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PROFESSOR: In a way, I would
say most of this course up
until today, or maybe the memory
lecture, was about how
brilliant the human
mind and brain is.
How the visual system is so
brilliant nobody can make a
machine that sees so well.
We didn't talk too much
about physical action.
But how we move in the world,
how we act upon the world,
there's no robot that can
compete with you.
Language is far beyond computers
to be nearly as
sophisticated as you are,
as a five-year-old is.
So in all those domains, we
mostly think about in terms of
psychology or brain function,
how is it that we're endowed
with such amazing capacities?
When it comes to thinking, one
of the highest forms of human
activity, thinking, hard problem
solving, edges of
creativity, that kinds of thing,
it's something we have
a huge respect for, something we
wish for, something that we
know is a very, very
valuable tool.
But psychologists have
emphasized the
traps we can fall in.
I mean in a way what's easy
for us is what the brain
empowers in us.
It's easy for us to recognize
objects or faces
or move in the world.
When we feel something is hard,
like thinking hard, for
problem sets or global warming
or other things that are hard
to think about, then we know
that we're sort of leaving the
apparatus that's easy for us
and we're entering into a
hazardous, difficult form
of our mental lives.
So, I'm going to show you
a video for a moment.
Because the other fun thing is,
and maybe this is true of
all of us in different ways, all
the time, we often don't
recognize, we often don't
recognize when we're thinking
not as well as we might.
So this is a trap.
So I'm going to show you, the
original punking TV show, this
was called Candid Camera.
It's pretty old.
So this is a clip from there.
And here's a couple people asked
to do a school problem,
7/8 divided by 3/4 and
how many square
feet in a square yard?
And what's kind of funny about
it in my mind is, not only
that the people are wrong, but
how wrong they are and how
much they don't realize
sometimes how wrong they are.
I mean what's impressive about
this is that not only are the
people wrong, but they don't
say like, I forget.
They just start to give answers,
throwing out numbers.
And so how different are
all of us in that?
So some of these again
are on the internet.
And this is an MIT audience,
which is about the hardest
audience to pull this off.
And at Stanford, I could pull
this off much better.
So some of these won't go as
easily as they might for other
typical audiences.
Here we go.
Two train stations are a
hundred miles apart.
At 2:00 PM one Saturday
afternoon, the two trains
start toward each other,
one from each station.
One travels at 60 miles
an hour, the other
at 40 miles an hour.
Just as the trains pulls out
of their stations, a bird
springs into the air in front of
the first train, and flies
ahead to the front
of the second.
When the bird reaches the
second, it turns back, without
losing any speed, and
flies directly
toward the first step.
Doesn't this remind you of all
the high school physics
problems you had earlier?
Where's the frictionless
pulley?
The bird continues to fly back
and forth between the trains
at 80 miles an hour.
How many miles will the
bird have flown
before the trains meet?
It's a little bit of a trick.
Because the answer is told to
you directly, pretty much.
So 100 miles apart.
How long will it take for the
trains to reach each other, if
one is 60 miles an hour and
one is 40 miles an hour?
AUDIENCE: Hour.
PROFESSOR: Hour.
So how many miles an hour
does the bird fly?
AUDIENCE: 80.
Easier than you think.
So those are the kinds of ones I
just showed that people kind
of get themselves into
their thinking cap.
And it's a trick.
Here we go.
I need somebody who is willing
to, at their chair,
just call out words.
Thank you very much.
Here we go.
In English, many words are
pronounced somewhat
differently depending on the
way they are spelled.
But here we go.
Can you give me a synonym for
people or family, a word that
people would often
say for that?
I'll give you one.
Folk.
Now, I know this is
a history quiz.
But I'll help you.
I wouldn't know the answer
to this, necessarily.
Can you give me the name of an
American president at the time
of the Mexican War?
And I'll give you a hint.
It rhymes with folk.
AUDIENCE: Polk.
PROFESSOR: Polk.
Everybody can help.
Everybody help.
One, two, three.
Can you give me the name of the
word that means egg white?
AUDIENCE: Yolk.
PROFESSOR: Aha.
No.
Is the yolk, the egg white?
I know.
It's a pretty hilarious course.
Thank you.
So this is an example
of what people
call functional fixedness.
Your mind is going
a certain way.
And you're on a certain pace.
And all of a sudden when you
need to put the mental break
on, your habit of thought takes
you a slightly wrong
direction, on a very
superficial test.
