[RADIOLAB INTRO]

JULIE MOSS: Who's the gentleman we're on the air with?

ROBERT KRULWICH: Oh, there's gonna be two of us. So one of them is named Jad. That's not me. His name is Jad. Like his parents call him Jad.

JULIE MOSS: Jad?

ROBERT: But it's Jad, really.

JULIE MOSS: Had they been drinking?

ROBERT: [laughs] No, they're Lebanese.

JULIE MOSS: Oh, sorry.

JAD ABUMRAD: So we're gonna begin the show with this delightful duo.

JULIE MOSS: I'm Julie.

JAD: Julie Moss.

WENDY INGRAHAM: I'm Wendy.

JAD: Wendy Ingraham.

JAD: Hi, Julie. Hi, Wendy.

JULIE MOSS: Hi Jad.

WENDY INGRAHAM: Hi Jad.

JAD: They've been friends for a really long time.

WENDY INGRAHAM: Remember that one time you bought all that ...

JULIE MOSS: Everything in a tube?

ROBERT: [laughs]

JAD: They—they both like to travel. They both like to shop. And they both like to run really long distances until they collapse, usually in front of millions of people. Now, Wendy ...

JULIE MOSS: Wendy was a classic athlete from day one.

JAD: Who was apparently born this way.

JULIE MOSS: Her mother tells me how she had to channel her energy into sports.

WENDY INGRAHAM: Yeah. I always considered myself a science project.

ROBERT: What do you mean?

WENDY INGRAHAM: We—we've been created. We have hands, feet. We have a mind. We have lungs. We have a heart. Let's see what it can do.

JULIE MOSS: Wendy, we're very opposite in that—in that respect.

JAD: Julie—Julie is an entirely different story. And we're gonna tell you that story in just a moment. But first, we should say this is Radiolab. I'm Jad Abumrad.

ROBERT: And I'm Robert Krulwich.

JAD: Our topic today is limits. The limits of ...

ROBERT: ... the body. Let's start there.

JAD: Then the limits of the brain.

ROBERT: And finally, the limits of what we can know about everything.

JAD: Julie, how did you get interested in this race that you're about to tell us about? Was it like a ...

ROBERT: Like an impulse or something?

JULIE MOSS: Well, no. It was a requirement to graduate. I had—I had to do a—it's called a senior—senior project. I went to Cal Poly-San Luis Obispo in California. And I—I was a PE major, which now I ...

JAD: Like Phys Ed, you mean?

JULIE MOSS: Yeah. And I—that was just by default. I was a California surfer girl. I started surfing at 14, but I needed a senior project. And there I was in 1981, watching TV instead of studying. And on comes ABC Wide World of Sports.

[ARCHIVE CLIP, ABC Wide World of Sports: This is ABC Wide World of Sports, brought to you by Anheuser Busch Natural Light.]

JULIE MOSS: The Ironman, from Hawaii. And I watched it, and it just sucked me in.

JAD: This must have been like really early Ironman.

JULIE MOSS: Oh, yeah. I think it was the fourth one, and I thought, "It's in Hawaii. It's great. I know my mom will pay for it because I have to do this project for school." And so I started doing research on it.

ROBERT: And this, just so we know, this is you—you swim, you bike, you run. That's the order?

JULIE MOSS: You swim 2.4 miles, you ride 112 miles, and then you run a marathon.

ROBERT: Wow!

JULIE MOSS: So it was ...

JAD: But wait a second, though.

JULIE MOSS: Go ahead.

JAD: That seems like a major decision to want to go 140—I mean, were you a triathlete type person at that point in your life?

JULIE MOSS: No.

ROBERT: [laughs]

JAD: Had you ran a marathon before?

JULIE MOSS: No. It was conceptual. Those were just the distances. Those were numbers. That wasn't reality. It was just you were in Hawaii. By the time I got off the plane to do the Ironman, I still hadn't completed the total distance that I'd need to do on the bike or the swim.

ROBERT: Oh my God!

JAD: Wow!

JULIE MOSS: But I wasn't going over there to be competitive. I was going over there to do this event, have fun in Hawaii, and then I'll write up some sort of bogus, you know, physiological consequences or something. But I really just—I thought I was taking the easy way out.

ROBERT: When you got off the bus or you walked into the room where the other ones were, did you suddenly think, "Uh-oh"

JULIE MOSS: Yeah. I mean, people were taking it very seriously. People had coordinated outfits and I thought, "I'm feeling a little like the country mouse," you know? So I think when race day rolled around, it was—it was sort of my day to get through and never do again. I mean, it was really this is a one-time thing.

ROBERT: So shall we run the race?

JAD: Yeah. So, okay. Let's just—you do the first two legs, the swimming and then the biking. And then what?

JULIE MOSS: I'm doing really well. You see me on the bike, I'm riding along. I mean, from the old coverage of ABC, I'm smiling at the camera. I'm certainly not in an aerodynamic position. Why would you want to be all crouched over when you could be sitting up smiling?

ROBERT: That was your beauty queen turn? "Hello!"

JULIE MOSS: I was doing parade waves. I really was. Loving the attention, and I had a Snickers bar early in the bike ride, and I keep thinking if I'd only eaten that Snickers bar instead of throwing it away. ABC came up on a camera and there I was trying to open this melted Snickers bar with my teeth, and all of a sudden there's a camera and it's like, "Oh my gosh, I don't want to be messy on national TV!" So I ditched this—this beautiful Snickers bar and, you know?

JAD: Okay. Skipping to the third leg of the race, Julie's through the swim. She's through the 112-mile bike ride, on to the marathon.

JULIE MOSS: I came off the bike. They told me, "There's a woman ahead of you." And she was a top-notch cyclist.

JAD: Oh, so you were in second place?

JULIE MOSS: Yeah.

ROBERT: Whoa, whoa, whoa, whoa, whoa! How did that happen?

JULIE MOSS: I was—I was doing really well. And I started on the run, and the one gal who had had a great bike ride had an Achilles injury. And sure enough by I think about eight miles or so I caught her. And there I am in the lead.

JAD: Wow!

JULIE MOSS: And all of a sudden, it was a little—things started to shift. I'm—I'm good at something. And somebody is trying to take it away from me, and that was the woman who was in second place, Kathleen McCartney. And even though she was a mile away, it felt like she was breathing down my neck and trying to take something that now I was becoming very attached to. I was also starting to fall apart physically.

JAD: What were those early signs?

JULIE MOSS: Cramping, and a feeling that you weren't digesting your food. That everything was sort of sitting there sloshing around. Wendy's laughing. This is a serious moment and she's laughing about this. Like, mmm ...

JAD: In any case, finally Julie makes it to the last little itty bitty stretch of the race.

JULIE MOSS: Probably about—oh, about 400 meters from the finish.

JAD: And she's still in first place.

JAD: So Julie, let's do this. I'm actually, as we're talking, I'm watching you on YouTube.

JULIE MOSS: Oh, stinker!

JAD: I just wanted to take me into your head in these final moments, because it's—it's just—like, it's unwatchable, but you can't turn away.

JULIE MOSS: Yeah, it's a train wreck.

JAD: So I'm looking at you now, and you're running and it's dark.

JULIE MOSS: Mm-hmm.

JAD: There's people, like, on both sides cheering you.

JULIE MOSS: Mm-hmm.

JAD: And so you're running, and then you're slowing down. Then you're really slowing down.

JULIE MOSS: Mm-hmm.

JAD: And then you're walking a little bit like you're on stilts. And then right here your legs give out.

JULIE MOSS: They give out. And I couldn't get back up. I mean, I thought, "Get up," and my legs wouldn't work. So I actually—I just sort of laid there on the ground, and I figured out if I put my arms in front of me and leaned on my arms, they would sort of form like a tripod, and I could sort of lean on my arms, and kind of got one leg up and one leg up and and kind of staggered to a walk and started walking again.

