0:05

Can you measure pedophilia in

0:07

a brain scan? Can you measure

0:09

a lie from somebody's blood pressure?

0:12

And how should a judge in court

0:14

who's not an expert in science decide

0:17

these things? What does any of this have

0:19

to do with President Ronald Reagan or

0:22

antisocial personality disorder

0:24

or how the television show CSI

0:27

has impacted courtrooms. Welcome

0:32

to Inner Cosmos with me David Eagleman.

0:35

I'm a neuroscientist and an author at

0:37

Stanford and I've spent my career at

0:39

the intersection of our brains

0:41

and our lives. In today's episode

0:44

is about an aspect of

0:47

the intersection between brains and

0:49

the legal system, and it's a tricky

0:51

one. The

0:57

question is when neuroscience

1:00

techniques are allowed

1:03

in courts, When should they be allowed?

1:05

What bars need to be passed

1:08

for a technology to be accepted.

1:11

So let's start on March thirtieth,

1:14

nineteen eighty one, when the President

1:16

of the United States, Ronald Reagan, has

1:18

been delivering a speech and

1:21

afterwards, he and his team are returning

1:23

to his limousine and he gives

1:25

a two big arm wave to the

1:28

crowd and suddenly there

1:30

are gunshots ringing out and

1:33

everyone's diving, and President

1:35

Reagan is hit with a ricochet off

1:37

his limousine, and Press Secretary

1:39

James Brady falls and

1:41

Secret Service agent Tim McCarthy falls,

1:44

and a DC Police officer named Thomas

1:47

del Haunty is also wounded, and

1:49

the President arrives at the

1:51

emergency room in critical condition

1:54

and almost dies. And for

1:56

those of you who weren't alive in nineteen eighty

1:58

one, or for whom this has re seated

2:00

in memory, just try to picture

2:03

the horror that this entailed. Now

2:06

you may remember that the gunman, John

2:08

Hinckley, had a deep psychosis.

2:11

He was divorced from reality,

2:13

and he believed that if he shot

2:16

the president, he would win the

2:18

love of the actress Jody Foster.

2:21

There's a lot to say about this case, and

2:23

in episodes thirty six and thirty seven

2:26

I talked about the insanity

2:28

defense, but here I want to zoom

2:30

in on a very particular aspect.

2:32

The thing most salient to us

2:35

today was the fact that this was

2:37

the first high profile case to use

2:39

a form of brain imaging.

2:42

Hinckley's lawyers pled not

2:45

guilty by reason of insanity, and

2:48

to support their defense, they introduced

2:50

brain imaging evidence so

2:53

his defense counsel argued that

2:56

he was schizophrenic, and they

2:58

argued they could prove this by

3:00

showing CAT scans or

3:02

CT scans. CT stands

3:05

for computer aided tomography

3:07

or computerized demography. Now,

3:09

the lawyers on both sides agreed

3:12

that cat scans had never before

3:14

been admitted as evidence

3:16

in a courtroom. Neuroimaging

3:19

was brand new at this time, So

3:22

should the judge allow this new

3:24

Fengal technology to be

3:26

accepted or not? Well,

3:29

it's not obvious. Can you really

3:31

tell if someone suffers from schizophrenia

3:33

just by looking at an anatomical

3:36

picture of the brain. It's

3:39

not obvious. So the judge decided

3:41

to dismiss the jury so that he

3:43

could hear the arguments about

3:45

whether or not the technology was

3:48

relevant and should be admitted. And

3:51

expert witness, a physician, pointed out

3:53

that Hinckley's soul

3:55

sigh, which are the valleys running along

3:58

the outside of the brain, these were

4:00

wider than average, and this

4:02

physician cited a paper suggesting

4:05

a connection between schizophrenia

4:08

and wider sulsie.