Thank you very much.
Here's an experiment.
In 10 minutes, only about 39%
of people solve this.
You go into a room like this.
The strings are too far apart.
You have stuff around here.
And your job to tie the
strings together.
What do you do?
AUDIENCE: Stand on the chair?
PROFESSOR: Standing on the chair
is an interesting one.
Let's pretend it doesn't work.
It wouldn't.
It would get you up, but they'd
be far apart still.
It could.
Let's pretend it doesn't.
You'd have to be there,
to be convinced.
You know what I mean.
It mean depends on the angle.
AUDIENCE: [INAUDIBLE].
PROFESSOR: Sorry?
AUDIENCE: Tie it to the end.
PROFESSOR: Ah.
So you're one of the 39%.
So the idea is, if you tie for
example, the pliers onto the
thing and get it swinging, you
could catch it, right?
So why don't people come up with
that answer very easily?
PROFESSOR: Because what
are pliers for?
Pliering.
They're not for swinging
ropes.
So again, the word they use
is functional fixedness.
You know what a plier is for.
It doesn't seem like a good
candidate to do this job.
Here's another one.
You walk into a room and there's
a door that's closed
behind you.
And you see these things
on a table.
And you're asked, could
you support this
candle on the door?
About 23% of people
get this, in 1945.
What do you do?
This is just like all
the spy movies.
Yes?
AUDIENCE: [INAUDIBLE].
PROFESSOR: Sorry?
AUDIENCE: Put the tacks through
the width of the door.
PROFESSOR: Yeah, through
the width of door
would be pretty good.
It's not really supporting
the candle, but it
could get the job done.
That's not a bad thought.
These are all good thoughts.
If it were me, I wouldn't
be close.
So that's better than I do.
Yeah?
AUDIENCE: Take out the tacks
and then tack the base.
PROFESSOR: Have you
see this before?
No.
Excellent.
As I tell you, MIT's audience
is not an easy audience.
The idea is that you dump the
tacks, and then stick the tack
into the back of
the empty box.
Nice platform for a candle.
Why don't most people
think about that?
Because what's the
job of the box?
To hold the tacks.
My job is to figure
out this problem.
You hang on to the tacks.
And in fact if they do the same
experiment, but just put
the tacks next to the
box, a lot of people
get it right away.
Because now that box, it's
yearning to support something.
It no longer has a job.
It's an unemployed box that you
can stick onto the door
and support this.
Your mind just gets stuck with
thinking the box is a holder.
It's not a platform.
This is the original-- and
you've seen this so
many times by now.
This is one of the original,
thinking outside of the box
things, where you're supposed to
connect the dots with four
straight lines without
lifting a pencil.
Some of you know this.
Some of you are figuring
out on the spot.
But I'll just show you.
So there's an answer.
The other ones are similar.
Why do so many people
get stuck in this
and not get it done?
Because they don't
like this part.
And they don't like this
part, because it's
drawing outside the box.
They're always looking for the
connections within the box.
And it seems cheating in some
sense to draw outside the box.
There's an intuition, like with
the box with the tacks,
that you're supposed
to stay in there.
So if they get no information
in this study, practically
nobody solved it,
in a given time.
If they get a hint, you
can draw outside the
square, that helps.
But then, outside the square
puts again, the first line.
They're still only half
the time getting it.
Because you've got to go
outside a second time.
So it gets a lot of information
to get comfortable
with finding a way to do this
that's completely within the
rules, but not the way you
intuitively feel might be the
right way to do it.
So those are all examples of
functional fixedness, where
you have a certain belief about
what's going on and it's
hard to overcome that to solve
a problem in a novel way.
Another thing that people think
about as the way to
overcome some of these problems
of thinking about
problems is different
representations that let you
take a different look at
a problem to be solved.
So picture a large
piece of paper, a
hundredth of an inch thick.
Now, in your imagination,
fold it once.
You have two layers.
Continue to fold it on
itself 50 times.
It's true that's it's impossible
to fold it in
place, such a piece of
paper, 50 times.
But for the sake of the problem,
imagining that you
can, about how thick would the
50-times-folded paper be?
And everybody's first intuition
is, well, how thick
can a piece of paper be?
Of course, this is a
hypothetical problem, not an
actual paper problem.
But if you do the
math, it's big.
So here's another one.
One morning, exactly at sunrise,
a Buddhist monk began
to climb a tall mountain.
