JOHN DANKOSKY, HOST:
And now it's time for the Video Pick of the Week, and Flora's here. Hi, Flora.
FLORA LICHTMAN, BYLINE: Hi, John.
DANKOSKY: So what do you have for us?
LICHTMAN: This week, we have a Valentine's Day special, getting ready for next week's Valentine's Day, in case you didn't remember.
DANKOSKY: How romantic.
LICHTMAN: Yes, of course, always on SCIENCE FRIDAY.
DANKOSKY: Yeah.
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LICHTMAN: So, you know, maybe you're in the situation you have a special someone, but you're not sure if he or she reciprocates. Well, science may be able to help. Gaze deeply into that person's eyes, and while you're doing it, just try to measure their pupil size.
DANKOSKY: Really? Measure their pupil size. Why is that?
LICHTMAN: Well, I mean, you also may want to ask them.
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LICHTMAN: So the - what I learned this week is that studies have shown that our pupil will dilate in response to strong emotions, it turns out, and other things, too - so increase cognitive load. So when they've asked people to memorize a long string of numbers or concentrate on something, or stress will dilate your pupils a little bit. And it's kind of...
DANKOSKY: Hosting a talk show, maybe.
LICHTMAN: Yeah, your pupils look a little dilated.
DANKOSKY: You get those - huge right now, yeah.
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LICHTMAN: Yeah. And when you're interested in things, too, your pupils will dilate. And so I spoke with Bruno Laeng, who's a psychologist at the University of Oslo, and he is kind of a champion of this methodology (unintelligible).
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DR. BRUNO LAENG: And if you know Italian, actually, you know already why it's called belladonna, which means pretty woman. It's because men would find it very attractive. And then a woman would talk to them with this very large pupils, because it looked like you're intended suitor was so interested in you.
LICHTMAN: And you heard him right there.
DANKOSKY: There he is.
LICHTMAN: There he is, magically appearing. I don't know.
DANKOSKY: How did that happen?
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LICHTMAN: I don't know. Anyway, so what Bruno Laeng was talking about there was this plant called belladonna. And in - there's a folklore goes that, in the Middle Ages, women would put drops of this plant - which by the way is poison, so do not try this at home...
DANKOSKY: Do not try that at home either, yes.
LICHTMAN: ...into their eyes and their pupils will dilate. And it turns out that, you know, apparently, men found this attractive - according to the myth, anyway. So there's some evidence that not only does - do our pupils dilate when we're feeling strong emotions, but that also we respond to it. And there have been studies showing that, actually, we find people with dilated pupils more attractive, for example.
DANKOSKY: But what of this idea that her beauty is like the sun? I mean, that would make your pupils go the other direction, right?
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LICHTMAN: Yeah. If her beauty was like this, then your pupils would get really small. So maybe if she were radiant, your pupils will get smaller, but hers would be still big. I'm not sure quite how to parse that...
DANKOSKY: Well, I think, as you said earlier, Flora, probably if you're going to stare across the table at someone at Valentine's Day, you should ask before you just stare directly in their pupils.
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LICHTMAN: It's a little creepy, yeah.
DANKOSKY: It is a very romantic video. Thank you very much.
LICHTMAN: Yeah. Check out the video. It's on our website. You can see some very up-close-and-personal shots of eyeballs...
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LICHTMAN: ...which a pretty cool. Some tips for Valentine's Day.
DANKOSKY: Yeah, and a little bit scary, too. Thanks so much, Flora.
LICHTMAN: Thanks. Transcript provided by NPR, Copyright NPR.