It's an important question why? Well, the first answer is probably obvious.

There are new media all the time. Just in the last week

we've had Samsung announce a watch,

other manufacturers coming in saying we have watches too.

We have autonomous cars that will come out by 2020,

first announcement we'll be driving. All these different technologies are

appearing,

so sure that should lead to an increase in media use. There's a second important

trend,

which is increasingly media are not just producing

one stream of information. Their producing multiple streams.

We know that computers have many windows, we know that while we're using our

phone we can surf the web.

Tablets allow for more and more functionality. Almost

every device now including a watch can give us

many pieces of information at once. So there's one engine of change which is a

technological change.

Very important, but it's not the only one. There's a second change,

which is a change of culture in media use. So let me give you some examples.

One of the lovely things to do France,

California, throughout the world is to go to the beach.

You smell the ocean breeze, you

hear the lapping of the waves,you feel the sand on your feet. How could that

not but be enhanced

by an IiPad. Or another example

you go to a wonderful restaurant. Every known culture

organizes enormous rituals around food.

Food is the time where we rarely eat alone, we eat in

groups. We engage, we talk with each other,

we see each other in a highly intimate setting.

And of course obviously we should have a phone in there is well.

With the third example, one of the great joys

every culture knows is children at play.

Their laughter, their engagement,

their excitement, the raw physicality of children

playing together. How could we miss out on that?

Well in fact there's been a fundamental change.

Media had introduce themselves into these activities,

which seemed extremely intimate and powerful.

That has very important effects. On top of that that there is a

third dynamic driving the growth immediate use and not just

single media use and that's the process

a partial media displacement. Probably one of the most important and least

known theories the field of communication. It's very simple one at

first,

just what happens when the new information product or service appears.

Well I think you can all guess the first thing that would happen it would steal

time from other information activities.

So movies stole time from books,

radio stole time for movies, television still time for radio

the internet steals time from television, etc. A very obvious process.

If that was the whole story would be a very exciting story

but what makes media so powerful, so exciting, and so seductive

is it not only did they steal time from information activities,

they also start stealing time from non information activities.

So ever since the middle stages the Industrial Revolution,

we've seen year-over-year growth of media use

with blips every time a new medium appears.

<edia steals time from non-media. However, a

third phenomena started to happen, which is media started also stealing time

from face to face communication.

So all of a sudden now not only

are we taking time away for more non

human to human relationships, media is now moving in

and taking time from our human relationships. You might think there's

any answer to that. Here's my

day planner. And sure, I'm gonna schedule more and more media time

and my day planner may get tighter and tighter and tighter

but there's gonna come a moment when I can no longer

have media steal time and at that moment, something big has to happen.

That happened around the early-1990s

for teenagers and has increasingly hit

other age group. No more time to steal.

At that moment in history, there was an inflection point

and society could have gone one of two directions.

One direction it could have gone was to say that's it no more trying to steal fair

enough.

If a new medium comes in, it's gonna take time from other media,

end of story, it loses.

That could have happened but it didn't happen.

Instead would happen was the use

of media in parallel with a other activities.

We double book media. Just as we were too busy to fit in, what we do we schedule

two meetings at the same time in hope one of them will work out.

Or three meetings or four. We're doing the same thing with media.

We schedule a media,we schedule as many as we can.

We cram it in and hope it'll work out. We'll see in a few minutes

it doesn't work out so well. In fact what effectively is happening,

we're seeing the horizontalization of media use.

Our day planners, instead of stealing vertically, are now stealing

horizontally.

This is a phenomena called multitasking

and multitasking is ubiquitous. We see in all these different domains

and we can ask the question how ubiquitous is it?

Well, the average the inferred student uses three media at the same time,

which means for faculty we know that when they're writing a paper,

they're listening to music and watching the cat play the piano.

Or some other activity because they've gotta use three media at a time.

And the top 25 percent of Stanford students are using four or more media

at one time when ever their using media. And it's not just writing papers.

When they're consuming entertainment, when they're at the movies,

a time that used to be a time to be transported into another world,

to be totally immersed and absorbed. They are not immersed and absorbed

because they're twittering. They're putting themselves back.

They won't immerse into media,

they're are enormous consequences. There also on top of these dynamics

there are corporate policies that dictate multitasking.

