Vsauce, Kevin here.
Imagine the horror of being arrested in connection to a crime the entire world is reading about,
on the basis of irrefutable fingerprint evidence, that you KNOW you didn’t commit.
How do you defend yourself against a century of science and math that just… aren’t
wrong?
And how can you possibly win when you’re up against the FBI, and your own fingerprint
expert says your fingerprints are a match?
The first arrest of an American in connection with the Madrid train bombings… what led
the FBI to Portland, Oregon?
Supporters of the man say agents are on the wrong track.
In Spain, they call it 11M.
On March 11, 2004, just 3 days before Spain’s general elections, explosions ripped through
trains in Madrid.
193 people were killed and about 2,000 were injured.
Europe hadn’t experienced an attack on that scale in decades, and it came in the wake
of 9/11 and at the peak of the global war on terror.
Fingerprints were found on a bag that contained detonating devices, and Spanish authorities
put them into the Interpol database.
The FBI in the United States found a match to Latent Fingerprint 17, and in May, Brandon
Mayfield, a U.S. Army veteran and family law attorney who frequently worked with low-income
clients in Portland, Oregon, took the blame.
How does a lawyer 5,403 miles away from a crime become its prime suspect?
To understand what went wrong here, we need to go all the way back to Darwin.
Throughout the 1800’s, scientists advanced the notion that a pattern of epidermal ridges
on human fingertips, toes, and palms were unique to each human, and they could be used
as a proof of one’s identity -- like a built-in biological signature.
Scottish surgeon Henry Faulds proposed that they could be cataloged and recorded with
ink, and he asked Charles Darwin for help.
Darwin was a bit too old to undertake a real analysis, so he passed it onto his cousin
Francis Galton -- whose many accomplishments included identifying the statistical regression
to the mean and inventing a physical board to demonstrate it that we now see on game
shows.
The science around fingerprint identification flourished, and by the beginning of the 20th
century, it had become one of the best ways to pinpoint criminals -- and especially repeat
offenders.
It replaced systems like branding skin, which France outlawed in 1832.
It was much more scientific than Alphonse Bertillon’s anthropometric forensics, a
measurement of physical factors including head length, head breadth, length of middle
finger, length of the left foot, eye color and hair color -- by assigning values for
each, Bertillon claimed each person would have a unique combination of data.
Except… it wasn’t all that unique, since so many physical attributes correlate with
one another.
Like, most tall people also have long arms, you don’t find many 5 foot 3 men with 7-foot
wingspans.
Fingerprints were much more accurate, and Bertllon developed a system of 16 identifiable
markers that remained standard for over a century.
Starting in 1924, the US government began compiling and cataloging fingerprints, and
by 2004, they had about 200 million on file.
A wavelet scalar quantization algorithm was employed to compress the 500 pixel-per-inch
images down to a file size of just 500kb -- which meant easier storage, quicker access, and
smoother online transfers globally.
Like to Spain.
And by that time, it had been a century since Francis Galton’s forgotten warning that,
“A complex pattern [like fingerprints] is capable of suggesting various readings, as
the figuring on a wallpaper may suggest a variety of forms and faces to those who have
such fancies.”
Even though the prints sent from Spain were low quality, an FBI examiner signed an affidavit
stating that, “the FBI lab stands by their conclusion of a 100 percent positive identification.”
In the weeks leading up to his arrest, Brandon felt like he was being watched… because
he was literally being watched.
FBI documents show that as soon as Brandon’s fingerprints popped as a potential match,
he was immediately under 24-hour FBI surveillance, including phone and digital monitoring.
He also suspected break-ins at his home and his office, because… they were both really
broken into.
They were convinced Mayfied was involved.
Here’s a question!
If fingerprints are so foolproof, why was an innocent man harassed by the government
and detained for weeks as he wondered why they thought he was connected to a crime on
another continent?
We’ll explore that in a second.
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Okay so.
Spanish authorities actually knew Mayfield’s print wasn’t a match -- before the FBI detained
him.
They communicated a result of “Negativo” after their own fingerprint experts found
too few points matching in the prints.
So what’d the FBI do?
The FBI flew to Madrid and told them they were wrong.
As they investigated Mayfield, they found that he’d converted to Islam.
They also noted that a year prior to 11M, he’d represented a man accused of involvement
in a terror plot in Oregon.
The more they looked into his life, the more circumstantial evidence they found that suggested
Mayfield had the means and motive to play a role in the attack -- and that’s actually
the punchline to a joke about a lying Texas sharpshooter.
The joke’s about a man who shoots at the side of a barn, and then draws a target around
a cluster of bullet holes to suggest that he’s actually a great shooter.
When that’s done with data, it’s called the “multiple comparisons problem.”
When we falsely perceive connections in our heads, it’s “apophenia.”
And when you’re fitting evidence to a predetermined conclusion, that has a name too.
Psychologist Peter Wason coined the term “confirmation bias” to describe one’s tendency to focus
on evidence that supports their beliefs and to ignore or reject evidence that contradicts
it.
Basically, it’s cherry-picking the truth, and it almost guarantees that you’ll find
exactly what you’re looking for -- even if that isn’t reality.
SO WHAT WAS THE REALITY?
An FBI report years after the incident admitted that Mayfield was actually one of 20 potential
matches to the LF-17 fingerprint.
Once they looked into Mayfield’s life and found details that supported their suspicions,
he became the prime suspect.
Because he served in the military, he probably had the knowledge to be involved.
