So, I'm from Guatemala. This is a public service announcement, that is where Guatemala is. (Laughter) Also, that is not
where they keep the prisoners. That is called Guantanamo. (Laughter) Not the same place. So Guatemala's right below Mexico. And for the Americans in the audience, and let this sink in,
because it really applies in most ways, for the Americans in the audience, you can think of it as Mexico's Mexico. (Laughter) Just like the US doesn't want
illegal immigration from Mexico, Mexico doesn't want
illegal immigration from Guatemala. It's a smaller country. It's a poor country. And well, what can I tell you, it has much better Mexican food. (Laughter) Guatemala is a very poor country. And a lot of people talk about education as something that brings equality
to different social classes. But I always saw it as the opposite,
as something that brings inequality. Because what happens in practice is that people who have a lot of money
can buy themselves a really good education and therefore continue
having a lot of money. Whereas people who don't have
very much money barely learn how to read and write and therefore never make a lot of money. And this is especially true
in poor countries. Now, I was fortunate that I received
a rich person's education even though I didn't grow up rich. And it’s because I’m an only child. And my mother, who was a single mother, spent all of her resources
on my education. And this allowed me to come
to college to the US and eventually get a PhD
in computer science. Now because of all of this about 10 years ago, I decided I wanted to do something that would give equal access
to education to everyone. Oh, by the way, this is what I want
to talk to you about today, giving equal access
to education to everyone. At the time, I was a professor
of computer science at Carnegie Mellon University, and I decided to work on this
with my PhD student, Severin. The way my brain works, all of education is just
too general of a problem. So I decided, let's start
by teaching one thing. And then I started thinking,
OK, well, what should we teach first? Should we teach math? I mean, we both love math. Me and my cofounder, we both love math. And, you know, we didn't
decide to do math. Then we started thinking, well, maybe
we should teach computer science. But eventually, and this is maybe
surprising to people in North America, eventually, we decided
that the best subject to start with was teaching foreign languages. And let me tell you why. There's a number of reasons. One of them is that there's
a huge audience for it. There’s about two billion people
in the world learning a foreign language, both in school and outside of schools. Most of these people, by the way,
are learning English. About 80 percent of them
are learning English. In this weird map right here, all the countries in green are countries in which people
are predominantly learning English. And the reason for that is because English can truly
transform your life. In most countries in the world, knowledge of English can significantly
increase your income potential. So this is another reason why we decided
to start with foreign languages. And it's because you can directly
make more money if you learn another language,
in particular English. And see, this is pretty different
than many other subjects. For example, take math. In the case of math, just knowledge of math does not
increase your income potential because usually you have to learn math
to then learn physics to then become a civil engineer,
that's how you make more money. Whereas with languages,
if you are a waiter and you learn English, now you can be a waiter at a hotel
and make more money. So we decided, well, let's get started
by teaching languages. Now, we also convinced ourselves that the only way
to really reach a lot of people was by using a mobile phone,
or a smartphone in particular. See, building schools all over the world
is simply too expensive. On the other hand, most of the world's population
already has access to a smartphone, and the trend is that that fraction
is only going to increase. So we decided at the time that we would make a way to learn
foreign languages on a mobile phone that was accessible to everyone. And then we called it Duolingo. Thank you. (Applause) Now in order to truly be accessible
to everyone, rich and poor, Duolingo uses a freemium model
to support itself. What that means is that you can learn
as much as you want without ever having to pay. But if you don't pay, you may have to see an ad
at the end of a lesson. Now, if you don't like ads, you can also pay to subscribe
to turn off the ads. And it turns out that the vast majority
of the revenue for Duolingo comes from people who pay
to subscribe to turn off the ads. Now, who are these people who pay
to subscribe to turn off the ads? Well, they're usually well-off people
in rich countries like the US and Canada. Who are the people
who don't pay to subscribe? They usually come from poorer countries
like Brazil or Vietnam or Guatemala. So what I like about this model is that it is a small form
of wealth redistribution because we're basically
getting the rich people to pay for the education of everyone. So I like that. (Applause) So with smartphones,
we can reach a lot of people and we can even get the rich people
to pay for the whole thing, which is great. However, if you're trying to deliver
education with a smartphone, you run into a humongous problem. And it is that smartphones come equipped with some of the most addictive drugs
that humanity has ever engineered. TikTok, Instagram, mobile games. See, delivering education
over a smartphone is like hoping that people
will eat their broccoli, but right next to it, you put
the most delicious dessert ever made. (Laughter) If you really want to deliver
education to everyone, not only do you have
to make it accessible, but also you have to make it
so that people want to actually learn. And with Duolingo,
we've been able to do this. And at the highest level,
the way we've done this is by making the broccoli
taste like dessert. I'll say it another way. What we've done is that we've used
the same psychological techniques that apps like Instagram,
TikTok or mobile games use to keep people engaged, but in this case, we use them
to keep people engaged but with education. Let me give you some examples
of these techniques. One of the most powerful ones
is the notion of a streak. What a streak is, is it’s just a counter that measures the number of days that you've used
the product consecutively. You just take that number, you put it very prominently