4:10

So the assertion was, if you have

4:12

schizophrenia, you can see

4:14

that just by looking at a cat scan

4:17

of the brain. So this doctor

4:19

said, quote the fact that

4:21

one third of schizophrenic participants

4:24

in the study had these widened

4:26

sulsie whereas in normals probably

4:28

less than one out of fifty have them. That

4:31

is a very powerful fact. But

4:33

the prosecution rebutted

4:36

this. They said, no way, it has not been

4:38

proven that a cat scan

4:40

can aid in the diagnosis

4:42

of schizophrenia, and therefore this

4:45

evidence should not be presented

4:47

to the jury. In other words, they

4:49

argued the technology should be excluded

4:52

from the courtroom because it was not yet ready

4:54

for prime time. The judge

4:57

listened to the arguments and

4:59

he finally decided that he would not

5:01

admit the cat scan. Then

5:04

nine days later he heard more expert testimony

5:07

and he confirmed that he would not take the

5:09

cat scan. And then he

5:11

changed his mind and reported he would

5:13

take the cat scan. Okay, So what

5:16

is this back and forth illustrate? It illustrates

5:19

the difficulty for a judge to

5:21

decide what makes meaningful

5:24

evidence and what does not. In

5:26

the end, Hinckley was found

5:29

not guilty by reason of insanity, although

5:31

that had little or nothing to do with the cat

5:33

scan. But this high profile case

5:36

is just one of hundreds

5:38

where this question comes up, should

5:40

neuroimaging be allowed in

5:42

the courtroom. There's no single

5:45

answer to this question, and in part that's

5:47

because there are many different guyses in

5:49

which it comes up. And so that's what we're

5:51

going to talk about today. We're going to talk

5:53

about how any technology gets

5:56

into courtrooms. So

5:58

to motivate this, imagine

6:01

that we start seeing advertisements

6:03

for a new Silicon Valley

6:05

company that has developed a new mind

6:08

reading technology. They call

6:10

this the Palo Alto three

6:12

thousand, and they strap it to your head

6:15

and they measure some brain waves and

6:17

pass that through a large language

6:19

model, and they print out in words

6:22

to a screen what you are thinking.

6:24

So you might be thinking about wanting

6:26

a hot dog with pickles. In this machine

6:29

will print to the screen, I want

6:31

a hot dog with pickles. Now

6:33

this is totally made up, but pretend it's

6:35

true. In a few years that said

6:38

company launches, and

6:40

let's say the technology looks pretty good.

6:42

It captures the gist of what

6:45

you are thinking about. Now, the question

6:47

is should this be admissible

6:50

in a court of law. Let's

6:53

imagine that someone puts it on

6:55

and states under oath that on April

6:58

twenty fifth, he was getting dinner with his family,

7:00

but suddenly the screen prints out I

7:03

committed the crime. Now, how do you

7:05

know whether to believe that or not? The

7:08

company is started by a

7:10

handful of young people who dropped out of college,

7:13

and they claim to be experts in neuroscience,

7:15

But how do you know whether it really

7:19

works? And especially in a high

7:21

stakes situation, should you accept

7:23

this in a court of law or

7:25

not? Well, some people, in order

7:27

to judge the quality of the technology, they

7:29

ask, well, are they charging for this technology?

7:32

But that's not a meaningful measure.

7:34

Of course they're charging. They can't develop

7:37

new technologies for free, anymore

7:39

than you would expect Apple to not

7:41

charge for their laptop. But the fact

7:44

that they're charging certainly doesn't rule

7:46

in or out anything about its efficacy.

7:49

So how do you know whether the technology

7:52

is efficacious? Can it be used in a

7:54

court of law? How do you know whether

7:57

it works and provides what the legal

7:59

system calls probative value,

8:02

which means can it do what it's supposed

8:04

to do? Can it provide sufficiently

8:06

useful evidence to prove

8:09

something in a trial? So

8:11

this is what we're going to talk about today.

8:14

Most of the time we don't realize that

8:16

new technologies always have to be assessed

8:19

by courtrooms to know whether

8:22

they should be accepted or rejected.

8:24

And some get in and then we take that as background

8:27

furniture, and others never make it. And

8:30

what we're going to see today is how and

8:32

why. So fast forward

8:34

some decades from the Hinckley trial.

8:36

Where are we now? What is

8:38

allowed in the courtroom? Well, we have

8:41

more sophisticated technologies

8:43

to image the brain. Now, for example,

8:46

we can get a picture of the

8:48

brain in an MRII

8:50

scan. Magnetic resonance imaging MRI

8:53

gives you a snapshot

8:55

of what the brain of a person looks like.

8:58

You're not seeing activity there,

9:00

You're just seeing the anatomy. Think

9:02

of this an analogy to the way you would

9:04

look at someone's skeleton with an X ray.

9:06

You can't see anything moving around what

9:08

you see as a snapshot. So

9:11

with MRI you can hope to see

9:13

abnormalities like a tumor

9:16

or evidence of a stroke, or the

9:18

consequences of a traumatic brain

9:20

injury. Now, I've been

9:22

called by many defense lawyers over

9:24

the years who say, I have a client

9:26

who's going up for trial. Can you take

9:28

a brain scan and see if you

9:30

can find something wrong with their brain,

9:33

so this can serve as a mitigating

9:35

factor. But I always tell them the same

9:37

thing. If you find something wrong with your

9:39

client's brain, that can serve

9:41

as a double edged sword. The duray

9:44

might think, Okay, I'm convinced there's something different

9:46

about this man's brain. But this

9:48

presumably means he'll be predisposed

9:51

to committing this kind of crime again,

9:54

so we should probably lock him up for a longer

9:56

time. So a defense lawyer has

9:58

to utilize this argument

10:00

with care. In any case, what

10:03

MRI gives you is an anatomical

10:05

snapshot. And now I want to tell

10:07

you about the next level of technology called

10:10

fMRI. Where the F stands

10:12

for fancy MRI. Okay, I'm kidding.

