Brain Imaging: Deception

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Brain Imaging: Deception




Guest:  Dr. Mark George – Psychiatry & Behavioral Sciences

Host:  Dr. Linda Austin – Psychiatry


Dr. Linda Austin:  I’m Dr. Linda Austin.  I’m interviewing Dr. Mark George who is Professor of Psychiatry, Neurology and Radiology here at the Medical University of South Carolina.  Dr. George, you’ve done some very interesting research recently in the area of brain neurophysiology, the science of deception.  It’s a big topic, obviously, but what point of view have you addressed this from?


Dr. Mark George:  I’ve been interested in whether we could use brain imaging to figure out when people are lying.  For a long time, when I was at the NIH (National Institutes of Health) back in the early 1990s, some people from the CIA came and asked me if you could use brain imaging to figure out when people are lying.  I looked at him and said, “No way.”  Back then, we were still very crude.  But the idea kind of stuck in my head.  So, as the field has progressed and we’ve gotten better at taking more refined pictures, I’ve kept it in my mind. 


I started with the idea that when we’re lying, we’re really doing about three things that are different.  When you tell a lie, you have to remember that you’ve told a lie, so you’ve got working memory; you have to remember the lie.  For most people, when they tell the truth, that’s their default.  So, when you’re telling a lie, you have to kind of stop what you would normally do and go in a different direction.  So, there’s working memory.  There’s kind of a differential route.  And some people, although not all, get more anxious when they lie.  That’s the basis of the polygraph.

So, as the field of looking at working memory and multitasking, and anxiety, and imaging kind of grew, I said, well, I think it’s about time that we put that together and see whether we might be able to use imaging to figure out when people are lying.


Dr. Linda Austin:  Now, you’ve mentioned the word imaging, and you’re talking about brain imaging, there are a number of ways of doing that.  What is the technology that you use to do that? 


Dr. Mark George:  Currently the most powerful thing that we have is called magnetic resonance imaging, MRI.  And most people are familiar.  They have MRIs of knees or whatever.  They’re very common.  The MRI scans that we use look at changes in blood flow.  So, when a different part of your brain is doing something differently, like when I’m talking, the language areas get more blood flow.  So we can kind of image, very sensitively, subtle changes in blood flow.  So we’re really looking at blood flow changes as a function of what your brain is doing, with MRI.


Dr. Linda Austin:  When you actually got around to, after several years, looking at your hypothesis that maybe the brains of people lying would look different, what’d you find?


Dr. Mark George:  We started slowly.  We have people commit a little crime and then lie about it.  First of all, we wanted to look at whether the brain was different when you’re lying versus not, at a group level.  That’s the state of the art for many of our imaging tools.  We can figure out, at a group level, whether a group is different.  But that doesn’t help me when I want to know whether you, Dr. Austin, are lying to me at this moment.  So, what we had to do was move beyond group statements to within individual statements of prediction.  And that’s what we want to do in therapy.  I want to be able to see whether this person has a disease, this person, today, and maybe make statements about their prognosis.  And so I got re-interested in lying, really, because it was a nice lab study to force us to figure out how to do within individual statements that have predicted power.  I said if we can do this with lying, then we figure out those tools and use them back in therapy, which is where I’m most comfortable.  So we’ve been doing that.  And it works.


Dr. Linda Austin:  I’m interested in hearing how you set up the experiment.  What was the crime that you had people commit?


Dr. Mark George:  Well, the one that we started with is pretty simple.  We put people in a room and we have, hidden in the room, two objects, either a ring or a watch.  We instruct to go in there, steal one of those two.  Don’t tell us which one.  They take whatever it is that they’ve stolen, put it in a locker.  And, inside the scanner, we tell them to lie to us, and if you can effectively lie to us, we’ll give you more money.  So we ask them a series of questions:  Did you steal the watch?  Did you steal the ring?  Are you from South Carolina?  You know, we have some neutral questions in there.  And, based on the blood flow changes during their responses, and we’ve now done, maybe, five studies, we have about a 90 percent accuracy level in terms of figuring out which one of those two you stole.


Dr. Linda Austin:  Was your original hypothesis correct?  Are there really three different things going on when people are lying?