His tangential past connections to suspected terrorists were further proof.
And since he’d converted to Islam, he checked almost every box on the FBI’s profile list.
And remember Mayfield’s house being searched?
Evidence was seized from his residence, including what the FBI called “Spanish documents.”
They turned out to be his son’s Spanish homework.
Okay, okay, okay.
But why did Mayfield’s own defense experts agree with the FBI that his prints were a
match?
They both claimed there was an “unusual similarity” between the two prints, with
the Office of the Inspector General noting that they considered the coincidence to be
“extraordinarily rare.”
And now we’re back to people being accused of crimes based on hypothetical low probability
-- just like Sally Clark’s tragic case in my last video.
The FBI deliberately manipulated their conclusions by ignoring that the LF-17 print was only
a slight match with Mayfield’s -- and then they focused on evidence that supported Mayfield’s
guilt and ignored the parts that didn’t.
But the FBI’s bad judgment was also a function of a weird problem we have when we get better
at collecting and using data.
Think of crime in Galton’s era -- there was essentially no real information to work
from.
It was very difficult to verify a suspect’s identity.
It was hard to find a suspect given that there was no video evidence, hardly any photography,
and primitive forensics at best.
It would be generations before we could begin to collect and process things like blood types
and DNA.
The FBI didn’t have too little data.
They actually had too much.
They knew every little detail about Brandon Mayfield’s life, from his browser history
to what was in his garbage.
The sheer volume of information made it easy for them to find exactly what they were looking
for and only what they were looking for.
Here’s an example of how that data and knowledge gap quickly goes wrong.
Swedish power lines.
In 1992, Swedish researchers concluded a 25-year longitudinal study to determine whether living
near high-voltage power lines made people sick.
They studied the rates of over 800 different illnesses and found that childhood leukemia
was 4 times more common near power lines.
Their data wasn’t wrong.
The problem was... by measuring so many variables, they basically guaranteed that at least ONE
of them would be a weird statistical outlier -- and then they used it as proof of a cause-and-effect
relationship.
You can actually visualize what this is like.
Look.
If I have a bag of dice and dump them all on my table, what’s gonna happen?
Most of them will form a scattered pile right under where I dump them.
But you KNOW that 1 or 2 of em are gonna fly off my table, bounce on the carpet, and lodge
themselves under a filing cabinet 10 feet away.
Why?!?
They’re outliers, it just happens.
Alright, back to Mayfield.
The FBI had a preconceived notion of who was likely to have been involved in 11M.
They had seemingly-reliable forensic evidence to support a suspect’s identification.
They had so much information about that suspect, all so easily available digitally, that they
could find information that perfectly fit their profile.
They dismissed the high volume of exculpatory data… like whether Brandon Mayfield was
even in Europe before M-11.
HE WASN’T. His passport had expired years ago -- but the FBI claimed that meant Mayfield
must’ve traveled under another identity.
For them, the absence of proof was proof.
Mayfield was detained for 2 weeks as a “material witness” -- NOT arrested as an actual suspect,
since holding him as a material witness required far less evidence.
The FBI kept collecting information they thought proved Mayfield’s guilt -- but everything
came crashing down when Spanish authorities announced that they’d found the person who
was actually involved in 11M.
They matched the LF-17 print to those of an Algerian terrorist, and they were right.
The FBI’s experts agreed that these prints were truly a match.
Mayfield was released immediately -- and then the questions began.
As the American Civil Liberties Union and other civil rights advocates excoriated the
FBI for having wrongly profiled him, the FBI analyzed what went wrong internally.
They laid part of the blame on what they saw as the poor quality of the original digital
image of LF-17, but a panel of international fingerprint experts suggested that the FBI
had far too much confidence in the Integrated Automated Fingerprint Identification System,
which is the largest biometric database in the world, and let the pressure of a high
profile case determine how they viewed the evidence -- and what evidence they collected
at all.
The panel also concluded that, “FBI culture discouraged fingerprint examiners from disagreeing
with their superiors.”
The Department of Justice released a 330-page report that admitted to analytical and procedural
errors, and academic journals churned out articles analyzing the validity of fingerprint
analysis, the rate of false positives, and fingerprinting’s role in criminal trials.
Regarding the validity of fingerprinting, a science historian at UC-Irvine said, “How
do you explain to the court that what you’ve been saying for 100 years was exaggerated,
but you still have something meaningful to say?”
Mayfield’s case led to lawsuits about potential misuse and constitutionality of the Patriot
Act, a $2 million judgment in his favor, and a formal apology from the US Government.
Mayfield went back to practicing law.
Nearly two decades after Mayfield’s unconscionable injustice, we have even more data and information
about everything -- and about everyone.
It’s amazing how much we can know and how quickly we can know it.
Everything from medical records to finding a gem mint Charizard is way faster than it
used to be, and usually more accurate.
That’s generally a good thing.
But… sometimes all that information is a problem.
Even when it’s perfectly accurate, the way we use it might not be.
We can make good data bad, and it’s getting even more difficult to get it right.
Mayfield’s case highlights the complex relationship between the objectivity of science and math
and the fallibility of the human mind.
As we advance, we find more ways to be right -- and that also means more ways to be wrong.
The not-quite-100% reliability of fingerprint analysis may have initially failed Brandon
Mayfield, but the unchecked flaws of the human mind are what landed him in a jail cell.
Sometimes the math and science are right, and the way we use them, the way people use
what’s right... is wrong.
And as always, thanks for watching.