10:15

It stands for functional magnetic

10:17

resonance imaging fMRI. And

10:20

this is because it's telling you about the

10:22

function of the brain. It's

10:25

measuring blood flow to show

10:27

you where the activity in the brain just

10:30

was. This works because when brain

10:32

cells are active, they consume energy,

10:35

and the blood flow to that specific

10:37

region needs to increase so

10:39

that you can bring fresh oxygenated

10:41

blood to the area to restore

10:43

the used energy. So in fMRI,

10:46

we see where the new oxygenated

10:49

blood is going and we say, aha,

10:51

there must have just been some activity

10:53

there a few seconds ago. So

10:56

that's the difference between an anatomical

10:58

snapshot or a functional picture

11:00

of what's going on. Now. Part

11:03

of the reason that you can use the static

11:05

snapshot the MRI in court

11:08

is because it's generally seen as

11:10

hard science. This is the guy's brain.

11:13

But when we're talking about fMRI,

11:16

what we're looking at is the activity in the brain, and

11:18

we're generally asking something about the

11:20

person's mental state, and

11:22

can that be the same kind

11:25

of hard science. On the one hand,

11:27

it's a clear question with a clear answer

11:29

if someone has a stroke or a brain tumor.

11:32

But this isn't the case if you

11:34

want to pose a question like did

11:36

this defendant intend to

11:39

kill the victim? fMRI doesn't

11:41

and can't give you clear answers

11:44

like that to questions that are useful

11:46

for the legal system. So we're going to dig

11:48

into this now. So

12:03

first let's start with the question of

12:05

whether fMRI has

12:08

been used in courts. The answer is yes,

12:10

But the technology can be used in different

12:12

ways. It doesn't always have to involve an

12:15

individual's brain, but can sometimes

12:17

be about brains in general.

12:20

So let me give you an example. There was

12:22

a murder case in Missouri where

12:24

a young man named Christopher Simmons

12:27

broke into the home of a woman named

12:29

Shirley Crook. He covered

12:32

her eyes and mouth with duct tape,

12:34

he bound her hands together, and

12:36

then he drove her to a state park and

12:39

threw her off a bridge

12:41

to her death. Now, this was a

12:43

premeditated crime, and the evidence

12:46

was overwhelming, and he admitted to the murder.

12:48

So the judge and jury handed down

12:51

a death sentence. But

12:53

there was a complication. Christopher

12:55

Simmons was only seventeen years

12:57

old at the time he committed the crime.

13:00

And so this case spun all the

13:02

way up to the United States Supreme Court,

13:05

and the question was can you

13:07

execute someone who was under

13:09

the age of eighteen when they committed

13:11

the crime? After all, the argument

13:14

goes, adolescence is characterized

13:16

by poor decision making, and young

13:18

people should have the chance to grow

13:20

up into a different life. Well,

13:23

one of the things that happened at his trial

13:26

is that the Supreme Court considered

13:28

fMRI evidence. Now this wasn't

13:30

from Simmons's brain in particular, but

13:33

from adolescence in general.

13:36

The study compared young people

13:38

and adults performing the same cognitive

13:41

tasks, and what the researchers found,

13:44

not surprisingly, is that young brains

13:46

are not doing precisely the same thing as

13:48

older brains. There are measurable

13:51

differences. A juvenile's

13:53

brain just isn't the same thing as an

13:55

adult. So the Supreme Court

13:57

justices saw this evidence,

14:00

considered it, and presumably this is part

14:02

of what led the court to conclude

14:04

that it is unconstitutional to

14:07

execute someone for a crime who is a

14:09

minor. Now that's an example

14:12

of fMRI making it into the

14:14

court. It's been used in this way

14:16

to compare groups of people,

14:18

juveniles versus adults in this case.

14:21

But things get a little trickier

14:24

when you're trying to say something about an

14:26

individual's brain, the brain of

14:29

the one guy standing in front of the bench.

14:32

So what can we and can we not

14:34

say with the technology? So let's zoom

14:36

in on a few examples. Many

14:39

researchers and legal minds have been asking

14:41

whether one can use brain imaging

14:43

to diagnose whether someone has antisocial

14:47

personality disorder, which is a condition

14:49

in which a person has a long term

14:52

pattern of manipulating, exploiting,

14:54

and violating other people people

14:56

with antisocial personality

14:58

disorder or a SPD. They'll

15:01

commit crimes, they'll flaunt rules,

15:04

they'll act impulsively and aggressively,

15:06

they'll lie and cheat and steal. Now,

15:10

this is a condition that is massively

15:12

overrepresented in the prison population.

15:15

But biologically it's not obvious

15:18

what it's about. There's no single gene

15:20

here, and there's not a single environmental

15:22

factor. It's a complicated combination.

