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Can MRIs Help Solve Crimes?

Publication Date: 
May 14, 2010
National Public Radio (NPR) - Talk of the Nation
Paul Raeburn

Professor Hank Greely talks to NPR's Paul Raeburn on the ethics of using fMRI scans in the courtroom:

That's the flute, and that means we're switching to another subject and another guest. And as promised, neuroscience and the law.

At least two companies now claim that they've developed a brain scan that can tell you whether you are lying. You can't get away with it anymore, at least according to what they say.

Here's how it might work. You get arrested for a crime. No, nobody who listens to SCIENCE FRIDAY gets arrested for a crime, but somebody gets arrested for a crime. You say you are innocent. And in order to prove it, you are willing to undergo a brain scan. It's like a modern lie detector, but it's far more high-tech than those old things with all the wires and the, you know, the pen wiggling on the scrolling graph paper. I kind of like those things. But this is high-tech stuff. This is neuroscience.


Professor HENRY GREELY (Stanford Law School): Well, my pleasure, although I'm not guaranteeing that I'm giving you all the answers.

(Soundbite of laughter)

RAEBURN: I'm trying to box you in a corner here before we get started.

Prof. GREELY: Yes, yes, no, C, and all of the above.

RAEBURN: Right. Spoken like a lawyer, what can I tell you? So anyway now, some of these companies that have talked about this are claiming these high accuracy rates. Do you believe them?

Prof. GREELY: No.

(Soundbite of laughter)

Prof. GREELY: No. Although in fairness there are now over 20 peer-reviewed published studies that find a statistically significant correlation between certain patterns of brain activation seen on fMRI and - when people, who are experimental subjects are saying something deceptive. So there is some scientific basis for thinking that there may be something to be found there. I don't think it's nearly proven enough to use in court or anyplace else where we rely on it. And I think the very high accuracy rates being portrayed by the companies are just wrong.

RAEBURN: Now, what is your background in this area? You're a lawyer. Did you -do you specialize in this particular neuroscience law intersection?

Prof. GREELY: Yes, in the last eight years, since 2002, most of our work has been on legal issues in neuroscience. I've been a co-director of the Law and Neuroscience Project funded by MacArthur Foundation. And I'm one of the directors of the Neuroethics Society, which is a scholarly organization devoted to looking at the ethical, legal and social implications of neuroscience on our society, which we think are going to be enormous.

RAEBURN: Now, I have to be at the AAAS session - the American Association for the Advancement of Science session in February. I guess it was in San Diego where you were the prosecutor in a mock trial...

Prof. GREELY: Okay.

RAEBURN: ...looking at neuroscience in the courtroom. They put on your - have you been a prosecutor?

Prof. GREELY: I am not. I was a lawyer. I'm a recovering lawyer. I'm, you know, 25 years into my recovery.

RAEBURN: You dont admit to being a lawyer any longer.

Prof. GREELY: I keep my license up but I'm not sure why.

(Soundbite of laughter)

RAEBURN: Okay. So, in any case, tell us a little bit about that case. That was a little bit different from lie detection as I recall.

Prof. GREELY: Yeah.

RAEBURN: What was the issue there? What were you trying to demonstrate as the prosecutor?

Prof. GREELY: Well, there are a couple different things going on, but that case was an example of where defense - criminal defendant was saying there's something unusual about my brain. That means you really shouldn't hold me responsible for my actions. So we created a mock case. It was the AAAS representatives who did most of the work on it, Deborah Runkle and Mark Frankel.

We created a mock case and then had a couple of lawyers, a real judge and a couple of real neurologists as expert witnesses. The theory was that this person had a problem in his frontal lobes that meant that he wouldn't had been able to form the intent to commit a murder, that he wouldn't had been able to premeditate, and that's what we argued in that particular case.

There are lots of different ways you can make these arguments about brain defects or brain problems leading to limited responsibility. You could try to argue that it's evidence for an insanity plea, it's evidence that the person is incompetent to stand trial, it's evidence that they couldn't form the right intent - ots of different arguments that can be used. It's probably come up most often, though only one so far with fMRI. Most of it has been structural MRI. In capital cases, where after the defendant is found guilty, there's a separate hearing to decide whether or not he should receive the death penalty or life in prison, brain scans have been used in those cases for a long time.

RAEBURN: So this is - there's a lot at stake with the accuracy of these things and the admissibility?

Prof. GREELY: Yeah.

RAEBURN: Lives are at stake if it's used in sensing procedures.