JAD: All right, now you're walking again, but you're like ...

JULIE MOSS: Drunk monkey.

JAD: Yeah. Really wobbly.

JULIE MOSS: Yeah.

ROBERT: Now all this time you're conscious that number two is getting closer and closer? Are you—are you conscious of her at all?

JULIE MOSS: Oh, yeah. Oh, yeah. And I had to keep finding a way to keep going. And my thought was, "This is mine!"

JAD: Oh, you just fell again.

JULIE MOSS: Oh, yeah. Yeah.

JAD: See, this is the one that gets me right here. You fall down and it's—and your arms go back. It's like you're dying.

JULIE MOSS: Yeah. And as I was putting one hand in front of the other, I saw this—this pair of tennys go by and these legs. And I thought, "That's her. She's gone by me." And it was just—I just thought, "I quit." I just thought—I can't say it on National Public Radio, but, "F it."

JAD: Yeah.

JULIE MOSS: "F it." And all of a sudden there's this voice that just said, "Get up. Get up. Just keep moving forward." I could see the finish line about 10 feet in front of me and I thought, "Get up." I cannot—I can't get up again. I really. I—"Get up." Do not think. I've sort of worn out that tactic. "Get up." But I can crawl.

[ARCHIVE CLIP: Look at this! Oh my gosh!]

JULIE MOSS: And I crawl. And so here I am coming along and—and the TV camera lights are blinding me, and ...

WENDY INGRAHAM: And no one's helping her.

JULIE MOSS: My life was going to be different. I mean, I felt my life changing. I made a deal with myself. A deal was struck. And I don't care if it hurts, I don't care if it's messy, I don't care how it looks, I would finish. I would finish. I would finish.

JAD: So Julie Moss crawls the last 10 feet of the race, literally an inch at a time. And that whole time, the cameras are on her and they capture everything. And I mean everything.

JULIE MOSS: Yeah. I—I pooped my pants on national TV. It doesn't get more shameful from that. Wendy teases me all the time. "You know, you were a chocolate mess. You know, one way or the other."

WENDY INGRAHAM: "You can get up here and do this next thing."

JULIE MOSS: Yeah, but it was—it was a pivotal moment in my life.

JAD: And to this day, Julie says, the person she is now, it all began with ...

JULIE MOSS: That voice that—that I hadn't ever called upon that just said, "Keep moving forward."

ROBERT: But that's the thing that gets to me is like, it didn't say to you, "You can't!" It—it actually said exactly the opposite.

JULIE MOSS: Isn't that cool?

JAD: I would have thought it would have said, "Stop. Come on!"

ROBERT: Yeah. "That's what you look like. Lie down. Lie down!"

JAD: "Enough!"

JULIE MOSS: That's your ego. That's your ego that will come in and sabotage your real self. There is no limit. You know, I really believe that.

ROBERT: You do?

JULIE MOSS: And I just—I absolutely do.

JAD: No limit.

JULIE MOSS: No. Nope. No. Yeah, no. [laughs]

JAD: Let's take seriously what Julie Moss said, that there are no limits. I think she meant psychologically.

ROBERT: Yes. I mean, there are obviously limits if she ...

JAD: Well yes, but ...

ROBERT: She could die.

JAD: You could die.

ROBERT: Yeah.

JAD: But short of that, you would say it is her muscles that are determining the limits, right?

ROBERT: Exactly. And the cell, your muscle cell.

JAD: Yeah. Let's just question that for a second.

ROBERT: [laughs]

JAD: Let me introduce you to a guy. His name is—what's his name?

LULU MILLER: David Jones.

JAD: His name is David Jones.

DAVID JONES: Hi. Hi.

JAD: That's him. He's a retired physiologist.

DAVID JONES: At Metropolitan University.

JAD: And he's got a slight condition that interferes with his speech, just so you know.

ROBERT: Okay.

JAD: Anyways, he did a study—two studies, actually, that involve bikers.

DAVID JONES: These are experienced cyclists.

JAD: He'll have these people ride stationary bikes for really long distances.

DAVID JONES: Yeah.

JAD: All the while, he'll shoot their muscles full of sugar, like with an IV.

DAVID JONES: And you can actually get extremely high levels of glucose in the blood.

JAD: How much? Like, a whole energy drink's worth of sugar straight into their blood?

DAVID JONES: More than that. Probably—probably several energy drinks.

JAD: Oh!

JAD: Now theoretically, if it's your muscles that are controlling how far and fast you bike, you should get this injection and just be like—pew!

DAVID JONES: They should be performing miracles. That's right.

JAD: But it never works.

ROBERT: It never works?

JAD: Yeah. The people who have sugar in their muscles do the same as people who don't.

DAVID JONES: That's right.

ROBERT: Wait, does it work at all?

DAVID JONES: It made absolutely no difference in their performance.

ROBERT: Whoa! Bad news for sugar.

JAD: And what it suggests is that our muscles have way less to do with our limits than we think. Which raises the obvious question: what is making the difference?

ROBERT: Hmm.

JAD: So now I'm gonna tell you about this second study, which I completely, like, find mind blowing, although it's a hard study to summarize, but I'm gonna try.

ROBERT: Okay.

JAD: So you with me?

ROBERT: I'm with you so far. You haven't started yet, though. That's always a good place to be.

JAD: I need your full participation and interest.

ROBERT: Okay.

JAD: Okay. So he does a study where he puts a bunch of bikers on bikes and he has them pedal a lot.

DAVID JONES: It's about 40 kilometers.

JAD: Long distance.

DAVID JONES: Yeah.

JAD: Now he's got two groups. Each group gets an energy drink.

ROBERT: Mm-hmm.

JAD: Which they sort of have to drink ...

ROBERT: While biking.

JAD: While biking. Except they don't drink it. The rule is they don't actually drink it. They just swish it in their mouth.

DAVID JONES: And spit it out.

ROBERT: Swish and spit.

JAD: That's right. That's what they do. Swish, spit, bike. Swish, spit, bike.

ROBERT: Well, I wouldn't want to be the towel guy in this particular experiment.

JAD: Well, apparently they have scientists with buckets who just stand next to them.

DAVID JONES: And they spit into the bucket.

ROBERT: Okay.

JAD: So half the people get real energy drink to swish and spit.

ROBERT: Yep.

JAD: Half the people get fake energy drink to swish and spit.

DAVID JONES: And they both taste the same.

JAD: And nobody knows who's getting what.

DAVID JONES: It's a double-blind experiment.

JAD: So you would think in this scenario that nobody should get any benefit from this because no one's actually drinking the drink. Nothing's getting into the body.

ROBERT: Mm-hmm.

JAD: Or let's say, like, the taste creates a placebo effect? Well, then everybody should get the placebo effect equally.

ROBERT: Everybody should get it.

JAD: But here's the thing: only the people who swished—swished, not drank, but swished the real energy drink got a boost.

ROBERT: Oh!

JAD: How much of a boost?

DAVID JONES: It's a minute to a couple of minutes.

JAD: Whoa, that's a lot!

DAVID JONES: Yeah. And minutes. That's the difference between, you know, finishing first and last.

JAD: Yeah.

ROBERT: So let me think here, but don't say anything for a minute.

JAD: Okay.

ROBERT: Let me just think about this. So maybe something in the first set of athletes who got the real drink, something inside them knew something.

JAD: Yeah! Here's the big theory. You want the little theory or the big one first?

ROBERT: Well, I'd like the big theory briefly.

JAD: Okay. The big one briefly. There's an idea that's been floating around for a while. It's called the Central Governor Theory, which is that inside your head there's this little circuit, which they're starting to see on brain scans, there's this little circuit that governs your energy supply. And when it feels like you're in danger of running low, it'll trigger signals of pain to be sent to your body to try and get you to rest. Now what scientists are finding is that this governor circuit is really conservative. It'll send your pain to try and get you to stop way before you are out of juice.