15:25

And the legal system often cares to know

15:28

whether someone has ASPD

15:31

or not. And so researchers started

15:34

to wonder a long time ago, could you use

15:36

brain imaging to determine

15:38

in some clear categorical

15:40

way, does this person have

15:43

ASPD or not. So, in

15:45

one study, researchers highlighted

15:48

the brain regions that had high

15:50

probability of being anatomically

15:53

different between people with

15:55

ASPD and those without. And you can

15:57

look in the cortex what's called the

15:59

gray matter, or below the core

16:01

text what's called the white matter, and you can

16:03

measure these small anatomical differences

16:06

between those with and without. So the question

16:08

arose, can you use this technology

16:11

in court as a diagnostic tool

16:13

to say that this person has

16:16

ASPD or not? Now

16:19

do you see any problems with this off the top of your

16:21

head about whether this technology

16:23

can be used. The problem is

16:25

that all the scientific results come about

16:28

from examining groups

16:30

of people, like fifty people in each

16:32

group, and the question is whether

16:35

these group differences are strong

16:37

enough to tell you about individual

16:40

differences. So this is known as the

16:42

group to individual problem. In

16:44

other words, you have data from

16:47

groups of people that can be distinguished

16:49

on average, but you're trying

16:51

to say something about this individual.

16:54

It would be like making an accurate

16:56

statement that men on average

16:59

are taught than women, and

17:01

then asking whether some individual,

17:04

like a tall woman, could be categorized

17:06

as a man because her height clocks

17:09

in at the average mail. The legal system

17:11

is well aware of this grouped

17:13

individual problem, and so as

17:16

technologies are introduced, the

17:18

justice system always needs to ask how

17:21

specific is this technology and how sensitive

17:24

is it? Is it good enough for individual

17:26

diagnosis. Brain imaging studies

17:29

generally just give us group average

17:31

results, and the question is whether

17:34

it tells us enough or anything

17:36

about the person who's standing in front

17:38

of the bench right now. Now.

17:41

The idea of bringing functional

17:44

brain imaging to bear on questions

17:46

of criminal behavior is an old one,

17:48

and this grouped individual problem

17:51

is just as old. For example, there

17:53

was a study in nineteen ninety seven where

17:55

researchers image the brain of

17:58

normal participants and murderers,

18:01

and they found, on average, there was less

18:03

activity in the frontal lobes

18:05

in murderers. So you

18:08

look at the activity in the front of the brain

18:10

behind the forehead and you say, hey, on average,

18:12

there's less going on here in the murderer

18:15

group. But you can't use this on an

18:17

individual. You can't say, oh, this

18:19

person has less activity, so he must

18:21

have been the murderer. In other words, it

18:23

has no power in a court of

18:26

law. You still face the problem of

18:28

trying to say anything about

18:30

an individual from a group average.

18:33

And so it's for reasons like this that

18:35

brain imaging on individuals

18:37

has not gotten very far in courtrooms.

18:40

Let me give one more example. Another research

18:42

group used brain imaging fMRI

18:45

to see if they could identify pedophiles.

18:49

They found twenty four pedophiles

18:51

and thirty four controls, and they

18:53

showed them images of naked

18:56

men and women and boys and girls. And

18:58

what they found is that they could on average

19:02

separate the participants who were pedophiles

19:05

from the participants who were not. In

19:07

other words, the pedophilic brain shows

19:09

a subtly different signature of

19:12

brain activity than the non

19:14

pedophilic brain when shown these

19:16

pictures. It turns out that heterosexual

19:19

versus homosexual seems to be distinguishable

19:21

as well. So you might think that

19:23

sounds quite useful for the legal system,

19:26

but when scientists and legal

19:29

scholars take a closer look, it's not

19:31

as clear. The first question is

19:33

what are these brain signals actually

19:36

measuring. The assumption is

19:38

that it's measuring a state of arousal,

19:40

like sexual attraction, but what else

19:43

might be going on? Well,

19:45

the difference in brain signals could be driven

19:47

by a stress response

19:49

or an anxiety response by the

19:52

pedophilic participants who know they're

19:54

being measured. Or perhaps

19:57

what you're seeing is a measure of disgust

19:59

by the non pedophilic group who

20:01

knows the purpose of the study and doesn't

20:04

like gazing at pictures of children in

20:06

this context. Or what if the

20:08

pedophilic participants were just

20:10

slightly more likely to avert their

20:12

eyes because of shame or

20:15

not wanting to get measured. That would

20:17

cause a statistical difference

20:19

in the brain signals and could, in

20:21

theory, explain the results. So

20:24

there are lots of things that

20:26

could yield this brain imaging

20:29

result of a difference between the two groups,

20:31

beyond the hypothesis that it's

20:33

just measuring arousal, So stress,

20:36

anxiety, discuss shame, all

20:38

these things might be what's getting

20:40

measured here. And part of why this matters

20:42

is because there are many brain imaging

20:45

measures where it turns out

20:47

it's easy to manipulate the results.