Prof. GREELY: Yes. And if it's used in guilt and innocence issues, how many years in prison is not a good thing for an innocent person to have to go through. So there's a - when you move this to the courtroom, the stakes are much, much higher than they are when you're rounding up the usual subjects, the undergraduate psych majors for an experiment in your lab.

RAEBURN: Now, as the prosecutor in that mock trial, you argue that the brain scan evidence should not be admitted that the person was guilty.

Prof. GREELY: Correct. Well, the brain scan evidence shouldn't be admitted, both because there wasn't enough of a scientific basis for it and because, even if there was, it was not legally relevant to that particular legal question. The law may care that whether you've got the intent to do something, and may care about whether you're insane and whether you're competent, but the law doesn't particularly care whether you had brain damage or not. Lots of peoples' brains are unusual. Everybody's brain, in some detail, is different from everybody else's. You've got to show something awfully strong and, I think, often through - much more frequently through behavioral evidence and through scanning evidence about a defect. But these cases are happening.

I'm part of a group that's looking for all the cases in California courts in the last three years that have involved neuroimaging evidence in criminal cases, and we've found about 25 to 30 of them so far.

RAEBURN: And what's - what has been - what are the outcome has been on those cases or how is the evidence been used?

Prof. GREELY: Well, we haven't full analyzed all of them. One of the things we've discovered is getting documents out of court clerks is a lot harder than most other things we've tried to do.

RAEBURN: I know a lot of reporters who would be sympathetic on that score, actually.

(Soundbite of laughter)

Prof. GREELY: Yeah. Yeah. My best research assistant is a law student who used to be a reporter and...

RAEBURN: Is that right?

Prof. GREELY: ...had been working very well on this.


Prof. GREELY: But we found that they've - they have had very mix success rates. They seemed most frequently to be used, or thought to be used, in the most serious cases, the murder cases, particularly those where capital punishment is an issue. And sometimes, they look like they may have been somewhat effective and other times not.

RAEBURN: Okay. And so it's a developing area of the law. Has anybody established any procedure yet for using these things?

Prof. GREELY: You know, not really. There isn't a great deal of agreement on what counts, what would be - what kind of a brain scan image would really indicate strongly something that would be of legal relevant. So, you know, we're still at very early days. I don't know how big a deal this will end up being in the law. I think the people who are involved in it from the legal side disagreed to some extent on how important to legal matter this will be.

I frankly think the more interesting and potentially important stuff will be the kind of lie detection or other kinds of mind reading that fMRI let us do. You know, one example that we don't think about very often - it's not very sexy but it's very important in the law - is pain. Whether somebody is having pain or not, and if so, how much, is a huge issue in lots of civil trials, usually not criminal cases. But everything from auto accidents, to workers compensation cases, to Social Security disability determinations. And there are neuroscientists who are beginning to think they can see pain in the brain. That could really revolutionize a lot of court cases.

We havent seen it introduced in court yet. At least I havent. But I know that at least one friend of mine has been was hired as an expert witness to testify about this, and the case had settled before it went to trial.

So between looking for pain, looking for deception, looking for evidence, whether or not a witness has remembered something by looking at brain scans, all these are going to, I think, raise major issues for the legal system.

And soon, in fact, just today, this morning, a hearing ended in Jackson, Tennessee, about whether an fMRI-based lie detection report should be admitted into evidence in the criminal case. We don't have an answer yet. The judge will make a decision - make a recommendation to the district court judge sometime in the next couple of weeks. But this is a very real issue. It's on us now.

RAEBURN: Let me take a pause to say I'm Paul Raeburn.

And this is SCIENCE FRIDAY from NPR.

So you've obviously got your tentacles out there. You're on top of these things, that this just happened this morning, and you're already aware of it.

Prof. GREELY: Well, it's been a pretty exciting time. There was this as far as we can tell, this is only the second time an argument has been made that fMRI-based lie detection should be allowed into court. The first time was last week, a case in Brooklyn - a civil case where the trial court judge decided not to allow the evidence in.

The difference between that case and this case is that in Brooklyn case, the judge did it without hearing any scientific evidence. He didn't rule on whether the evidence - whether the scientific method was reliable or not. He just said that in his view, it shouldn't be allowed to go to the credibility of the witness as that was the role of the jury.

In this federal case in Tennessee, though, there were expert witnesses, both trying to convince the judge that the reports should be admitted and trying to convince him that there wasn't enough science to back it up and it shouldn't be admitted. So this is a case to watch very closely.