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Why a Computer Is Often the Best Teacher, According to Duolingo's Luis Von Ahn (Full Video)

"I think all of education should be like this."

Asa Mathat

Luis von Ahn is a computer scientist. He didn’t know much about education before founding his current startup, Duolingo. To get up to speed, he read a bunch of books about various teaching methods that completely disagreed with one another. It was about as conclusive as reading diet books, he says.

But by taking a computer science approach, von Ahn thinks he can figure out how to teach, he said at our Code/Mobile conference. It’s a matter of testing different methods and evaluating what works to get people to actually learn.

So for instance, Duolingo — which today offers about a dozen languages, and soon wants to try to teach literacy as well — can try introducing plurals earlier and later in its curriculum. It can observe which students pick up the new concept and when, and rewrite the lessons around that timing. With 15 million active users, it can run experiments like that every day.

“That’s something the offline education system would have taken 15 years to figure out, because the iteration speed is so slow,” von Ahn said. “Literally, you have to wait a full year for iteration, whereas for us it takes one day.”

At Duolingo, it’s not just curriculum planning that’s designed by algorithm. The company is also using tricks from games like Candy Crush that encourage addictive behaviors, like giving students a simple question to build back their confidence after they miss a harder one. Duolingo is now primarily used from mobile phones — 85 percent of usage is mobile — and people say they “play” Duolingo because it’s fun and they don’t feel like they’re wasting their time.

Duolingo does seem to be working, according to a study by outside researchers of the company’s Spanish learners that showed they are picking up a semester’s worth of college Spanish in about 34 hours. “Already we’re comparable to a classroom,” von Ahn said. “I don’t think we’re as good as a one-on-one tutor, but I think we can get there.”

Would Duolingo’s algorithmic optimization concept work for subjects other than language learning? “I think all of education should be like this,” von Ahn said. “I think we can do a better job than the current educational system. The way teachers teach is going to change. It should be done in a totally individualized way, and making it fun — by looking at data for millions of people and tweaking to be as addictive as possible. Like being addicted to a game, now you’re addicted to learning something.”

It sounds a bit creepy, but at least von Ahn isn’t applying his computer science and psychological research talents to getting us to click on more ads.

Here’s the full video of the session:

This article originally appeared on

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