20:50

So let's say you are a pedophile

20:52

who doesn't want to be labeled as such. Can

20:54

you purposely move your eyes

20:57

whenever you see a picture of the children,

20:59

and that messes up the ability

21:02

of the scanner to measure something. If

21:04

something can be faked or messed

21:06

up, then the technology is useless.

21:09

But let's say, for argument's sake, that you have a technology

21:11

that can't be faked or manipulated,

21:14

and that allows us to move on to the second point.

21:16

Let's say you don't even care what's getting measured,

21:19

like stress or anxiety or whatever. All

21:21

you care to know is whether there is a

21:23

neural signature that can distinguish

21:25

the pedophiles from the non pedophiles, irrespective

21:28

of what is causing that signal. Well,

21:30

there's also a legal problem here, which is

21:32

that it's not illegal for a person

21:34

to be attracted to children. It is

21:36

only illegal if they act

21:38

on that. All that's illegal is

21:41

whether you have committed a crime

21:43

or not, not whether you are attracted

21:45

to children. So you can think about whatever

21:48

attracts you ostriches or

21:50

jello or whatever, as long as you

21:52

don't commit an illegal act.

21:56

So whether you're talking about ASPD

21:58

or murderers or pedophile while, you'll

22:00

see that measuring something that

22:03

matters for a court of law isn't

22:05

as straightforward as it might

22:07

have originally seemed. So

22:10

now let's return to the Palo Alto three

22:12

thousand. The question is just

22:14

because the company claims

22:16

that it functions, well, how do

22:18

you know whether or not to admit it into

22:21

the courtroom? After all, remember

22:23

what I said about the John Hinckley case,

22:25

how cat scans were admitted into

22:27

the court to argue that he had schizophrenia.

22:30

Well, it's now known that wide

22:32

and salsa in the brain have no relationship

22:35

to schizophrenia. There are other

22:37

better anatomical signatures that we have

22:40

now, like thinner cortices in the

22:42

frontal and temporal lobes and shrunkened

22:44

thalamuses. But it turned out

22:47

that the idea of white and salsa I

22:49

just didn't hold up. Now, there was nothing fraudulent

22:52

going on with the claim. It was just a new

22:54

technology at the time and they

22:56

were doing the best they could with small sample

22:59

sizes. But it turned out the

23:01

theory of white and sul sight was

23:03

scientifically unsound. Remember

23:05

how I mentioned that the judge went back

23:07

and forth several times about

23:09

the issue of whether to accept Hinckley's

23:12

cat scan into the courtroom. That's exactly

23:14

the right thing that should have happened. Not

23:17

all claims are going to be correct just because

23:19

a scientist says so. Despite

23:22

best efforts, science can often be

23:25

incorrect, and that is the

23:27

importance of the scientific method.

23:30

It's always knocking down its own walls.

23:33

So what is a court

23:36

to do about all this? Well,

23:38

let's say that someone wants to introduce

23:40

the Palo Alto three thousand into

23:43

a court case, and you are the

23:45

judge. You have expertise

23:47

in the legal system, but you don't know the details

23:50

of what's possible in neuroscience

23:53

and large language models, and you have

23:55

questions about whether this technology

23:58

should be admitted, questions about whether

24:00

it can accurately read people's

24:02

thoughts, So how do you decide

24:04

whether it should or should not be admitted.

24:21

So let's step back to nineteen twenty three.

24:23

There was a man named mister Fry who

24:26

said that he had developed a lie

24:28

detection technology and it

24:30

relied on a measure of your blood

24:32

pressure, and he wanted to introduce this

24:34

into a court case the

24:37

way you might want to get the Palo Alto three

24:39

thousand into a case. But it turned

24:41

out that mister Fry's claims were

24:43

not widely accepted by anyone

24:45

else in the scientific community, and

24:48

so on those grounds, the

24:50

court decided not to admit

24:53

it into the courtroom. What they said

24:55

was, look, we'll accept

24:58

expert testimony that comes from

25:00

well recognized science, but if there's some new

25:02

technology, it has to be

25:04

sufficiently established so that it's

25:07

gained general acceptance

25:10

in the field in which it belongs. In

25:12

other words, if other experts

25:14

in the field don't believe that

25:17

mister Fry's systolic blood

25:19

measurement is actually good at detecting

25:21

lies, then you can't admit it

25:23

as evidence in the court. And

25:25

that case set the bar for what came

25:27

to be known as the Fry standard,

25:30

which is that technologies need to

25:33

be generally accepted by other experts

25:35

in the field before they can be

25:37

admitted into the courtroom. So under

25:39

the Fry standard, the court would work

25:41

to determine whether the Palo

25:44

Alto three thousand has met

25:46

the general acceptance of the scientific

25:48

community. If science experts

25:51

around the world say, I've never

25:53

heard of this Palo Alto three thousand, I

25:55

don't think that it can actually work, then

25:57

you, as the judge, can

26:00

glued it from admissibility. So

26:02

the court solves the problem by

26:04

deferring to the expertise of other

26:07

people in the field. But this

26:09

isn't the only way to make that decision.

