1: apartment broken into and she was raped. She went to
Speaker 1: the police and described Donald Thompson and had his face drawn.
Speaker 1: She insisted this was her rapist. He was arrested the
Speaker 1: next day, but he said, I have a watertight alibi,
Speaker 1: which is that I was in a live television studio
Speaker 1: sitting with the police commissioner. And it took a little
Speaker 1: bit of time for all this to get worked out
Speaker 1: and unraveled. But of course his alley was verifiable. What
Speaker 1: happened was he was on the television set she was
Speaker 1: getting raped, and she transferred her memory of the rapist's
Speaker 1: face to his face. She got confused about whose face
Speaker 1: was who. It's such a crazy irony that he is
Speaker 1: a memory expert, because it could have been anybody on
Speaker 1: the television, but there it is incredible but true. So
Speaker 1: unconscious transference is a problem where a victim can't distinguish
Speaker 1: between the perpetrator of a crime and some other face
Speaker 1: that they saw in the same context or a totally
Speaker 1: different context. So those are some of the problems with
Speaker 1: memory retrieval. And one of the places where these problems
Speaker 1: come up all the time is in the police lineup.
Speaker 1: So imagine that you are presented a lineup with several
Speaker 1: people and you have to make a choice about which
Speaker 1: person you saw doing the crime. Well, one of the
Speaker 1: things that started getting recognized in the nineteen sixties and
Speaker 1: went to the Supreme Court was the idea of police suggestibility.
Speaker 1: It turns out that if the police already have their
Speaker 1: man in mind, they already think it's Fred. Whether or
Speaker 1: not that's correct, they believe it's Fred, and they want
Speaker 1: you to say it's Fred. There are all kinds of
Speaker 1: ways that they can suggest that to you, including just
Speaker 1: things like positive feedback. So if you say I think
Speaker 1: that was the guy, they'll say, yeah, good job, that's
Speaker 1: what we think also, And it turns out that influences
Speaker 1: the confidence of the eyewitness. When the trial starts months later,
Speaker 1: you'll say I'm absolutely certain that it was Fred, even
Speaker 1: though you might not remember that you weren't certain at all,
Speaker 1: But because of the positive feedback, which can even be
Speaker 1: quite subtle, like you know, just a nod or a
Speaker 1: smile or whatever, your confidence goes way up. And thirty
Speaker 1: years of psychology studies in the laboratory have verified the
Speaker 1: power of this suggestibility. As a result, psychologists have made
Speaker 1: suggestions to police forces and this has spun all the
Speaker 1: way up to the Supreme Court, with the result that
Speaker 1: police are not allowed to have any suggestibility involved. One
Speaker 1: of the ways to take care of this is to
Speaker 1: make the lineup identification double blind. That means the police
Speaker 1: officer who is running the lineup doesn't even know who
Speaker 1: the main suspect is. And this way the person doing
Speaker 1: the identifying gets no feedback at all. And by the way,
Speaker 1: the main thing that everyone's worried about with lineups is
Speaker 1: false identification. If the perpetrator is in the lineup and
Speaker 1: you miss him, that's another kind of problem. But the
Speaker 1: really terrible problem is sending an innocent person to prison
Speaker 1: with the false belief that you have identified him. I'll
Speaker 1: give you another problem that psychologists and legal theorists have studied,
Speaker 1: and that's the issue of co witness contamination. The idea
Speaker 1: is that if you see a crime and I'm standing
Speaker 1: there and I see it too, and then we start
Speaker 1: talking about it with one another, we can't help but
Speaker 1: influence each other's memories. This is a close relative of
Speaker 1: the misinformation problem. If you remember that she had curly hair,
Speaker 1: but I say I'm pretty sure she had straight hair.
Speaker 1: Or if you think she was unathletic and I say, no,
Speaker 1: she was quite athletic, both our memories become contaminated by
Speaker 1: the other one statement, and we more and more come
Speaker 1: to believe things that we didn't originally. So one thing
Speaker 1: that police know to do straight away is to separate witnesses.
Speaker 1: And there are many many aspects that have come from
Speaker 1: research that are now built into the way that police
Speaker 1: optimally do lineups. For example, they try to make sure
Speaker 1: that you don't see photographs of a suspect before the lineup,
Speaker 1: because if you do, you're really likely to identify that guy.