ROBERT: So if you were a fuel tank, they would flash E, E, E for empty.

JAD: But you got a quarter tank left. So what might be happening with these bikers is that the sugar is landing on their tongue. The tongue sees the sugar, sends a message to the brain. The governor sees this message and says, "Oh, we're about to get some energy, then it's okay for you to spend some energy. And let me just give you some for my secret stash over here." And so you feel a boost.

ROBERT: So the conjecture here is you have a reservoir of extra stuff, but it is so deeply disguised that you can't even know that it's there.

JAD: Exactly. And to skip to the punchline, when you feel tired, Mr. K ...

ROBERT: Mm-hmm?

JAD: Not just tired, when you are dead.

ROBERT: Spent.

JAD: When you are spent ...

ROBERT: Yeah.

JAD: ... which does not feel like a subjective thing at all, that feels like an objective reality. You are done. Well, in fact, at that moment, maybe you're not. Maybe you're just feeling the effects of that little governor lying to you.

ROBERT: Oh!

JAD: Which raises the question: what if you could lie back to her? Then how far could you go?

ROBERT: Hmm.

JAD: So with all that in mind, we're gonna kick it up a notch. Let me tell you about this competition called The Ride Across America. It should really be called The Ride Into the Hellfire Depths of Despair.

ROBERT: [laughs]

JAD: But we're gonna call it The Ride Across America.

ROBERT: Didn't have quite the zing that the sponsor wanted. "Ride into the depths of despair with Wrigley's Spearmint Gum."

JAD: We heard about this first from a reporter named Daniel Coyle.

JAD: So what is the Ride Across America?

DANIEL COYLE: It is—basically it's an insane event. You get on a bike in California, and you bike across the country 3,000 miles, the equivalent of four Mount Everests. And they don't sleep.

JAD: At all?

DANIEL COYLE: No, they will sleep. They'll sleep an hour a day, two hours a day.

ROBERT: An hour a day?

DANIEL COYLE: Yeah.

ROBERT: So if—if this is a 10-day race, they will sleep for 10 hours over the full length of the race?

DANIEL COYLE: Yeah, it's a race that is designed to reveal what human limits are.

ROBERT: Who—who does it? Can you describe the kinds of people who are attracted to this?

DANIEL COYLE: No, I think they come from all walks of life. They come from all over the globe. It's a really interesting cross-section.

JAD: We actually got curious about this, so we sent our producer, Lulu Miller, to track down a few of these guys.

LULU: Two guys.

JAD: Who'd you find?

LULU: Well, the first one ...

PATRICK AUTISSIER: Yes.

LULU: ... his name is Patrick.

PATRICK AUTISSIER: Patrick Autissier. I'm 47 years old from France.

LULU: He's the rookie.

LULU: Had you done any kind of long distance cycling before?

PATRICK AUTISSIER: No. No, none at all.

LULU: He's actually a scientist.

PATRICK AUTISSIER: Biologist, yeah.

LULU: Got a wife, two kids.

JAD: Okay.

LULU: And then we've got the champion.

JURE ROBIC: Okay. Hello. Jure here.

LULU: So this is Jure Robic.

JURE ROBIC: Hello.

LULU: He's won this thing four times.

JURE ROBIC: On the back it's a killer. My body, it's֫—I can go also in the rain or cold or the heat.

LULU: His job is he's a soldier.

JURE ROBIC: Employed by the Slovenian army. What else? What would you like to know?

LULU: Okay, 2005.

PATRICK AUTISSIER: So it's—to start with it's 7:00 am in San Diego. Starts at nine.

[ARCHIVE CLIP, Ride Across America event: You gonna win this year?]

LULU: Is it like 20 people, or a hundred people?

PATRICK AUTISSIER: 25, I think.

LULU: So the tape you're hearing right now is actual footage from that day.

[ARCHIVE CLIP, Ride Across America event: Let's go Patrick!]

LULU: Turned out the year he did it there was actually a film crew there following every single rider.

PATRICK AUTISSIER: And so I was—I mean, really scared. I mean, scared at him.

LULU: Not Jure, though.

JURE ROBIC: No.

LULU: He's just in front of Patrick.

JURE ROBIC: I really—how to say in English, I'm really sure in myself.

LULU: [laughs]

[ARCHIVE CLIP, Ride Across America event: Four, three, two, one! [cheering]]

PATRICK AUTISSIER: Then the race is on.

JURE ROBIC: It's easy. You just start your engine and go.

PATRICK AUTISSIER: But for me, and since I didn't know what to expect, I was riding very conservatively at the back of the pack.

LULU: 14 states. 3,000 miles to go.

DANIEL COYLE: They don't go very fast. They'll cross the country going about 13, 14 miles an hour, which any 11 year old can ride for a time. The difference is that they just don't stop.

LULU: Seven hours later, California desert.

PATRICK AUTISSIER: It's really hot.

[ARCHIVE CLIP, Steve Todey: My watch says 109 degrees. We're in the shade in the car.]

LULU: This is Steve Todey, the camera guy following Patrick in a van.

[ARCHIVE CLIP, Steve Todey: Patrick's out here climbing a hill.]

PATRICK AUTISSIER: I've never experienced this kind of temperature. I mean, 110 Fahrenheit.

LULU: Then, 150 miles later ...

PATRICK AUTISSIER: Arizona. Rolling hills, sunset.

LULU: 200 miles. 300 miles.

JURE ROBIC: Then the sun is rising.

LULU: 400 miles, 500 miles.

PATRICK AUTISSIER: Utah, it's still very hot.

LULU: And then ...

PATRICK AUTISSIER: Colorado. The mountains. The big mountains.

LULU: Jure's in the lead. He's just crested the top of a 12-mile climb.

JURE ROBIC: It was during the middle of the night. It was just raining, really heavy raining.

LULU: And he begins to coast downward.

JURE ROBIC: Descending without pedaling. And after two kilometers, I was completely frozen, shaking like I was electric.

PATRICK AUTISSIER: Your butt is like a hamburger.

LULU: Oh!

JURE ROBIC: Yeah. [laughs]

PATRICK AUTISSIER: I mean, it's all red. You don't have any skin at all.

LULU: Ow!

DANIEL COYLE: I mean, the bike is the most efficient machine for creating suffering ever invented.

ROBERT: [laughs]

DANIEL COYLE: The pressure is your hands. The pressure is on your neck.

LULU: This is this British guy named Chris Hopkinson halfway through the race, and his neck has just given out.

DANIEL COYLE: People whose necks have given out will take duct tape and literally tie their heads up. They'll put a cord to the back of their helmet and then pin it, say, to their belt.

JAD: Jesus, God!

DANIEL COYLE: So that they can look because they can—they can no longer hold their heads up.

[ARCHIVE CLIP, Chris Hopkinson: Oh God.]

JURE ROBIC: The pain is like waves, you know? And I—I don't know why it's there, but it is. It's like waves. It's coming and it's going, it's coming and it's going.

JAD: So Lulu, assuming that the central governor circuits inside the heads of all these riders are creating those waves of pain ...

LULU: Yeah.

JAD: How do they soldier on? How do they ignore it?

LULU: Well, I asked them that, and they each sort of have different techniques. So Patrick, he'll just start shouting back at it.

JAD: Literally?

PATRICK AUTISSIER: Yeah. Yeah, exactly.

LULU: And Jure? Well, he gets his crew to come up alongside him and blare Slovenian war songs.

JURE ROBIC: Through the speakers. Yeah, very loud, man.

JAD: Is that what we're hearing?

LULU: It is. This is him on his bike during the race singing along. And all of this works for a while, but then they hit the halfway point.

