Vsauce! Kevin here -- Jennifer Thompson studied every detail of her attacker's face
as she was being sexually assaulted at knifepoint. His hairline, broad cheekbones,
a mustache that looked like a pencil-thin dirt smear. She couldn't fight back physically,
but MENTALLY she could memorize every little detail and bring him to justice.
Police described Jennifer as the best witness they'd ever
had. Her eyewitness testimony convicted Ronald Cotton, and he was sentenced to
life in prison plus 50 years despite no physical evidence linking him to the crime.
There was no evidence because he didn't do it -- and 11 years later, DNA testing proved it.
So how could the "best witness ever" get it completely wrong? Why do about
70% of DNA exonerations in the US involve eyewitness misidentification?
And how can what we've seen turn into something we never saw?
[intro]
I need you to… point to the shape that rolled over your foot on the evening of March 14th,
2015. Okay, this example seems stupid, but it shows one of the many, many problems with witness
identification. Only one shape in the lineup comes close to the description of the suspect,
the choice is obvious. Only a circle can roll! Now this lineup requires an
actual identification of size and color.
But here’s a question. How do you even get to a lineup? First, you need a description.
Jennifer Thompson studied pages of ears, chins, and noses so police could reconstruct her
attacker's face using an IdentiKit. In 1984, that was a sketch on paper -- now
the IdentiKit is digital. The hand-drawn facial composite looked nearly perfect to her. Now the
police had a picture of the suspect that could be broadcast on the local news.
Here’s the problem.
Some witnesses are amazing -- their autobiographical memory of an event is flawless.
But then there’s the rest of us, and Hugo Münsterberg wrote the book on how what we forget
and what we don’t know becomes an illusion that replaces reality.
In 1908, Münsterberg published “On the Witness Stand,” a collection of articles and essays about
psychological factors that affect trial outcomes. What’s more persuasive than a witness pointing to
a defendant and swearing they did it? Münsterberg insisted THAT gold standard of evidence in a trial
was actually… really untrustworthy. Trials pre-date the ancient Greeks,
and while we’ve always known witnesses could lie, only recently do we understand how easy it is to
THINK you’re telling the truth when your brain is just… wrong.
Münsterberg suggested that justice often miscarried due to the “treachery of human
memory” -- and to prove it, he pointed the finger at himself. He wasn’t just some academic
pontificating on criminal justice theory -- he was robbed, and as a witness, he messed it all up.
It went like this: He testified under oath that burglars entered his house through a window. They
actually came in through the cellar. He said they left a clock packed in paper. It was wrapped in a
tablecloth. He gave a complete list of garments that were stolen; it turns out they took 7 more
than he said. He claimed he found candle wax on the 2nd floor… but the wax drippings were actually
in the attic. Finally, he reported 2 burglars. But maybe it was just 1 -- he had no way to tell.
Münsterberg had given over 3,000 academic lectures and not once had to use note cards. His mind and
memory were amazing. But he admitted that he’d rushed into the house and surveyed it all quickly,
noting after the fact that his brain filled in the gaps for him. The burglar was eventually
caught breaking into another house, and they found Münsterberg’s jacket in his apartment.
But the fact is -- the world’s expert on witness reliability -- was almost completely wrong.
He said, “I felt myself somewhat alarmed in seeing how many illusions had come in.”
So…
If the pioneer of witness reliability scholarship couldn't overcome
his illusions, what chance did a college student traumatized by a violent sexual assault have?
Police presented Jennifer Thompson with a photo lineup of 6 men. They told her that the suspect
might not even be in the lineup -- but she figured if he wasn’t there, why would they
bother? She recognized one of the photos and chose Ronald Cotton with absolute certainty.
A week later, Jennifer recognized the same man in a physical lineup. To her, the parts that didn’t
match her memory made him even guiltier -- like he’d changed his hair to purposely deceive her.
The photo lineup reinforced her mental image of her attacker, and anti-proof became proof.
Police confirmed that she’d chosen the same man in both lineups. She said,
"It was him. There was no doubt in my mind."
Did you feel absolutely certain? Absolutely certain. Well, what was said to me afterwards was,
“That’s the same person you picked out in the photo lineup.” So in my mind I thought,
“Bingo! I did it right!”
So if that’s the case… How can the truth compete with that?
“Estimator variables” are the parts of eyewitness identification that police can’t control. So like,
cross-racial ID’s tend to be less accurate than ID’s within a witness’s race. That isn’t
the police’s fault. People think different things, and they just plain see different
things -- from an optical illusion to the colors of a dress. But the real enemy of memory is time.
