A 10th-Grader's Stomach Lie Detector Test

Trisha Pasricha's 10th-grade science fair project, a lie detector test that measures changes in the stomach to determine whether the subject is telling the truth — won second prize at the 2005 Intel International Science and Engineering Fair. Madeleine Brand speaks with the 16-year-old about her research, and her conclusion that a lie detector test based on activity in the stomach is more accurate than traditional tests.

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MADELEINE BRAND, host:

And finally today, the stomach never lies. That's the theory behind a new lie detector test that measures the stomach's electrical activity. Its creator is 16-year-old Trisha Pasricha, and she joins us now.

Trisha, I think you were a high school sophomore when you created this test. Why did you decide to create a new lie detector test?

TRISHA PASRICHA (Lie Detector Test Inventor): Well, I did a project in seventh grade that involved various visual stimulants on heart rate and when I asked my father, who's a gastroenterologist, how stress affects the stomach, he said it changes the electrical rhythms. And then I started thinking about my mother's profession, which is as an engineer in the FBI, and she used to tell me a lot about polygraph testing that she used to work with. And so, when you put the two together you get a lie detector for the stomach.

BRAND: So she worked with the traditional lie detector test, which measure increased heart rates and sweating, and you thought, `Well, why not try out a similar test with the stomach?'

PASRICHA: Yeah, because no one has ever tested using the stomach before, and the current polygraph is only about 90 percent accurate and there is definitely a want for improvement.

BRAND: So how does yours improve on the traditional lie detector test?

PASRICHA: Well, speculatively it can raise that percentage. A lot of talk has been that since it involves the electrical rhythm of the stomach, a lot of countermeasures that people can take might not be as effective to control the electrical rhythm of the stomach. And, of course, I'm sure there's going to be some people who will maybe figure out a way to control the stomach's activity, but it should be more difficult.

BRAND: So tell us how yours works.

PASRICHA: Well, basically I--it involves using the--an electrogastrograph, which is abbreviated as an EGG. You use it by hooking up six electrodes to the surface of the stomach and you pick up on the electrical rhythm and it measures any change.

BRAND: So when people lie, they have an increased electrical rate?

PASRICHA: Well, what actually happened was that when people lie, the normal rhythm of two cycles per minute went into a stage called arrhythmia where there was no set pattern.

BRAND: Could you also describe the test that you did, that you undertook?

PASRICHA: Oh, sure. Basically I gave all the subjects a set of playing cards and I showed them a computer screen with different pictures of playing cards and made them lie about which cards they had.

BRAND: And what did you find?

PASRICHA: I found that everyone's electrical rhythm did change, some to different degrees than others. And I also found that when we were doing EKGs, which is for the heart rate, the heart rate increased for both lying and truth telling, which is I think a big problem with a polygraph is that sometimes it's difficult to determine if it's because they're lying or simply nervous.

BRAND: So what has been the reaction in the, I guess, the lie detector world? What do they say about your test?

PASRICHA: There's been a lot of positive feedback. There's some people who are still skeptical, which is very understandable because it's only been 15 subjects, but a lot of people do agree that many more subjects need to be tested. And that's what I'm hoping I will get funding for.

BRAND: This whole experience of you creating this and the interest that it's garnered, what does that mean for you? Are you going to now follow in your father or mother's footsteps and become a gastroenterologist or work with the FBI?

PASRICHA: Well, I've been thinking I'm definitely going to go to med school, and probably gastroenterology is good or infectious diseases. But the FBI is very fascinating. So I'm not really sure right now.

BRAND: So I understand that you're cutting class today.

PASRICHA: Yeah, I had to cut class this morning.

BRAND: To do this interview?

PASRICHA: Yeah, there's been a lot of media things that we just finished up. And I had a physics test so it worked out nicely for me.

BRAND: So what did you tell your school you were doing?

PASRICHA: I'm haven't really told them anything yet, but I think I'm going to have to get back to them.

BRAND: You're going to tell the truth, right?

PASRICHA: Of course.

BRAND: Well, Trisha Pasricha, thank you very much.

PASRICHA: Thank you.

BRAND: Trisha Pasricha is a high school junior in Houston, Texas. She created a new lie detector test that measures the stomach's electrical activity.

I am not lying. DAY TO DAY is a production of NPR News with contributions from slate.com. I'm Madeleine Brand.

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