PATRICK AUTISSIER: Kansas. I don't know if you've been to Kansas.

LULU: Never. No.

PATRICK AUTISSIER: Don't live there. It's awful.

LULU: The scenery gets really monotonous.

PATRICK AUTISSIER: Then you don't have any sightseeing, nothing.

LULU: And more than that, they've gone over a thousand miles without sleeping, basically.

DANIEL COYLE: And that's where we see the sort of really interesting stuff start to happen.

LULU: It's here that we can catch a glimpse of the hidden potential of the human body.

DANIEL COYLE: If you've done everything, if you've handled the heat and hydration, if your infrastructure is solid, all the stress goes to the last point, which is the mind.

PATRICK AUTISSIER: It came very suddenly. It was dark. I were in a forest, and very quickly the environment got very aggressive.

LULU: He said he saw shadows running across the road. It looked like the trees were trying to reach out to get him.

PATRICK AUTISSIER: I was starting to have nightmares, but it was awake.

LULU: These kinds of hallucinations are just a fact of the race.

DANIEL COYLE: People seeing secret code in the cracks of the road, riders jumping off their bikes to square off and fight mailboxes.

LULU: And it's what breaks a lot of people.

JURE ROBIC: Yeah. [laughs]

LULU: But strangely, these kind of hallucinations might be the very key to Jure's success.

JURE ROBIC: I saw everything. I mean, a lot of, like, monsters. Like, zombies are gonna attack you, you know?

JAD: And why would that help him?

LULU: Well, think about why the central governor is in place.

DANIEL COYLE: The system is designed to always keep an emergency stash of energy there for you should you ever need it.

LULU: So those feelings of pain are really just a way of safeguarding that last ...

DANIEL COYLE: Little stash of energy that you could use if you absolutely had to.

JAD: Yeah. Like if your life was on the line or something.

DANIEL COYLE: That's right.

LULU: But what if you were convinced, and therefore your central governor was convinced, that your life really was on the line? That year when Jure got to Ohio ...

DANIEL COYLE: He—he hallucinated that there were Mujahideen, sort of Afghan horsemen chasing him.

JURE ROBIC: Yeah. With a gun, with a shotgun. And I said to my crew chief, "They are shooting at us! Come on, come on, do something. We are soldiers. Do something to these guys. They're attacking us."

DANIEL COYLE: The interesting thing about that is the way in which his team sees him hallucinating Mujahideen, and their reaction is, "Oh yeah, we see them too."

JURE ROBIC: "Come on, Jure. You might escape!"

JAD: Wait, why?

ROBERT: Because they're gaining on us.

DANIEL COYLE: They're gaining on us.

JURE ROBIC: It's funny, you know. But for me, it was not funny.

DANIEL COYLE: They will use his hallucination as—as fuel, and they make no bones about it.

MATJAZ PANINSEK: And when you see that ...

LULU: That's Matjaz Paninsek, Jure's crew chief.

MATJAZ PANINSEK: When you see him riding that fast after five or six days, almost dying on the bike, and then suddenly he explodes, your hair on your arm will go up, on your neck will go up. And then, you know, that's—that's why we are there, because you don't want to miss that moment because this is something out of this world.

LULU: Jure says that during the hallucinations ...

JURE ROBIC: I mean, the pain is gone.

LULU: Does it go—does it go away completely?

JURE ROBIC: Yeah.

LULU: But the trade off is that when he watches videos of himself like this, punching mailboxes and throwing his bike into a ditch, he says it's actually painful to watch.

JURE ROBIC: You know, it's really tough for me to look at myself in these videos, in these films, how do I—my behavior is going.

LULU: The reality is he's looking at a mad man.

JURE ROBIC: It's not me. That's—that's not me.

LULU: Yeah.

JAD: See, now I'm thinking, like, Daniel, like, if madness is the key, right, to tricking your central governor into giving you access to that energy, does that mean that if Robert and I went mad in that particular way, that we would suddenly be really athletic? I mean, are there actually seriously cases like that?

DANIEL COYLE: Well, there was actually—in the early 1900s, there was a doctor named Auguste Beer who noticed a mental patient making a leap in an asylum. And he measured the leap, and it compared rather favorably to the world record at the time.

JAD: What?

DANIEL COYLE: Yeah. And he was one of the early sort of propagators of this governor theory that obviously this patient from whom all the sort of governors have been lifted was capable of a feat of astounding strength.

JAD: All right. So Lulu, what happened at the end of the race?

LULU: Well ...

[ARCHIVE CLIP, Ride Across America event: From Slovenia ...]

LULU: ... Jure wins.

[ARCHIVE CLIP, Ride Across America event: ... Jure Robic! [cheering]]

JURE ROBIC: I won the RAAM. That's—that's something.

JAD: And what about Patrick?

LULU: Well, let's rewind a couple days. He's just crossed the halfway point in Mount Vernon, Kansas. And he decides to hop off his bike, take a quick break. And he's in the van. He checks his email.

PATRICK AUTISSIER: Just to give me some motivation.

LULU: And he sees an email from one of his friends.

PATRICK AUTISSIER: He said, "We're so sad that the Dr. Breedlove accident."

LULU: Patrick had no idea what this guy was talking about, but it appeared to suggest that one of the 25 riders, a guy named Dr. Bob Breedlove, had just been hurt.

PATRICK AUTISSIER: And so I asked one of my crew member what happened with Dr. Breedlove, and he said, "Well, he got in an accident and he died."

LULU: On the race? During the race?

PATRICK AUTISSIER: Yeah. Mm-hmm. And so when—when he told me this, I mean, immediately I was—I was—I mean, I was I mean, not only shocked, but I was done.

[ARCHIVE CLIP, Steve Todey: I understand, Patrick. I feel bad, too. Obviously, I feel bad.]

PATRICK AUTISSIER: And so, Steve Todey, the cameraman tried to—to push me.

[ARCHIVE CLIP, Steve Todey: But it would be pointless to stop here where you have a wide shoulder, a van right behind you.]

[ARCHIVE CLIP, Patrick Autissier: Who's going to call Anne-Cecile and tell her, "Oh, well, sorry, but—but Patrick just fell down the road and so he's hospitalized." Or even—even—even worst. I have kids and I have a wife. I went—I went too far on this race.]

[ARCHIVE CLIP, Steve Todey: I understand, Patrick. But how far is it to the next time station? Why don't we go there? Take another ...]

[ARCHIVE CLIP, Patrick Autissier: No, I'm dead, I don't want to continue that. That's—that's okay. I don't want to continue that.]

[ARCHIVE CLIP, Steve Todey: I'm just saying let's not throw in the towel just yet.]

PATRICK AUTISSIER: So after that, I mean, I started riding again, but for them.

LULU: Yeah.

PATRICK AUTISSIER: It was a magical night. It's very, very warm. A beautiful night, no clouds, nothing.

LULU: And as always, his crew is cheering him on, trying to pump him up.

[ARCHIVE CLIP, Ride Across America event: You're strong!]

[ARCHIVE CLIP, Steve Todey: Patrick, can I ask you why you're doing this?]

[ARCHIVE CLIP, Patrick Autissier: What?]

[ARCHIVE CLIP, Steve Todey: Can I ask you a question? Or don't you want to talk? Why are you doing this?]

LULU: But he's not saying anything back for hours. And then around one in the morning, Patrick says his mind just goes quiet.

PATRICK AUTISSIER: Completely silent.

LULU: Out of that silence, he said he heard a voice that said simply ...

PATRICK AUTISSIER: "You stop. Stop." And so that's what I did. I said, "I'm done."

[ARCHIVE CLIP, Steve Todey: You're done? You what?]

[ARCHIVE CLIP, Patrick Autissier: I'm done with my race. I'm done. You asked me a question earlier. You remember? Why I was doing that?]