26:11

The Fry standard still is the rule

26:14

in about half the states in America,

26:16

but the rest use a different

26:18

rule to decide whether evidence

26:21

should be admitted, and this is called

26:23

the Dowbert standard. So in

26:25

nineteen ninety three there was a lawsuit from

26:27

a man named Jason Dalbert.

26:30

He was born with severe birth

26:32

defects and his parents brought

26:34

suit against Merrill Dow the pharmaceutical

26:37

company, and they said these severe

26:40

birth defects were caused by the

26:42

medication that the mother was on called

26:44

Bendicton. So the

26:46

pharmaceutical company said the birth

26:49

defects were not caused by this medication,

26:51

and it went to federal court and

26:53

Dalbert said, look, here

26:56

are animal studies showing that

26:58

this drug is related to birth defects.

27:00

And the pharmaceutical companies expert

27:02

witnesses got up and said, look, this

27:05

is not generally accept in the field because

27:07

these are just animal studies and there's no

27:09

conclusive evidence that

27:11

shows the link between these and humans.

27:14

So if you're the judge, how

27:16

do you know how to arbitrate this? It's

27:19

difficult. Right, here's some science from

27:21

the laboratories and here's the pharmaceutical

27:23

company saying it's not generally accepted in the

27:25

field that this causes birth effects. So

27:28

what do you do? Well, what happened

27:31

is the case was decided in favor of the pharmaceutical

27:33

company. So Dalbert took it on appeal

27:36

to the Ninth Circuit and the Ninth Circuit judges

27:38

also awarded this to the pharmaceutical company.

27:41

So Dowbert brought this case to the Supreme

27:43

Court, and the Supreme Court analyzed

27:45

this carefully, and what came out of this was

27:48

a new standard for when evidence

27:50

should be admissible, and that's known

27:52

as the Dalbert standard, and

27:55

the Doalbert standard says, look,

27:57

you accept expert testimony about,

28:00

for example, these labrat studies if

28:02

it will help the jury to understand the evidence

28:05

better or determine the fact

28:07

in issue. In other words, it doesn't

28:09

demand general acceptance

28:12

in the community. Under the Dalbert standard,

28:14

the key is just whether some piece

28:16

of evidence is relevant and reliable.

28:19

Now, the key is that the Fry standard

28:22

made the scientific community the gatekeeper,

28:25

but the Dalbert standard makes the

28:28

judge the gatekeeper. The judge gets

28:30

to say from the beginning that they'll

28:32

evaluate this and ask is

28:34

this evidence relevant and reliable?

28:37

Does it pass my bar for that? So,

28:39

regarding this hypothetical palo alto

28:41

three thousand, the judge might ask

28:44

has the technique been tested in actual

28:47

field conditions as opposed to just in a

28:49

laboratory. Have there been any papers

28:51

on the palab alter three thousand that were

28:53

published in peer reviewed journals? What

28:56

does the rate of error? Do

28:58

standards exist for controlling the

29:00

operation of the machine, and so on? These

29:02

are often difficult questions. It's not always

29:04

easy for a judge to make a decision

29:07

about whether or not to accept a new

29:09

technology. But this gives a pathway

29:12

where the judge is the gatekeeper.

29:14

So let's imagine for a moment

29:16

that the Palo Alto three thousand

29:19

passes the standard for admissibility.

29:22

Is there any reason why the technology

29:25

might still be excluded from

29:27

the courtroom. There is one reason.

29:29

Let's say that you're the defence lawyer

29:31

and you say, Gosh, this thing is

29:34

so stunning that it's going to

29:36

prejudice the jury because they're going

29:38

to look at this fancy technology, and

29:41

even in the absence of really good

29:43

evidence, they'll say, Wow, this

29:45

guy seems guilty. Let's send him to

29:47

the electric chair without considering

29:49

the other points. So

29:52

to prevent that from happening, there's a special

29:54

rule called Federal Rules of Evidence

29:56

four h three, and this just says

29:59

you you should exclude evidence if

30:02

what you can learn from it is substantially

30:05

outweighed by the risk of undue

30:07

prejudice. In other words, does

30:10

it sway the jurors more

30:12

than it should. So what you'll see in

30:14

courtrooms all the time is that if a lawyer

30:16

tries to exclude a piece of evidence

30:19

from being admitted based on let's say a

30:21

Doubert objection, but the evidence

30:23

gets past that, then the lawyer

30:25

is going to take a second bite at the apple

30:28

by calling on federal rules

30:30

of Evidence four three, saying, look,

30:33

even if this is relevant and reliable,

30:35

it's going to have too much sway

30:38

on the jury. So why is this

30:40

an issue? Are there technologies that

30:42

have undue sway on

30:44

jurors? Is that a concern? It

30:47

is? And this brings us back

30:49

to fMRI. In a

30:51

court of law where jurors

30:54

are your neighbors and your community

30:56

and probably not experts in neuroscience,

30:59

a lot of people will be swayed

31:01

by a colorful brain image.