You increasingly see companies say email should be answered next minutes,

but what does that mean? That means you're checking your email at least

every

X minutes. Were told to keep our chat windows open

so that other team members can reach us at any time

and distract us from what we're doing. And of course

our cell phone is not just something we can use for personal use,

it's become a work phone, which means work, time with friends,

time with family have all become blurred. Media stealing time

from other media. Now what the cognitive consequences that?

Well we can ask the question does at the moment multitasking

impede performance? And if you talk with Stanford students, they will say they do

have the superpower,

which is using many media at one time. However,

sadly, it's a lie. In fact, you're more likely to be able to fly or be invisible

then use many media at one time. It turns out the brain just can't do it,

at least in respect media, and in fact performances impeded.

Everything from the little runner at the bottom of CNN or

ESPN or the others channels. Turns out

you actually learn less from both with the person speaking is saying

and the little runner at the bottom. You just can't do it.

But in some sense it couldn't be any other way because the brain is not built

that way.

We only have about three bits for short for working memory

and three but is not whole heck of a lot to do stuff.

What we want to talk about is actually two more pernicious effect,

the least appreciated effect, which is the effect of chronic multitask.

So here, I lived for the past seven years in a freshman dorm a resident fellow

in Otero, if any of you lived in Otero, I'd love to hear from you,

and at Otero I would see the kids multitasking all the time.

And I say, well, what's going on here? Don't you think there's going to be a problem. THey

would tell me things like this:

When it really matters I don't multitask.

Or multitasking doesn't bother me because I do it so often.

Or a favorite of every professor who gets older as freshman stay 18,

young brains were able to multitask, Prof. Nass,

you dot dot dot can fill in whatever blank you wish.

Well, I was jealous of those students and wanted to know whether in fact they

could really do something I couldn't do. I wanted to know their secret

to success. So we actually did a number of tests with them, which will talk about

no breakout session, but i just give you one example.

This is a task you'd think the average seven-year-old would be able to navigate

without difficulty and certainly

a Stanford student. But I'll ask you to do a real quickly.

I'm gonna show you a group of rectangles twice.

I want you to ignore the blue rectangles. All I want you to do is pay attention

to the red rectangles.

And make it easy for you, there'll only be two red rectangles.

And to make it even easier they're not going to even move their location.

All that's gonna happen is between the first and second picture

one of the rectangles is gonna rotate and I want to know whether

red rectangle rotated or not. Does that make sense? Couldn't imagine a simpler task, only two

red ones, just pay attention,

ignore the blue. It's very easy, okay. So here's what it would look like>

They would see this for 200 milliseconds then for 100 milliseconds they'd see

picture 1.

Then there would be a clearing of the retina and then

you would see the second picture. So how many of you thought a red rectangle rotated?

How many thought a red rectangle didn't rotate?

Well turns out a red rectangle did rotate and it turns out is what happens with

the students.

the students who do not multitask were unfazed by the number of blue rectangles

it was 0, 2, 4, 6 made no difference whatsoever.

But the high multitaskers got lost

in the world the blue it was. There were so many distractions and so few things to really

worth paying attention to,

how could they not but be seduced.

So that is enormous implications and we'll talk about some the other effects of

that.

But, um, just real briefly multitaskers too many other problems.

They can pay attention even when they want to. They

are actually very poor at managing working memory and they find it very difficult to

focus on writing

and they don't even multitask very well. Turns out people multitask all the time a

worse at it than people who never do it.

That made me wonder what the heck is going on? What is their problem?

Well the problem lies in the brain

this is a fMRI, functional magnetic resonance imaging scan.

of high and low multitaskers, doing

the task of switching from one task to another. That little white dot

in the left prefrontal cortex is what we saw

in everyone 20 years ago and what we see in low multitaskers now.

That's a part of the brain used for stopping decision-making, etc.

Okay, the yellow is what we see among

high multitaskers, the extra brainpower

used by them when they are doing the same task.

That actually is the visual cortex. And what's remarkable about this

literally these people are in a dark metal tube

strapped down there, their head braced, there's no where to look. other than the

screen.

Yet they're asked to multitask, they immediately start scanning the

environment.

And as a result, do much worse in their thinking.

So this becomes a very powerful suggestion that chronic multitasking is

rewiring

the brain of kids, increasingly adults,

and has consequences.