Speaker 1: One place this comes up is contamination by photos in
Speaker 1: news stories. So CNN says the suspect looks like this,
Speaker 1: and then you're brought into a lineup, and whether or
Speaker 1: not you remember having seen that story on CNN, that
Speaker 1: influences your performance in the lineup. So many guidelines have
Speaker 1: come out of this research. I'll give you just a
Speaker 1: few examples. One guideline is to make sure that the
Speaker 1: eyewitness is aware that the perpetrator might not be in
Speaker 1: the lineup. Another is this double blind procedure that I
Speaker 1: mentioned that doesn't allow police to see the lineup, so
Speaker 1: they can't subject to the eyewitness to any of their
Speaker 1: suspicions as to who the suspect is, and courts are
Speaker 1: increasingly recognizing that this speed of recognition matters. Generally speaking,
Speaker 1: if the witness quickly identifies the perpetrator, then the selection
Speaker 1: is more likely to be correct. Finally, if the appearance
Speaker 1: of a person stands out amongst the otherwise undistinctive crowd,
Speaker 1: then an eyewitness is more likely to select that person,
Speaker 1: regardless of their own recollection of the criminal. This is
Speaker 1: known as the distractor or dud effect. So there are
Speaker 1: many places where scientific study has made d contributions to
Speaker 1: the optimal way to run. I witnessed identification procedures. Now
Speaker 1: what if somebody comes in and they say, I saw
Speaker 1: the guy, and I know with one hundred percent certainty
Speaker 1: that was the guy, Versus someone else who comes in
Speaker 1: and says, I don't know, I was looking out a window.
Speaker 1: It was a car robbery going on two stories below me.
Speaker 1: It was kind of dark. I couldn't really see him
Speaker 1: very well. I think that was the guy. I don't
Speaker 1: really know. Do you think those two scenarios should be
Speaker 1: treated differently? In other words, what is the relationship between
Speaker 1: confidence and accuracy? Well? The United States Supreme Court had
Speaker 1: to answer this question in nineteen seventy two in a
Speaker 1: case called Neil versus Biggers. What happened was that the victim,
Speaker 1: Margaret Beemer, was dragged into the woods and assaulted. She
Speaker 1: described her attacker to the police only in very general terms.
Speaker 1: Then she was shown a bunch of photographs and people
Speaker 1: who met the description, but she couldn't identify anyone from
Speaker 1: the photos or stand ups for seven months. So the
Speaker 1: police then get a guy on another charge, a got
Speaker 1: named Archie Biggers, and they decide to include him in
Speaker 1: a stand up, But they couldn't find anyone who made
Speaker 1: a good match to this guy's looks, so they did
Speaker 1: what's called a show up instead, where there's no one
Speaker 1: else there but the one suspect. So two detectives walk
Speaker 1: Biggers passed the victim, and at her request, the police
Speaker 1: directed him to say shut up or I will kill you.
Speaker 1: The testimony a trial wasn't clear as to whether she
Speaker 1: had first identified him and then asked that he repeat
Speaker 1: those words, or made her identification after he'd spoken. In
Speaker 1: any event, the victim testified that she had no doubt
Speaker 1: about her identification, and so Biggers was convicted, and he
Speaker 1: came back on appeal and argued it simply wasn't fair,
Speaker 1: this was unreliable. The lower courts agreed with him and said,
Speaker 1: no way, We're not accepting this as evidence because this
Speaker 1: identification process was extremely suggestive. But the US Supreme Court
Speaker 1: eventually heard this case and reversed that decision. They concluded
Speaker 1: it was okay why because she said that she was certain.
Speaker 1: In other words, they concluded that how confident a person
Speaker 1: is relates to how good their evidence is. They felt
Speaker 1: that high confidence allows you to judge the veracity of
Speaker 1: a witness. So, in other words, the Supreme Court said
Speaker 1: implicitly that they think there is a relationship between confidence
Speaker 1: and accuracy. But generally, cognitive psychologists find that this relationship
Speaker 1: is very weak. Because of all the things we've talked
Speaker 1: about in this episode. Confidence does not work as a
Speaker 1: yardstick of accuracy, especially as time goes on and I'm
Speaker 1: going to do an episode soon about how the legal
Speaker 1: system decides which technologies to allow into their courtrooms, But
Speaker 1: for now, I'm just going to point out that it
Speaker 1: requires passing high scientific standards. So how do you think
Speaker 1: eyewitness testimony compares well? A version of this question hit
Speaker 1: the US Supreme Court in twenty eleven Perry versus New Hampshire.