31:03

They're going to put a higher weight

31:06

on this than maybe they should, and possibly

31:08

at the cost of not weighing this evidence

31:11

appropriately in the context of

31:13

the whole case. And this is part

31:15

of the concern that some legal scholars

31:17

have, and this has come to be known as

31:20

the CSI effect. So

31:22

you remember the television show CSI.

31:24

This stood for Crime Scene Investigation,

31:27

and it's a television drama about a team of

31:30

forensic scientists and detectives

31:32

in Las Vegas who use cutting

31:34

edge scientific techniques to solve

31:37

murders. So they go around

31:39

each week and meticulously gather and analyze

31:42

evidence from crime scenes and each

31:44

episode features a complex

31:46

case with an intricate puzzle and the

31:48

CSI team has to solve this

31:51

to bring the criminals to justice. Well,

31:54

the idea with the real life

31:56

CSI effect is that jurors

31:59

come to expect what they've seen on

32:01

TV in terms of magical

32:03

machinery that does something

32:06

like you hit a button to enhance

32:08

the picture and then the computer enhances

32:10

it, and they see everything with clarity, where

32:12

the plot twist requires that the

32:15

investigator pull out some magical

32:17

technology that suddenly solves the crime,

32:20

or looking at the pedophile's brain with neuroimaging

32:22

and knowing whether he did the crime or not. So

32:25

jurors have come to expect this sort of

32:27

thing because you don't spend

32:29

all your time in a courtroom if you're not a lawyer,

32:32

and something like the television

32:34

show CSI is their only window into

32:36

that world. The problem

32:38

is that it often turns out to be a false

32:41

window, and when researchers do

32:43

studies on this, they generally find that

32:46

jurors see neuroimaging

32:48

as the truth of the matter asserted.

32:51

So we just spent a minute on

32:53

looking at the claim that you can measure pedophilia

32:56

and we noted that the brain signals might

32:59

represent that you're a pedophile, or

33:01

it might represent stress or anxiety,

33:03

or disgust or shame or averting the

33:05

eyes or all kinds of things. But that kind

33:08

of nuanced analysis doesn't usually

33:10

get done, and so neuroimaging

33:12

often comes to be interpreted by the

33:14

jury as the truth of the

33:17

matter asserted. This is what scholars

33:19

sometimes call the fallacy of

33:21

neurorealism, and the fallacy is

33:24

just that what you see in these

33:26

pretty false color images is the

33:28

truth. In other words, somebody thinks,

33:30

oh, you're capturing the moment

33:33

of pedophilia in its raw form

33:35

there whereas, of course, the truth is

33:37

that fMRI signals are not

33:40

direct proof of the experience

33:42

itself. As a side note, these

33:44

questions of bringing visual

33:47

evidence into the courtroom, they're not unique

33:49

to brain imaging. They've been around for a long time.

33:52

It goes back at least to X

33:54

rays. So when X rays got

33:56

introduced in the eighteen nineties, they

33:58

immediately started showing up in court

34:01

and everybody was absolutely blown away

34:03

by the idea of being able to

34:05

see inside of a body.

34:07

It's like magic. So what happened

34:09

over a century ago is people asked

34:11

this question of can we use this as evidence

34:14

in court? And the judge said

34:16

at the time, as long as it was scientifically

34:19

reliable, it could be introduced.

34:21

But the same questions about influence

34:24

on the jury came up, because there's a

34:26

real power to seeing

34:28

something. And of course what

34:31

we have currently with brain imaging

34:33

is even a deeper issue because

34:35

it touches on all our notions of

34:37

being human. For example,

34:39

I saw a cover of a Time

34:42

magazine a while ago and the title

34:44

read what makes us Good

34:47

or Evil? And the cover image

34:49

was a huge picture of a brain

34:51

scan, and there was a little picture

34:53

of Mahatma Gandhi with a pointer

34:56

to a part of the brain. And there was a little picture

34:58

of Adolph Hitler with a pointer to

35:01

a different part of the brain. And

35:03

in case you haven't heard my other episodes on this,

35:05

I want to make it clear there is no such thing.

35:08

You can't measure some spot in

35:10

the brain to determine whether

35:12

someone is good or evil.