[ARCHIVE CLIP, Steve Todey: Yeah. Why were you—why are you doing it?]

[ARCHIVE CLIP, Patrick Autissier: Because I just wanted to test my limit. Physical limit and mental. And I touched twice this limit, yesterday morning and—and this morning, and I don't want to live that again.]

PATRICK AUTISSIER: And I quit. And that's it.

ROBERT: Huh. I'm trying to figure out who I would honor more.

JAD: Yeah.

ROBERT: The winner of the race, or the man who insisted on losing.

DANIEL COYLE: I'm 40. I've got kids. I identified more with the guy who stopped.

JAD: Yeah.

ROBERT: Yeah.

JAD: But I think also, you see the guy who wins, and it makes you ask big questions about what's possible, you know?

ROBERT: Yeah. Like, how do you do that?

JAD: Yeah, I don't know that I would want to be that guy or even hang out with him. I like the second guy.

ROBERT: I know I'd like the second guy. I don't know.

ROBERT: Dan, what do you think?

DANIEL COYLE: I find myself looking at both of them, kind of with my jaw on the floor.

JAD: Daniel Coyle's latest book is called The Talent Code. And thanks, Lulu.

LULU: Yeah, and a huge thanks to Stephen Auerbach, who made the film Bicycle Dreams. That's where all this footage came from.

[WENDY INGRAHAM: Hey, Michael, this is Wendy Ingraham, and I apologize, I have a pretty bad cold. Radiolab is funded in part by the Alfred Sloan Foundation, the National Science Foundation.]

[JULIE MOSS: This is Julie Moss, Radiolab is produced by WNYC and distributed by NPR.]

JAD: Hey, I'm Jad Abumrad.

ROBERT: And I'm Robert Krulwich.

JAD: This is Radiolab. Today, our topic is limits.

ROBERT: Limits.

JAD: Limits.

ROBERT: Yep. How far can you take your—your body? We've done that.

JAD: We yeah—we've exhausted that.

ROBERT: I think so. So let's go uptown.

JAD: Yeah.

ROBERT: To the limits of the brain, to tackle just a piece of that question. Let's just take a look at memory.

JONAH LEHRER: Okay. All right, great.

ROBERT: And we're gonna do that by telling a story.

JAD: A story that we heard from Jonah Lehrer, you know, a frequent guest on the show, author of the books Proust Was a Neuroscientist, How We Decide.

ROBERT: And the story begins in a small town in the old Soviet Union back in the 1920s.

JAD: And it's about a newspaper reporter named Mr. S—at least that's what we're gonna call him.

JONAH LEHRER: Yeah, so Mr. S is a newspaper reporter. And one day his boss starts yelling at him because his boss gives out these assignments, talks to the whole newsroom, and he notices that Mr. S never takes notes. And this drives his boss crazy because his boss is, you know, saying all these things they have to report on, and Mr. S just never writes them down. And so his boss calls him to his office and says, "Are you lazy? Do you not take this job seriously?" And Mr. S responds, "Well, I just remember it all."

ROBERT: And the editor says, "Come on!" And he sort of quizzes him. He says, "What did I assign you yesterday?"

JONAH LEHRER: And his boss gives him this quiz, and sure enough, he remembers everything.

ROBERT: He remembers everything the editor said word for word. And the editor's thinking, "I don't know what's wrong with this guy. I mean, he's not a great reporter, but he has something queer going on in his head. So he decides to send him to a famous medical doctor in Moscow. A.R. Luria.

ROBERT: Who is Luria?

ELKHONON GOLDBERG: Luria—well Luria is a classical figure in neuropsychology and in psychology in general.

JAD: And who is this?

ROBERT: Tell us your name.

ELKHONON GOLDBERG: Elkhonon Goldberg. I'm a clinical professor at NYU Medical School.

ROBERT: Goldberg knew Luria.

ELKHONON GOLDBERG: Luria was my mentor. I worked very closely with him.

ROBERT: Not only was he a student of Luria's, Luria gave him a present once.

ELKHONON GOLDBERG: This is this book. The book about—the original book about this.

ROBERT: This book is one of the great works of early neuroscience.

ELKHONON GOLDBERG: Given me by Luria. That's him there.

ROBERT: Oh! So we're going to the right guy! You have an autographed copy by the guy.

ROBERT: It is a beautiful and almost novelistic description of what happened to Mr. S.

ELKHONON GOLDBERG: And the original title was A Little Book About Big Baby.

ROBERT: Yeah, what is it in Russian?

ELKHONON GOLDBERG: Маленькая книжка о большой памяти.

JAD: Okay. So Jonah, this guy, Mr. S, goes to this psychologist Luria. Now what does Luria do with him?

JONAH LEHRER: Luria, during the book, talks about how he wrote random numbers on a blackboard.

ROBERT: Numbers like 1-8-6-4-3. About 50 numbers.

JONAH LEHRER: And asks Mr. S to remember them.

ELKHONON GOLDBERG: Okay, here we are on page 16. S would study the material on the board ...

ROBERT: For about three minutes.

ELKHONON GOLDBERG: Close his eyes. Open them again for a moment.

JONAH LEHRER: "Okay, done."

ELKHONON GOLDBERG: And with that would re-log the series precisely. 6-6-8-0-4-3-2-1.

JAD: Wow. That's like a superpower!

JONAH LEHRER: Yeah. And this impresses Luria. He says ...

ROBERT: So he takes it up to the next level.

JONAH LEHRER: Then Luria gives him, you know, this—this—this incredible assortment of memory tasks, you know, everything from memorize Dante's Inferno to ...

JAD: Memorize Dante's Inferno? The whole thing?

ELKHONON GOLDBERG: No, no.

ROBERT: Well, not the whole thing, just the opening stanzas, mostly.

ELKHONON GOLDBERG: Nel mezzo del cammin di nostra vita, Mi ritrovai per una selva oscura ...

ROBERT: But here's the really weird thing. Mr. S does not read Italian, speak Italian. He had no idea what he was talking about. And yet the thing he memorizes, he gets word perfect.

JONAH LEHRER: Yeah.

ROBERT: And not only that, he was tested 15 years after he'd memorized those stanzas, and he still got it right.

JONAH LEHRER: Yeah.

ROBERT: Oh, wow!

ELKHONON GOLDBERG: He remembered everything. He had ...

ROBERT: When you say everything, what do you mean by it?

ELKHONON GOLDBERG: I mean everything, okay? So if he—suppose he interviewed you 10 years ago, he would have remembered the color of your sweater, whether you held the mic in the left hand or in the right hand. He would have remembered everything. I mean everything.

JONAH LEHRER: Luria never talks about a computational limit on Mr. S's memory.

ELKHONON GOLDBERG: "As an experimenter, I soon found myself in the state verging on utter confusion, and I simply had to admit that the capacity of his memory had no distinct limits."

JAD: How can there should be no limits? Because I'm thinking about the size of a normal head. It's like 50 centimeters or something in diameter. The brain is three pounds. It's a very confined little situation. How could there be no limits?

JONAH LEHRER: I wish there was a good answer. Nobody has any idea why it is he had this infinite capability for recall. What it does suggest, though, is that the brain has the capability to store an incredible amount of stuff.

ROBERT: How much stuff, though? How much can you jam into a human brain?

JAD: I don't—I don't think anyone knows. I mean, so let's just stop. Just call it quits. Go to the next—no, no, no. Forget that. In fact, let me take you to a competition which investigates that very question. We're gonna change locations from—where were we just now? Russia?

ROBERT: We were in Russia.

JAD: From Russia in the 1920s to—you ready for this? London, 2009. Here we are at the World Memory Championships.

ROBERT: The world what?

JAD: The World Memory Championships. Just go with me for a second.

ROBERT: Okay.

JAD: So we're in a hotel in central London, and the lobby is crowded with the world's best memorizers.