Speaker 1: I spoke with Sanjay Gupta on CNN about this case
Speaker 1: when it was getting decided. The question the court was
Speaker 1: asking was essentially, if there's lousy eyewitness testimony in a case,
Speaker 1: should it be allowed? When does that violate the right
Speaker 1: to do process? You'll write to a fair trial. So
Speaker 1: Perry was a young man in New Hampshire who got
Speaker 1: convicted of stealing a car, and he was convicted based
Speaker 1: in large part on a woman who was looking out
Speaker 1: a second story window in the dark. She couldn't see
Speaker 1: well from that distance. So Perry got convicted in a
Speaker 1: New Hampshire court, and they came back and tried to appeal,
Speaker 1: and he said, how can you possibly take this woman's
Speaker 1: word for it? How could you send me to jail
Speaker 1: based on such unreliable witness testimony? The lower courts upheld
Speaker 1: the decision, and so this question spun up to the
Speaker 1: US Supreme Court. The question that was on the table
Speaker 1: is does unreliable eyewitness testimony violate your constitutional rights? And
Speaker 1: what the court said is, look, the only thing we
Speaker 1: care about is whether there was suggestibility by the police.
Speaker 1: If the police manipulated the process, then the due process
Speaker 1: clause of the Constitution is applicable. But they said, this
Speaker 1: does not hold generally for eyewinness testimony. Using unreliable evidence
Speaker 1: against you is not unconstitutional. There's no right that you'll
Speaker 1: have great evidence. Instead, it's the job of the jury
Speaker 1: to figure it out, to weigh the evidence. So that's
Speaker 1: what the court decided. And reading between the lines, what
Speaker 1: do you think one of the concerns of the court
Speaker 1: was here, It's this, if you introduce a question about
Speaker 1: the reliability of the witness, then you would, in theory,
Speaker 1: require a pre trial hearing to determine if her testimony
Speaker 1: is acceptable or not. And what does that do to
Speaker 1: every single case running in the nation. One of these
Speaker 1: Supreme Court justices posed this during the case. He said,
Speaker 1: what about jailhouse testimony where someone in the jail says,
Speaker 1: my cellmate told me x Y and Z. Sometimes it's unreliable,
Speaker 1: sometimes it yields fruit. Do we require a pre trial
Speaker 1: hearing every time because it might not be reliable? So
Speaker 1: this is an issue that would overturn the way the
Speaker 1: whole court system works. And so, at least for the
Speaker 1: time being, the legal system knows that eyewitness testimony is terrible.
Speaker 1: It can be very unreliable, and yet with all the caveats,
Speaker 1: there's no choice but to let it remain. So in
Speaker 1: closing your memory is not necessarily what you think it is.
Speaker 1: Memory is not writing down what happened in zeros and
Speaker 1: ones and then reading that back out. There are many
Speaker 1: things that get in the way of good encoding and retrieval.
Speaker 1: I really recommend Jennifer Thompson and Ronald Cotton's book. For Jennifer,
Speaker 1: this was a complete pouring out of her guts on
Speaker 1: the table a cathartic enterprise where she had to allow
Speaker 1: that she put a man in jail for eleven years
Speaker 1: based on her certainty that that was the face she
Speaker 1: had looked into. She knew it was Ronald Cotton, and
Speaker 1: she wanted him to die. That's how she felt about
Speaker 1: this man. And then she found out that she was wrong.
Speaker 1: So the book is about what it's like from the
Speaker 1: inside to believe, you know, and all the steps that
Speaker 1: happened along the way that manipulated her memory. So to
Speaker 1: summarize what we talked about today, eyewitness testimony has a
Speaker 1: terrific sway on jurors, and yet it is variable in
Speaker 1: its accuracy. Now, just for clarity, it's not that eyewitness
Speaker 1: testimony always has to be wrong. Plenty of times someone
Speaker 1: IDs someone and it's correct. But memory is not like
Speaker 1: a video camera. It is a reconstruction, and many factors
Speaker 1: worse than the encoding and manipulate the retrieval. As a result,
Speaker 1: we cannot say that confidence and accuracy are tightly linked,
Speaker 1: especially as time goes on. Eyewitness testimony is not going
Speaker 1: away from the courtroom because often it's the only evidence
Speaker 1: that we can bring to bear in a case. So,
Speaker 1: even though it may be the worst technology that we
Speaker 1: allow in the courtrooms, it is presumably here to stay.
Speaker 1: But remember, like much about our perception of the world
Speaker 1: that I'll be discussing throughout these episodes, just because you
Speaker 1: believe something to be true doesn't necessitate that it is.
Speaker 1: Go to Eagleman dot Com, Slash podcast for more information
Speaker 1: and to find further readings and to see some photographs.
Speaker 1: Send me in email at podcasts at eagleman dot com
Speaker 1: with questions or discussion, and I'll be making an episode
Speaker 1: soon in which I address those. Until next time, I'm
Speaker 1: Dave Eagleman, and this is Inner Cosmos