35:14

And by the way, Friedrich Nietzsche

35:16

wrote about this over a century ago, the

35:19

words good and evil don't

35:22

even represent something fundamental,

35:24

but instead these words end up getting defined

35:27

by your moment in time. What is

35:30

good right now may be seen as

35:32

evil in a century. These terms

35:34

are defined by your culture.

35:37

What you think is good might be seen as sacrilege

35:40

by another group. So the idea

35:43

that you could just measure something in the brain and

35:45

say whether the person is good or evil

35:47

really makes no sense. However,

35:50

millions of people see this kind

35:52

of Time magazine cover, and this

35:55

is why legal scholars worry that

35:57

brain images could be

35:59

persue of past the point that

36:01

they should be in the legal

36:04

argot. This is known as something having undue

36:07

influence. Brain images are influential

36:10

because they take some abstract

36:13

issue like evil intent and

36:15

seem to nail it down to

36:17

the physical. So this is why

36:20

something like Federal Rules of Evidence

36:22

four h three plays an important

36:25

role in asking whether

36:27

something has undo influence,

36:29

whether it sways people more

36:32

than it should now. At the extreme,

36:34

some people say functional brain

36:37

images should never be allowed in the

36:39

courtroom because of their influence. One

36:41

solution that a colleague of mind suggested

36:44

is that you ban the visual

36:46

aspects of brain images from the courtroom,

36:49

so you just have expert witnesses come on to

36:51

the stand and tell you what they

36:53

think is going on as best they can. But

36:55

they're verbally presenting the results, not

36:57

showing them. But these are tough issues,

36:59

right because you can show a gory

37:02

photograph from a crime scene, which

37:04

can also prejudice an entire courtroom.

37:07

Or you can show a reenactment

37:09

of a murder, but if you can't show

37:11

a brain scan, that seems like

37:13

maybe a double standard. So should you

37:15

rule out all visual images

37:18

or allow everything? And

37:20

if you heard episode nineteen, I

37:22

talked about eyewitness testimony

37:25

and how massively swaying that

37:27

is to jurors. You can have all

37:29

sorts of expert scientific testimony,

37:32

but then you have the person get up on the stand

37:35

with tears and a cracking voice and say,

37:37

I don't care what they say. I know that's the

37:39

guy. And we're all moved and influenced

37:42

by that, even though eyewitness testimony

37:44

is so deeply fallible. So

37:47

this is all just to say that the question of undue

37:50

influence always has to be

37:52

asked. Compared to what compared

37:54

to other technologies, compared

37:57

to gory photographs of the

37:59

crime scene, compared to acting

38:01

out a rape scene or a murder scene, do

38:04

those unduly sway a jury?

38:07

So I hope what you see is that These are tough issues,

38:10

perhaps tougher than you

38:12

had intuited at the beginning of the episode,

38:14

So let's wrap up. We

38:17

often think that when a new technology

38:19

comes along, like a new brain technology,

38:22

it always gives useful information,

38:24

and we might assume that courts start leveraging

38:27

it right away. But there are complexities

38:29

around this. For example, in an

38:31

earlier episode, I talked about lie detection. How

38:33

do you know when somebody is actually lying? There

38:36

are lots of technologies that try to measure

38:39

some version of this, but nothing

38:41

can simply tell you the answer because

38:43

the whole concept of a lie is

38:45

complex. Sometimes you might be

38:48

telling the truth but you're factually incorrect,

38:50

for example, because you're honestly

38:53

misremembering how something went, but you

38:55

believe your memory. Or for someone

38:57

else, they might have no associated

39:00

stress response because they just don't care

39:02

that they're lying. So when somebody comes

39:05

to the courts and says, hey, I have a

39:07

new lie detection technology,

39:09

the judge can't just say great,

39:12

bring it to the case, because the judge first

39:14

has to decide whether it should

39:16

be admitted or instead, whether

39:19

its promise will sway

39:21

the jurors more than its value.

39:24

We're all enthusiastic about the next

39:26

stages of technology and being able

39:28

to make important measures about

39:30

what's happening in the brain. But the

39:33

legal system has to be very careful

39:35

about this, whether by standards

39:37

of general acceptance in the scientific community

39:40

or by the choice of the judge's gatekeeper.

39:44

Each new technology has to be weighed

39:46

carefully for admissibility every time

39:49

before it can enter the esteemed

39:52

halls of justice.

40:00

Eagleman dot com slash podcast. For

40:02

more information and to find further

40:04

reading, send me an email at

40:06

podcast at eagleman dot com with

40:09

questions or discussion, and check

40:11

out and subscribe to Inner Cosmos

40:13

on YouTube for videos of each episode

40:16

and to leave comments Until next

40:18

time. I'm David Eagleman, and this is

40:20

Inner Cosmos.