[ARCHIVE CLIP, interviewer: So what is your name?]

JAD: Got people here from, like, Oman.

[ARCHIVE CLIP, World Memory Championship 2009: Grandhi Rahdj, I'm Dr. Grandhi.]

JAD: Manchester.

[ARCHIVE CLIP, World Memory Championship 2009: Hello, I'm Emile Hawke.]

JAD: Netherlands.

[ARCHIVE CLIP, World Memory Championship 2009: Yeah. Rick D. Young.]

JAD: Even have a team of Chinese girls in the corner doing a cheer.

ROBERT: And what are we doing here?

JAD: Well, the people here are a little bit like the guy you were describing, Mr. S. They are walking experiments in brain stuffing. The difference is they're perfectly normal human beings.

[ARCHIVE CLIP, interviewer: Could start by introducing yourself?]

[ARCHIVE CLIP, Ben Pridmore: Okay.]

JAD: Like, take this guy.

[ARCHIVE CLIP, Ben Pridmore: I'm Ben Pridmore. I'm the reigning world memory champion. I'm 33 years old and I live in Nottingham.]

JAD: Ben can take a string of numbers that is 1,400 numbers long.

ROBERT: Random numbers?

JAD: Random numbers. And he can commit it to memory instantly. He can take a deck of cards and memorize it in 24 seconds.

ROBERT: Wow!

JAD: Yeah.

[ARCHIVE CLIP, World Memory Championship 2009: We've not actually reached, you know, any kind of upper limit of what it's possible to memorize, yet everybody's still consistently improving.]

JAD: So here's what we did. We—we found a guy.

RONNIE WHITE: Oh, I'm—my name's Ronnie White, and I'm the 2009 USA Memory Champion.

JAD: He's a Navy reservist from Dallas, Texas.

RONNIE WHITE: Matter of fact, I had to get permission from my unit to come here.

JAD: And we followed him around the competition.

INTERVIEWER: What's about to happen?

RONNIE WHITE: Well, the competition's about to start, you know? You know, it's day one. Should be a fun day.

JAD: Because we wanted to know, like, how do you do it? How do you take the limits of a normal brain and completely shatter them?

RONNIE WHITE: So I walked into the room that day wearing my Michael Phelps t-shirt. You know, it said "USA" on the front.

[ARCHIVE CLIP, World Memory Championship 2009: Okay, your one minute of mental preparation time starts now.]

RONNIE WHITE: The final minutes before you start an event, you're sitting in your chair and you're just collecting your thoughts. I put on my military glasses. I got some—they're like Drew Carey's glasses. And I put those on to remind me, hey, remain calm. You know, I wore those all throughout my tour in Afghanistan. And if you're going down a road and—and you're needing to be on the lookout for IEDs, but you're not calm, you're nervous and jittery, you could die. Then I'll put on some noise-canceling headsets. And then I just close my eyes, sit in my chair.

[ARCHIVE CLIP, World Memory Championship 2009: Ten seconds. Neurons on the ready.]

JAD: "Neurons on the ready," they say. "Go!" And at that moment, 60 people turn over papers. On these pieces of paper are numbers.

[ARCHIVE CLIP, World Memory Championship 2009: Six, seven, one.]

JAD: Nothing but numbers. Numbers, numbers, numbers, numbers, numbers forever.

ROBERT: And what are they doing?

JAD: Well, they have to memorize them.

ROBERT: So they're just—you're seeing all these people staring at pieces of paper?

JAD: Yeah. Absolute silence. Heads down, 60 heads down. Staring at numbers.

[ARCHIVE CLIP, World Memory Championship 2009: Six, seven, one.]

JAD: But here's the—here's the interesting thing: in their heads, they're not seeing numbers. Instead, those numbers are turning into ...

RONNIE WHITE: George Bush, Florence Nightingale, Randy Richardson, he's a friend. Barney Fife, a rash, Michael Jordan, Chuck Norris, Donnie Brasco, Bush—no, that was Boy George. Joe T, Martha Stewart, George Michael, Ben Franklin, Chuck Norris, Anne Frank, Indiana Jones, my friend Ronnie, King Tut. I have a person assigned to every number from 0 to 99. And then I have a verb assigned to every person from 0 to 99. And then I have a noun assigned to every digit. So you're just taking person, verbs and objects.

[ARCHIVE CLIP, World Memory Championship 2009: Stop memorizations. Please put the cards down.]

RONNIE WHITE: And you're putting them all together, and they really don't make sense.

[ARCHIVE CLIP, interviewer: What were some of the things? Give me an example of the ...]

[ARCHIVE CLIP, Ronnie White: The images I saw?]

[ARCHIVE CLIP, interviewer: Yeah.]

[ARCHIVE CLIP, Ronnie White: I saw Albert Einstein riding a roller coaster into a bunch of fog.]

[VOICE: Five-nine-three-seven-eight-seven.]

[ARCHIVE CLIP, Ronnie White: That was one of the images. I saw a Fat Albert cartoon character driving a car.]

[VOICE: Eight-one-nine-nine.]

[ARCHIVE CLIP, Ronnie White: I saw a Victoria's Secret model, which was one of my favorite pictures. [laughs] I saw a Victoria's Secret model shooting a gun.]

[VOICE: Hey, Ronnie!]

[ARCHIVE CLIP, Ronnie White: Stuff like that.]

ROBERT: [laughs] Stuff like that.

JAD: So there seems to be something about turning data into pictures that makes that data etch.

JONAH LEHRER: It becomes easier to hold on to.

ROBERT: Do you have any idea why?

JAD: Do I have any idea why?

ROBERT: Do you? I'm asking.

JAD: No. But Jonah might.

JONAH LEHRER: I don't know. I would just be purely speculating here, but the visual cortex has been hugely enhanced in human evolution. It's, you know, the rear half of our brain because we know that memories—you know, there is no memory center of the brain. It's—it's distributed in our sensory areas. It might make a little sense that given that we've got this huge chunk of visual cortex, that it's easier to store memory there.

ROBERT: Okay. So let me ask you, how did Ron's visual cortex do in the big contest?

JAD: Well, Ron—Ron didn't actually do so well.

ROBERT: He didn't?

JAD: Mm-mm. He was trying to memorize these 12 decks of cards, and he had constructed this whole, like, a stack of pictures, but he—he did them in the wrong order, and he screwed it up.

ROBERT: He lost?

JAD: He lost really badly, unfortunately.

RONNIE WHITE: I was shocked. I mean, I was just shocked. That—that knocked me out of any possible ...

ROBERT: You know who—by the way, who didn't lose? Remember Mr. S, the guy we started this conversation with?

JAD: Yeah, sure.

ROBERT: This is interesting. It turns out that Mr. S also had little pictures and little characters running around in his mind. But unlike Ron, he never asked for the pictures.

JONAH LEHRER: No, he couldn't. You know, even when he wanted not to do it, he couldn't help but do it.

JAD: Meaning what?

ELKHONON GOLDBERG: He was born that way. He had this tremendous memory without any effort and without any mnemonic techniques. This is the point.

JAD: You mean his mind made the pictures automatically?

JONAH LEHRER: Yeah.

ROBERT: Mr. S had a condition called synesthesia, where your senses get kind of tangled up.

JONAH LEHRER: So he heard voices in terms of colors ...

ELKHONON GOLDBERG: Right. Colors or voices.

JONAH LEHRER: ... textures ...

ELKHONON GOLDBERG: Smells of words.

JONAH LEHRER: And his numbers weren't just numbers. Sometimes he imagines walking through a crowded Moscow street, and the numbers are scattered along the way. And so he describes how I'm walking into the street, there's the number one.

ELKHONON GOLDBERG: This is a proud, well-built man.

JONAH LEHRER: Then I make a right turn onto the side street. There's the number ...

