The 100,000-student classroom

In the fall of 2011 Peter Norvig taught a class with Sebastian Thrun on artificial intelligence at Stanford attended by 175 students in situ -- and over 100,000 via an interactive webcast. He shares what he learned about teaching to a global classroom.

Everyone is both a learner

and a teacher.

This is me being inspired

by my first tutor,

my mom,

and this is me teaching

Introduction to Artificial Intelligence

to 200 students

at Stanford University.

Now the students and I

enjoyed the class,

but it occurred to me

that while the subject matter

of the class is advanced

and modern,

the teaching technology isn't.

In fact, I use basically

the same technology as

this 14th-century classroom.

Note the textbook,

the sage on the stage,

and the sleeping guy

in the back. (Laughter)

Just like today.

So my co-teacher,

Sebastian Thrun, and I thought,

there must be a better way.

We challenged ourselves

to create an online class

that would be equal or better

in quality to our Stanford class,

but to bring it to anyone

in the world for free.

We announced the class on July 29th,

and within two weeks, 50,000 people

had signed up for it.

And that grew to 160,000 students

from 209 countries.

We were thrilled to have

that kind of audience,

and just a bit terrified that we

hadn't finished preparing the class yet. (Laughter)

So we got to work.

We studied what others had done,

what we could copy and what we could change.

Benjamin Bloom had showed

that one-on-one tutoring works best,

so that's what we tried to emulate,

like with me and my mom,

even though we knew

it would be one-on-thousands.

Here, an overhead video camera

is recording me as I'm talking

and drawing on a piece of paper.

A student said, "This class felt

like sitting in a bar

with a really smart friend

who's explaining something

you haven't grasped, but are about to."

And that's exactly what we were aiming for.

Now, from Khan Academy, we saw

that short 10-minute videos

worked much better than trying

to record an hour-long lecture

and put it on the small-format screen.

We decided to go even shorter

and more interactive.

Our typical video is two minutes,

sometimes shorter, never more

than six, and then we pause for

a quiz question, to make it

feel like one-on-one tutoring.

Here, I'm explaining how a computer uses

the grammar of English

to parse sentences, and here,

there's a pause and the student

has to reflect, understand what's going on

and check the right boxes

before they can continue.

Students learn best when

they're actively practicing.

We wanted to engage them, to have them grapple

with ambiguity and guide them to synthesize

the key ideas themselves.

We mostly avoid questions

like, "Here's a formula, now

tell me the value of Y

when X is equal to two."

We preferred open-ended questions.

One student wrote, "Now I'm seeing

Bayes networks and examples of

game theory everywhere I look."

And I like that kind of response.

That's just what we were going for.

We didn't want students to memorize the formulas;

we wanted to change the way

they looked at the world.

And we succeeded.

Or, I should say, the students succeeded.

And it's a little bit ironic

that we set about to disrupt traditional education,

and in doing so, we ended up

making our online class

much more like a traditional college class

than other online classes.

Most online classes, the videos are always available.

You can watch them any time you want.

But if you can do it any time,

that means you can do it tomorrow,

and if you can do it tomorrow,

well, you may not ever

get around to it. (Laughter)

So we brought back the innovation

of having due dates. (Laughter)

You could watch the videos

any time you wanted during the week,

but at the end of the week,

you had to get the homework done.

This motivated the students to keep going, and it also

meant that everybody was working

on the same thing at the same time,

so if you went into a discussion forum,

you could get an answer from a peer within minutes.

Now, I'll show you some of the forums, most of which

were self-organized by the students themselves.

From Daphne Koller and Andrew Ng, we learned

the concept of "flipping" the classroom.

Students watched the videos

on their own, and then they

come together to discuss them.

From Eric Mazur, I learned about peer instruction,

that peers can be the best teachers,

because they're the ones

that remember what it's like to not understand.

Sebastian and I have forgotten some of that.

Of course, we couldn't have

a classroom discussion with

tens of thousands of students,

so we encouraged and nurtured these online forums.

And finally, from Teach For America,

I learned that a class is not

primarily about information.

More important is motivation and determination.

It was crucial that the students see

that we're working hard for them and

they're all supporting each other.

Now, the class ran 10 weeks,

and in the end, about half of the 160,000 students watched

at least one video each week,

and over 20,000 finished all the homework,

putting in 50 to 100 hours.

They got this statement of accomplishment.

So what have we learned?

Well, we tried some old ideas

and some new and put them together,

but there are more ideas to try.

Sebastian's teaching another class now.

I'll do one in the fall.

Stanford Coursera, Udacity, MITx

and others have more classes coming.

It's a really exciting time.

But to me, the most exciting

part of it is the data that we're gathering.

We're gathering thousands

of interactions per student per class,

billions of interactions altogether,

and now we can start analyzing that,

and when we learn from that,

do experimentations,

that's when the real revolution will come.

And you'll be able to see the results from

a new generation of amazing students.

(Applause)