in your product and then people come back every day. And the reason people come back
every day is because, well, if they don't come back,
that number resets to zero and people don't want
to lose their streak. It works. Now, on the one side, streaks have been criticized
for, for example, getting teens addicted to Snapchat. But in the case of an educational app, streaks get people to come back
to study every day. Now, to give you an idea
of the power of streaks, in the case of Duolingo, we have over three million
daily active users that have a streak longer than 365. (Applause) That means they haven't missed a day
in the last year or longer. Now, fun fact about streaks. What country do you think
has the longest average streaks for an educational app? It's Japan. Of course. Shortest-ever streaks? Latin America, baby. (Laughter) But we're fun, hey, we're fun. (Laughter) Another important mechanism to get people
to come back to your product are notifications. On the one side, notifications
can be really spammy and annoying, but in the case of an educational product, people actually want
to be reminded to learn. In the case of Duolingo, we have
a very sophisticated AI system that basically chooses
when to send the notification and also what to say in each notification to maximize the probability
that people come back. Now, interestingly, even after all this sophistication, it turns out that the algorithm
for choosing what time to send you a notification
is pretty simple. Do you know what is the best time
to send people a notification? I'll tell you. It's 24 hours after
they used the product last. There's an easy explanation. If you were free yesterday at 3pm, you’re probably free today
at 3pm as well. So this is what a very sophisticated
millions of dollars of AI found. (Laughter) It's funny. Now with notifications
you shouldn't be spamming. And we're not spamming, with Duolingo, we actually stop sending notifications
after seven days of inactivity. So if you don't use Duolingo
for seven days, we stop sending you notifications. Now, at some point it occurred to us, if we're stopping
to send people notifications, we should let them know. So we started sending
this notification to people saying, "Hey, these reminders
don't seem to be working. We'll stop sending them for now." You know what people do
when they get this notification? They come back. (Laughter) Passive aggressive. (Laughter) Works for my mother, works for Duolingo. (Laughter and applause) These passive aggressive notifications are really good at getting
people to come back back because they feel like our green
owl mascot has given up on them, so they come back. And speaking of our
green owl mascot, by the way, because all our notifications come
from our green owl mascot and well, he's passive aggressive
and also pretty pushy, this has given rise to a lot
of memes on the internet that make fun of the great lengths
that he will go through to get you back to learn a language. Here's one of my favorite ones. This is it's a meme,
it’s one of my favorite ones. (Laughter) Basically looks like you forgot
your Spanish lessons. And then there's an intruder alert, presumably the owl broke into your house
to get you to learn language. Now, Duolingo has entered the zeitgeist. And there's thousands of memes,
there's SNL skits about it. And it's because we've managed
to get people to want to learn a language by using the same techniques that mobile games and social media use
to get people engaged. And this is a really important point, let me say this. I don't actually believe that there's
a way to make an educational app be as engaging as something like TikTok
or Instagram or mobile games. But the good news is that -- And by the way, the reason
I don't believe that is because ultimately you have
to teach people something. And it's hard to compete with,
like, cats and celebrities. But the good news is
that I don't think you have to. See, here's the thing. When you're learning something,
you get meaning out of it. Whereas when you're scrolling
for two hours on Instagram, a lot of times afterwards, you feel
like you just wasted your time. So I think it's actually OK
if your educational product is only 80 or 90 percent as engaging
as something like TikTok, because the other 10 or 20 percent will be provided
by people's internal motivation, though of course, not much more than that. This is really a key point. If we want to get people
to do something meaningful, you can use the same techniques
that apps like social media use to get people to do it. And even if you're not as engaging
as those apps are, you can still get hundreds of millions
of people to use your product. In the case of Duolingo, for example, there are more people learning languages
on Duolingo in the United States than there are people learning languages
across all US high schools combined. (Applause) And this is true
in most countries in the world. My hope is that -- I know
we can do this, but, you know, my hope is that as humanity, we can do what Duolingo has done
for learning languages but for all other subjects. Where we can get people
to learn math with mobile phones, like millions of people to learn
math with mobile phones or physics or whatever. I hope for a future in which
screen time is not a bad thing, in which we can deliver high-quality
education to everyone, rich or poor, using a mobile phone. But the single most important thing
that I can end this talk with, is a reminder to please,
pretty please, I beg you, do your language lessons today. Thank you very much. (Laughter) Thank you. (Applause) Helen Walters: Luis, thank you so much. I wonder if you can just say
a little bit more about that last point, how do you think you can apply
this type of thinking to other subjects? So you mentioned math,
and things like that. How do you do that? Luis von Ahn: I think in particular, subjects that are learned
through repetition and it turns out most things
that are kind of really meaningful are learned through
thousands of repetitions. You learn to read through repetition, you learn elementary school math
through repetition. Most things that you can learn
through repetition, you can actually gamify
and turn into something like Duolingo, where people just
do it a lot and do it fun. It's a little harder for things
like explanations. That probably is going to require
some really good videos. Sal Khan is doing a really
good job with that. But for things that require
a lot of repetition, I think we can use the same methods. (Applause)