ELKHONON GOLDBERG: Two is a high-spirited woman.

JONAH LEHRER: Then I make a left turn. There's the number ...

ELKHONON GOLDBERG: Three, a gloomy person. Why? I don't know.

JONAH LEHRER: Nobody knows. Nobody knows exactly what accounts for the individual associations of synesthesia. They just exist. But they're this extra scaffold for Mr. S's memory to cling to.

JAD: Wow. So he's like Ron, except he's using all his senses to remember numbers.

JONAH LEHRER: Exactly.

JAD: So getting back to the plot. What did—what did he do with this talent?

JONAH LEHRER: He became a traveling circus freak, basically.

ELKHONON GOLDBERG: Yeah. Yeah, professional mnemonist. Yeah.

ROBERT: Mr. Memory.

ELKHONON GOLDBERG: He gave up journalism to perform for crowds.

ROBERT: Just imagine it went something—I don't know, like this.

[ARCHIVE CLIP, carnival: Ladies and gentlemen, please welcome the captain of cognition, the master of memory, the spectacular Shereshevsky! [applause]]

ROBERT: Imagine this is a big crowd. He walks on to the stage. He gives them an invitation. He asks them to ...

JONAH LEHRER: Shout random numbers.

[ARCHIVE CLIP, audience: 58! 25! 24! 157! 540! 45! 52! 203!]

ROBERT: Then after a little while, the crowd quiets down and Mr. S would close his eyes and step forward.

JONAH LEHRER: And he would remember them all.

[ARCHIVE CLIP, audience: [gasps] [applause]]

JAD: This was his job?

JONAH LEHRER: Yeah.

ROBERT: And it wasn't just numbers, by the way. He was thrown weird phrases, nonsense sounds, nouns, verbs. And sometimes he'd do four shows a day. And the more he did, the more obvious it became that this business of his, it had a downside. Here's where we're gonna finally reach, maybe, the limits question that we're really examining in this program. He would hear all these nonsense phrases being thrown at him and they would build up in his mind.

JONAH LEHRER: And it's important to note this was incredibly frustrating for Mr. S.

ROBERT: He had a constant stream of memories pouring into his brain. He couldn't get any of it out. And on top of that, as they piled up, the memories began to kind of mush together. One would trigger another and then another and then another.

JONAH LEHRER: It was this suffocating eating web of association.

ELKHONON GOLDBERG: The moment he encountered anything, everything even remotely related in his past to that something was immediately evoked in his memory.

ROBERT: For example, let's suppose a man in the audience stands up and he shouts out the word "dog." For a split second, Mr. S sees a dog, which suggests another dog and then another dog. And then ...

JONAH LEHRER: Every dog he ever saw.

ROBERT: And the man suggests not just that man, but the man beside him, other men, men that he knew ...

JONAH LEHRER: All the other competitions where a similar-looking man stood up and shouted something similar.

ELKHONON GOLDBERG: He was barraged. He was deluged. There was all kinds of memories totally unrelated. Everything layered, one layered on top of with the other.

ROBERT: That's horrible!

ELKHONON GOLDBERG: I agree.

ROBERT: Oh!

ELKHONON GOLDBERG: That would be a bloody nightmare.

JONAH LEHRER: The mind isn't just interested in storing information. It really wants to be able to get meaning out of that information, out of those memories. And that actually seems to be turned off, to be inhibited by remembering too much.

ROBERT: In other words, there really is a limit in our heads. It's a different kind of limit, really. Not the limitless ability to remember one number after another, but a precious balance in your head. If you remember too much, you will make no sense of the world.

JAD: It's weird. I've never actually thought of making sense of the world as being an—an act of negation.

ROBERT: Yeah.

JAD: Do you know what I mean?

ROBERT: It's very much that.

JAD: But it kind of makes sense because if you think about, like, living here in New York City. All the people you bump into. If you remembered every freakin' one, like, you wouldn't be able to have a relationship with your wife or your husband or your child, because they just be lost in this thick crowd in your head. It's like, "Get out!"

ROBERT: Out! Somehow, that's the balance. The act of forgetting is crucial to create preciousness.

JAD: Although I do wish I had a better memory.

ROBERT: What's your name again?

[LISTENER: Hey, this is Chris Callahan from Berkeley, California. And Radiolab is supported in part by the National Science Foundation, and by the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org.]

JAD: Hey, I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: This is Radiolab. And this next segment began with a simple question.

STEVE STROGATZ: Mm-hmm.

ROBERT: Seeing as our topic so far has been limits, and we've done body.

JAD: And we did the brain.

ROBERT: Now we're gonna go really big.

STEVE STROGATZ: Yeah.

JAD: Yeah. So we called up Steve Strogatz, mathematician at Cornell University, frequent guest on the show, and we asked him ...

ROBERT: Are there limits to human knowledge?

JAD: Yeah. And his answer sent us on a little adventure.

STEVE STROGATZ: The—yeah. Is there anything that's at the limits of our knowledge is a question that a lot of us scientists worry about. And—and certainly the 20th century taught us that there are many things that limit our knowledge. For instance, that the Heisenberg Uncertainty Principle in quantum physics showed us that you can't know the position and momentum of a subatomic particle at the same time. You just can't do it. It's not a matter of not having good enough instruments or not being clever enough. It's just a fundamental barrier that nature puts in your way. In logic, Gödel's Theorem tells us you can't prove certain things even though they're true. So we—there are all kinds of limits. But those seem a bit remote from everyday experience, and yet I think there are really important limits on our knowledge that we're all familiar with. What I'm thinking of here is our inability to think about big numbers, because with your fingers you've got 10—you know, normally. So we're good at 10, we're barely good at 100. And once you start getting into thousands, millions, billions and trillions, it gets hazier and hazier. When you hear now about the trillions of dollars in the deficit or whatever it is, the debt, you know, we don't—that means nothing. How are you supposed to think about that? Now when you ask, "Why can't we understand the common cold, but can put a person on the moon?" It has to do with large numbers.

JAD: Not just large numbers of numbers, says Steve, but large numbers of things interacting.

STEVE STROGATZ: That there are so many genes involved and so many biochemical reactions involved, our brains are limited, our memories are very limited. And so I worry a little bit that—that we might be approaching the end of our ability to have insight into certain kinds of questions.

ROBERT: What Steve means by the word 'insight' is not like you found the answer. It's like that ...

JAD: It's like a feeling.

ROBERT: Right.

JAD: You know, like that, "Oh, I get it!"

ROBERT: A feeling you get when you really understand the answer.

STEVE STROGATZ: Yeah, that satisfying feeling that I can see the reasoning.

JAD: I can actually feel it in my bones.

STEVE STROGATZ: That's—that's a very pleasurable feeling, but one that we may not always be able to enjoy.

HOD LIPSON: I mean, you can see the space. Good luck.

JAD: We weren't really quite sure how to feel about this. But then Steve said, "You know, don't take my word for it. Talk to these guys who work down the hall from me. You'll see."

HOD LIPSON: Yeah, we can—we can go right ahead.

JAD: Cool. Can you guys introduce yourself? Tell me who I'm talking to.

HOD LIPSON: Yeah. So my name is Hod Lipson.

MICHAEL SCHMIDT: My name is Michael Schmidt. I'm a PhD student.

HOD LIPSON: And I'm a roboticist.

JAD: And Hod and Mike have developed this thing, which does make you wonder if Steve's right. It's a computer.

HOD LIPSON: Yes.

JAD: Actually, many.

HOD LIPSON: A whole tower of computers that are all grinding away and performing calculations.

JAD: Actually, when you get down to it, it's just a piece of software. But they've named it ...

HOD LIPSON: The Eureka.

JAD: Because that's what it's designed to do, to have Eureka moments.

HOD LIPSON: Let—maybe a kind of simpler example ...

