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by Sally Ann Flecker
The machines—those great, solemn machines—moving in persistent rhythm through the rituals of their work. That's what the boy breathed in, whether he knew it then or not. He spent most of his childhood playing here—a candy factory in Guatemala owned by his mother's family. Even the apparatus with the least exciting job—the one that wrapped the cough drops, for instance—was a marvel to him. Sometimes he would look at something—a gummy bear or a marshmallow—and try to work backwards to the system that could produce such a thing. The process was always very clever, beyond any mechanism he could imagine.
You might think the boy who notices such things will grow up to be an engineer or an inventor. And he does, in a way. But what is important here is how he learns to twist and turn his ways of thinking into something every bit as clever as those enigmatic machines. Because that's who the boy becomes— someone who dreams up things beyond what everyone else can imagine. Great minds may think alike. But the greatest minds think in completely unexpected ways. They're the ones who take you where you had no idea you wanted to go. When you get there, you say, of course, how could it have been any other way? And that is exactly what this boy will do.
When Luis von Ahn '00 gives a talk, he'll show on the projector screen the kind of squiggly, hard-to-read word you often have to type to gain access to a site on the Internet. "How many of you have gone on a website where you've been asked to read a distorted sequence of characters like this?" he'll ask his audience. A few hands will clap. Next he asks, "How many of you found it really, really annoying?" There'll be some laughter. Then he'll deliver his punch line: "Okay. Outstanding. So. I invented that." He's got the timing of a standup comedian delivering a monologue, perhaps not what the audience is expecting when they come to hear one of the leading computer scientists of our day.
At thirty-two, he's still ever-so-slightly baby-faced. His Latino inflection is easy on the ear. And oh, by the way, he's the guy who is changing the way that millions of people interact with the Internet.
The truth is he's very down-to-earth for a person who solved one of the biggest problems of the Internet in 2000 as a first-semester graduate student at Carnegie Mellon University. That was when Yahoo called on his Ph.D. adviser, eminent computer scientist Manuel Blum, for help.
The Internet service was in a quandary. Spammers were using "bots," automated programs, to sign up for thousands of Yahoo's free e-mail accounts every minute. Once the accounts were set up, they were used to send hundreds of millions of unwanted email messages. Yahoo asked Blum how that could be stopped.
Blum and von Ahn put their heads together and came up with the idea of creating a test that would distinguish humans from computers. It had to be a test most humans could pass and computers couldn't. And that was a little tricky. It meant a computer had to administer and grade a test it could not perform itself.
They started brainstorming. Most of the ideas were "crappy," von Ahn says, characteristically blunt about his own work. One idea did have merit. Knowing that computers can't identify images, Blum and von Ahn designed a test in which humans were shown several related pictures and asked to identify a word that described them all. But it turned out people could come up with too many unexpected answers. A horse, a guinea pig, and a monkey could be animals, or maybe pets.
Finally, they landed on distorted characters. People are pretty good at discerning characters, even when they're twisted and stretched like the Sunday comics on Silly Putty. Most computers are lousy at it. And so Blum and von Ahn created those funky characters that are familiar now to anyone who's signed up for a listserv or booked an event ticket in the past ten years. They named the program CAPTCHA—Completely Automated Public Turing Test to Tell Computers and Humans Apart. It was an elegant solution to Yahoo's problem—and a landmark moment in von Ahn's career. You can go a lifetime without having an idea that pure and revolutionary. And von Ahn was just getting started. He started thinking bigger.
The boy in the candy factory is also the kid who didn't get what he wanted. Which turns out to be his great good fortune.
What the boy wants, when he is eight, is a Nintendo. What his mother comes home with is a Commodore 64—an early computer that you plug into your television. "I hear you can play games on these," she tells him. "This is the one you get."
And you can play games on it, but first, you have to learn how to use a computer. In this case, that means learning the BASIC programming language. Keep in mind that he is at an age when most kids are learning how to multiply two-digit numbers, read chapter books, and follow the illustrated directions for a Lego set. But the boy takes on the challenge. He reads the manual and gets started. Then he goes out and buys some magazines to learn more. When he knows enough about the computer to play games on it, he talks his mother into buying some. After about five games, she decides they're too expensive to keep buying. That's it, she tells him. We're done.
But he is not ready to be done. He figures out how to get rid of the copy protections so he can exchange games with the other Commodore 64 enthusiasts that he's met in town. By now he's all of ten years old. It's clear that he's got a talent. His mother buys him an IBM PS-2, the kind of computer that is being used in offices and at universities. It's a serious computer, and he is serious about it.
But there is no World Wide Web, no discussion forums to consult. There is a tiny bookstore in Guatemala City. But even when he can find someone to drive him there, it almost never has the book he is looking for. So most of what he learns is because that's what's at the bookstore. Once again, he's not getting what he asked for. He's getting the answers to questions he couldn't have known to raise.
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