Hermann Ebbinghaus’s forgetting curve provides a visual representation
of how quickly your memory can erode -- and as early as the 1880’s
his equation expressed the vulnerability of memory over time. But forgetting over time
is only half the problem -- the other half is teaching yourself the lie.
Every time you re-tell your story to police, to a lawyer, to a journalist, to a friend,
you’re essentially engaging in the spaced repetition of practice.
You’re learning. Your memories get clearer, almost like memorizing lines for a play.
So the longer it’s been, the more you forget. The more you forget,
the more you invent. The more you repeat, the more confident you are -- whether it’s true or not.
Jennifer Thompson said, “If there was a death penalty,
I wanted Ronald Cotton to get it. I would pull the switch if they let me.” When she pointed
her finger at Cotton to identify him during the trial, she said she wished it had been a gun.
Ronald Cotton had become her attacker in her mind through unconscious transference.
But there was no physical evidence -- no fingerprints, no clothing, no fibers from
the victim’s apartment -- linking Ronald Cotton to the crime. He maintained his innocence and
refused to entertain a plea bargain. He was convicted based largely on Jennifer’s testimony.
3 years later, Jennifer Thompson came face to face with her actual attacker -- and
didn’t even notice.
Ronald Cotton was given a new trial -- that’s great, right? WRONG -- this time he also faced
charges for another assault and burglary from that same night. Meanwhile, he’d met a man in
prison who looked a lot like Jennifer’s original composite sketch -- and he looked so similar to
Ronald Cotton that other inmates couldn’t tell them apart. Bobby Poole lived in the same town as
Ronald and Jennifer, and he was currently serving a sentence for sexual assault. If all of that
wasn’t enough to raise suspicions, he’d literally confessed to other inmates that he assaulted her.
Ronald’s lawyers called Bobby Poole as a witness in the new trial. Poole
denied everything. Jennifer Thompson had wanted to be the one to personally execute Ronald Cotton,
but when she was in the same courtroom as her real attacker, the man whose face she’d studied,
she didn’t recognize him at all. Ronald was convicted again and sent back to prison.
Richard Rosen, a professor at UNC-Chapel Hill, and lawyer Tom Lambeth took on Ronald’s case.
They secured the DNA analysis that wasn’t available in 1984. Ronald insisted that
he'd be cleared -- and the stakes were high. A DNA match would cement his guilt.
Ronald wasn’t lying. The tests showed that not only was Ronald innocent, but that Bobby Poole
was the attacker -- and over 10 years after first being arrested, Ronald Cotton was free.
Jennifer didn’t dispute the DNA findings. She knew she’d been proven wrong. She wasn’t defensive
about it; she was horrified. She said, “I had to tell people not only was I was a rape victim,
but a rape victim with an extremely bad memory and someone had to pay 11 years for that.
I wondered how I could have been so stupid.”
Jennifer was not stupid. During the attack she actually convinced Poole to get rid of his knife,
then outwitted him by offering to get him a drink and using the distraction to escape.
She just fell prey to the vulnerabilities all witnesses have and
a few simple changes can drastically improve witness reliability.
Lineups that offer a range of similar choices are most effective -- that way suspects can’t
stand out. And making lineups sequential, so one photo at a time is compared to a witness’s memory
instead of being compared to one another, is even more effective.
Police need to make it clear to witnesses that the suspect might not be there -- and the cops
who make the lineup shouldn’t be the ones who administer it. That ‘double blind’ process
ensures police can’t give any verbal or non-verbal cues to the witness to influence their choice.
Recording the lineup solidifies the record,
and police should ask witnesses to detail their level of confidence in their choice.
But Jennifer Thompson would’ve said 100%, and advancing science
was the only thing that saved Ronald Cotton from a life in prison.
“In my mind, I was sure of what I saw. Um.
Thinking back on it, uh, I don’t know that I would’ve done anything different.”
Jennifer and Ronald are friends now. He never blamed her for being wrong.
They’ve given talks together nationwide,
their families are close, and they even end phone conversations by saying “Love you.”
Half the states in the US have instituted some form of eyewitness identification reform. But
can we make sure what happened to both Ronald Cotton and Jennifer Thompson never happens again?
Probably not. Hugo Münsterberg was right -- from biological limitations to systematic error,
the moment our eyes and ears capture something, the truth is vulnerable.
We can get better, but we'll never be perfect.
2,200 years ago, the Roman playwright Plautus said that “1 eyewitness is worth
10 ear witnesses.” People attest to the truth by saying they saw something with their own two
eyes. They’ll tell you that something is so good you need to see it to believe it.
But the truth is… sometimes you need to believe it to see it.
And as always, thanks for watching.