Dr. Mark George:  Yeah.  It was kind of interesting.  So, we’d know the regions involved in the behaviors I talked about, so that’s where we looked initially.  We did a different kind of analysis where we put all the information in the computer and we said, we don’t care about these regions in particular.  We want you, computer, to just look at the differences and see what’s the most powerful way of predicting.  And, interestingly, those regions that we had been talking about came out in this non-direct approach.  What is the least predictive, interestingly, are the brain regions involved in anxiety, which is, I think, why the polygraph is not so good.  It measures peripheral anxiety when you sweat or your blood pressure changes.  Some people can lie pretty good without getting anxious.  So it looks as if the brain imaging can kind of get around that and look at, actually, real brain activity, not just peripheral measure of anxiety.


Dr. Linda Austin:  What was the best predictor that you found?


Dr. Mark George:  Well, we don’t have one region that’s better than others.  We put them all together in a little model.  And that’s what gives us the power.


Dr. Linda Austin:  And how many regions altogether are different when somebody is lying?


Dr. Mark George:  In our current models, about four different regions.


Dr. Linda Austin:  And those four regions are associated with what functions?


Dr. Mark George:  Working memory, if I’m trying to remember my grocery list when I’m going home, or you give me a phone number and I don’t have a place to write it down; I’m working on that, or multitasking, if I’m trying to do several things at one time, talk and eat a peanut butter sandwich and, also, solve another problem.


Dr. Linda Austin:  So, working memory.  What else?


Dr. Mark George:  There’s working memory and then this multitasking, doing several things at once.  And then the orbitofrontal cortex, which is right above the eyebrow, seems to be activated probably because of this issue that most people’s default is to tell the truth.  So, you’re having to stop an action and go with another.  And we know that the orbitofrontal cortex is involved in inhibiting kind of over-learned responses.  So, if you do a task called a go/no-go task where you start doing something and all of the sudden you have to switch and stop it, your orbitofrontal cortex lights up.  So I think it’s kind of a break in the brain of a normal brain.  Those are the regions that are predictive.


Dr. Linda Austin:  So, is that two on each side, is that what you meant by four?


Dr. Mark George:  Right.


Dr. Linda Austin:  I see.  Okay.  What do you see as the potential practical applications of this?  Is this something that we’ll be able to use to see if the dog really did eat the homework, or why hubby didn’t come home from work?  Where are you going to go with this?


Dr. Mark George:  Well, as I said, the reason I got interested in it was really more neuroscience and pushing the technology.  And now I want to use that for diseases.  It’s interesting to watch where it might go.  There are two companies that have now been formed.  MUSC has a patent, and I’m named on that, but I’m not really involved in the translation.  In the government, there are a lot of people who undergo polygraph screening to get certain jobs in the Defense Department where they have special information.  So, one idea would be to use it in a screening tool for a certain job placement.  You know, you’d have to say, have you ever stolen, or have you ever been a member of the KGB? 


Another area is in the legal arena where so much of law depends on who’s telling the truth.  I could easily see where one person is saying something and the other person is saying the other, they go inside a scanner, and then that information would be part of the discovery process.  I don’t think we’ll ever get as strong as genetic testing, which is 99 percent effective.  But we’re already 90 percent, and I think it will improve.  So, I think it could clean up a lot of frivolous law suit cases.


Dr. Linda Austin:  Now, in the area of law, though, it’s pretty well known that sometimes people lie, obviously, but other times people are just mistaken.  They have false memories; they misremember, inaccurate memories.  Have you done any research looking at that?


Dr. Mark George:  Those are fascinating questions.  As I just described, what we’ve done so far is this little simple lab study, and you go right in the scanner, right afterwards.  And although there’s money on the table, you’re not going to prison.

You’re not going to lose your child; you’re not going to lose your job.  So, it remains to be seen what happens when you have more time between when you did something and when you’re asked the questions.  So, do these memories change over time?  Or, when there’s more in jeopardy, you know, when you really are

shaken, does it still work?  We don’t know yet.  I think the way that this works is if you firmly believed that you did something, the test would say that you did it.  So, if you really had a false belief, the test would corroborate your false belief.  And that might be a way to get around it, where you truly convince yourself that you did other than what you did.


Dr. Linda Austin:  So fascinating.


Dr. Mark George:  Although there’s a paper, actually this week, where they’re actually looking at beliefs and disbeliefs, and false beliefs.  I don’t know where it will go.


Dr. Linda Austin:  Dr. George, thanks so much for talking with us today.


Dr. Mark George:  Thank you.


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