JAD: And the story of Eureka begins pretty simply, with a ...

HOD LIPSON: ... regular pendulum, okay?

JAD: With a pendulum.

HOD LIPSON: Just one of these things you see hanging off a grandfather clock.

JAD: Okay, I've got a regular pendulum swinging in my mind.

HOD LIPSON: Okay. Swinging left and right.

JAD: Now, says Hod, double it. Instead of a string connected to a ball, make it a string connected to a ball connected to another string connected to another ball.

MICHAEL SCHMIDT: Which is basically like a double pendulum. The cool thing about this is you just put it up, you lift it up and let it go.

JAD: And what you'll get, says Mike, is ...

MICHAEL SCHMIDT: Is chaos. This really crazy behavior.

JAD: Instead of nice and even, now you got random.

MICHAEL SCHMIDT: It's almost impossible to actually try to predict where this thing will move.

JAD: So what they did was they got a camera, connected it to Eureka, and basically just had Eureka watch this thing, you know, move about crazily. And then they asked the computer a really simple question: can you make some kind of sense out of this erratic behavior? Like, is there something in this system that always stays the same?

HOD LIPSON: Tell me what about these pendulums over time is not changing.

JAD: Because with everything, there's gotta be some kind of logic in there.

JAD: So you're looking for a law, basically. You're looking for the law of the double pendulum.

HOD LIPSON: Yes. That's the idea.

JAD: So Eureka is there watching this pendulum.

MICHAEL SCHMIDT: It was about 3:00 am in the lab.

JAD: And it's basically spitting out all of these different guesses.

HOD LIPSON: Formulating hypotheses.

MICHAEL SCHMIDT: It's getting closer. Closer.

JAD: And then onto the screen pops this simple formula: F=ma.

JAD: What is F=ma? Is that actually the law that ...

HOD LIPSON: F=ma is Newton's law of motion.

ROBERT: The Isaac Newton.

JAD: That's Sir Isaac to you.

HOD LIPSON: It's a basic law of physics.

JAD: And one of the greatest discoveries in the history of human thinking.

HOD LIPSON: Took it about a day, 24 hours. But—but the interesting thing is that it came up with this thing without knowing anything about physics. Nothing. That's why we kind of—we think that this algorithm might be able to find new laws that we don't know about yet.

ROBERT: In fact, once word got out about Eureka ...

JAD: That's when the emails started.

HOD LIPSON: A couple of emails a day.

JAD: From scientists all over the place who were like, "Hey."

ROBERT: "Do you mind if we borrow your robot?"

JAD: For what kinds of stuff?

HOD LIPSON: Anything you can think of from trying to predict behaviors of cows in a herd, to particle physics, to the stock market.

ROBERT: And that's—this is when we get to Steve's point about the limits of insight.

JAD: That's when they met this guy.

GUROL SUEL: My name is Gurol Suel.

JAD: Gurol is a biologist.

GUROL SUEL: At the University of Texas Southwestern Medical Center.

ROBERT: He got in touch with Hod.

HOD LIPSON: And he said, "I have this amazing data, which is single cell dynamics."

JAD: Meaning he's got this tiny little thing.

GUROL SUEL: It's a simple bacteria.

JAD: Really basic.

ROBERT: And he's been collecting this information on how it works.

JAD: On its inside.

GUROL SUEL: How things go up and down. Certain nutrients increase, certain nutrients decrease over time, just like a pendulum.

JAD: But the thing is, in a cell, it's like thousands of pendulums.

HOD LIPSON: There's so many parts.

ROBERT: Genes turning on and off.

GUROL SUEL: Thousands and thousands, tens of thousands.

JAD: Proteins turning on other genes and nutrients going up and down.

ROBERT: It's this crazy quilt of complicated feedback.

JAD: And he wanted to know: inside of this cell, how are all of these things related? I mean, we can measure it all. We can see things going up and down and all that.

ROBERT: But what are the rules?

JAD: What are the rules. And this, he says, is the problem for biology.

GUROL SUEL: Biology is one of the least well-understood systems compared to, let's say, chemistry and physics.

JAD: They're still lacking the basics.

GUROL SUEL: So we said, "Look, Mr. Robot, can you tell us what do you think are sort of the important principles governing this organism, and maybe detect things that were hidden from us?

HOD LIPSON: So he sent us the data and we analyzed it, and ...

ROBERT: Well, okay. Yeah, so what happens?

HOD LIPSON: Suddenly equations started popping out.

GUROL SUEL: Almost immediately. The robot came back to us and said, "Okay, here's a set of two equations that describe your data."

JAD: Do you remember by any chance, what the—what the actual equation was? Not—not that we'd understand it, but just sort of to hear it said out loud?

GUROL SUEL: Yeah. No, I don't. I don't have my Rain Man skills developed to that degree yet.

JAD: The important thing is that the equation was telling him things like when this protein goes up, this other thing always goes down. And when that thing goes down, this gene turns on and does a loop de loop. And when he went to his cell to check all this out, the equation was right.

HOD LIPSON: These equations matched the data. And in fact, they explain new data.

JAD: These equations could even predict what the cell was about to do. But hold the champagne. There's just one little problem here. The formulas check out, but ...

HOD LIPSON: We don't know what they mean.

JAD: You don't know what they mean?

HOD LIPSON: Right.

JAD: Meaning they don't know why these equations work.

ROBERT: Right. Why when this goes up, does that go down? Why when that goes up, does this go sideways? Why?

GUROL SUEL: I had to first look at this and try to make sense of it. We said, like, "Oh, okay. I think we understand." Then we're like, "Oh, maybe we don't." We think that we're close to understanding it.

HOD LIPSON: But, you know, now we're in this bizarre situation. We can't even publish it right now because we can't just publish a equation without explaining it.

JAD: So in the end, they're in this awkward position where they've got the answer, but they don't have the insight.

HOD LIPSON: And I think it's a preview of what's to come in science.

JAD: The more we turn to computers with these big questions, the more they'll give us answers that we just don't understand.

HOD LIPSON: We'll be faced with this challenge of having to find ways to get a computer to explain what it found.

STEVE STROGATZ: But that will leave us, if this really happens, in some weird position as bystanders, where we're sort of listening to the oracle, but not really understanding the answer. Is there gonna be a time when we—we can't cut it anymore? We've had this—this window in human history when we could not just know things but actually understand them. That is, you could know why they were true. Not just know, but to know why. And that's a beautiful moment in human history. But I feel like it may only be a moment.

GUROL SUEL: Well, I don't really see it quite that—that sort of sad and dramatic, because at the end there will be simple principles to describe even the most complicated of processes.

JAD: So you have a bias that prevents you from feeling the kind of despair that Steve feels and that we were hoping you would feel.

ROBERT: [laughs]

GUROL SUEL: Oh, well. I have a positive outlook.

JAD: [laughs]

ROBERT: Well, I'm just wondering about the 'we.' "Look what 'we' have discovered," you'll say when you're an old man with your robot sitting there in a dress next to you. And the robot will be holding your hand, but that will be a cold hand. And Jad and I will be thinking, "I don't know, who's the 'we' here? Is it like the ..."

GUROL SUEL: Well, I would say 'we' is sort of knowledge. I'm just thirsty for understanding and thirsty for knowledge. Me and the cold hand holding my hand, we've accumulated and contributed to the overall understanding of something that we thought maybe 50 years ago wasn't possible, and that would be something that would make me happy.

[STEVE STROGATZ: Hi, this is Steve Strogatz. Radiolab is produced by Jad Abumrad. Our staff includes Ellen Horne, Michael Raphael, Soren Wheeler, Lulu Miller and Pat Walters, with help from Adi Narayan, Tim Howard and Sharon Shattuck. Special thanks to Steven Auerbach. All right. Thank you. Bye-bye.]

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