A narrow path no more than a
foot or two wide, spiraled
around the mountain
to a glittering
temple at the summit.
The monk ascended at various
rates of speed, stopping many
times along the way to rest
and eat dried fruit he
carried with him.
He reached the temple shortly
before sunset.
After several days of fasting
and meditation, he began his
journey back along the same
path, starting it at sunrise
and again walking at variable
speeds, with many
pauses along the way.
His average speed descending
was, of course, greater than
his average climbing speed.
Show that there's a spot along
the path that the monk will
occupy on both trips
at precisely the
same time of day.
So that sounds moderately
hard.
But if you draw the
picture, so we
went and get an equation.
Now, we have a pictorial
representation.
You can see there has to be some
moment of the ascending
and descending path that
cross in time.
You don't know what
it's going to be.
But there has to be some
moment in time.
And maybe that's obvious.
But for a lot of people it seems
stunningly complicated
that you could even
demonstrate that
in any way at all.
Here's one you could
think about.
Suppose you are a doctor faced
with a patient who has a
malignant tumor in
his stomach.
It's impossible to operate on
the tumor, but unless the
tumor is destroyed the
patient will die.
There's a kind of ray that can
be used to destroy the tumor.
If the rays reach the tumor all
at once, with sufficiently
high intensity, the tumor
will be destroyed.
Unfortunately, at this high
intensity the healthy tissue
that the rays pass through,
will also be destroyed.
At lower intensity, the rays
are harmless to healthy
tissue, but they don't affect
the tumor either.
What type of procedure might be
used to destroy the tumor
with the rays, and at the same
time avoid destroying the
healthy tissue?
Now, if you know the answer to
this, don't jump right up.
Give other people a few
moments to puzzle.
About 10% of people solve this
in a small unit of time,
before the Internet.
And so, what's the answer
though, for those of you?
Yeah, I see some
hands, I think.
Go ahead.
Did you want to say?
AUDIENCE: [INAUDIBLE].
PROFESSOR: No.
Exactly at the spot, sir.
AUDIENCE: [INAUDIBLE].
PROFESSOR: Yeah.
Have several weak ones aimed
to converge at the tumor.
I saw your hands.
So the idea is to have several
different rays, each of which
are weak enough not to
destroy the tissue.
But when they converge spatially
at the tumor, they
would sum enough to
destroy the tumor.
That's the problem-solving
answer to this.
So knowing that, here's another
kind of a problem.
A dictator ruled a small country
from a fortress.
The fortress was situated in the
middle of the country and
many roads radiated
outward from it,
like spokes in a wheel.
A great general vowed to capture
the fortress and free
the country of the dictator.
The general knew that if the
entire army could attack the
fortress at once, it
could be captured.
But a spy reported that the
dictator had planted mines on
each of the roads.
The mines were set so that small
bodies of men could pass
over them safely, since dictator
needed to be able to
move troops and workers about.
However, any large force would
detonate the mines.
Not only would this blow up
the road, but the dictator
would destroy many villages
in retaliation.
A full-scale, direct attack
on the fortress seemed
impossible.
Does this problem remind you of
the other problem, I mean
back-to-back, like this?
He divided his army up
into small groups.
Now, they're small enough per
path into the castle.
And they converge on the
castle, like the X-rays
converged on the tumor.
So this is reasoning
by analogy.
We have problem solving
approach.
Divide your resources
spatially.
Have them meet at the same time,
and converge in a way
that's effective.
So what you might call the deep
structure of the problem
is the same, with the surface
story being different.
One is tumors and treatments.
But there's a strict analogy.
Capturing the castle is like
destroying the tumor.
The fortress is like the tumor
that you want to get to.
The army is like the
rays and the
general is like the doctor.
So if it is back-to-back like
this, where I just said,
here's a problem.
And here's a problem
just like that.
Everybody says, well, send the
troops on the different paths
and have them converge
at the same time.
If you don't say that though, if
you don't tell people this
is the same, use
the same rule.
If you don't tell people that,
only about a third come up
with it spontaneously.
If you just make a little bit
of an effort not to make it
completely obvious that
it's the same problem.
You just wait a little bit.
So the surface differences,
the war story versus the
medical story, will mostly throw
people from recognizing
the analogies.
People recognize surface
analogies all the time.
If we have war in the Middle
East now, from the US
perspective there's analogies
to Vietnam, a war and a war.
But other kinds of analogies
across situations, people have
a hard time mapping, if the
surfaces look different.
And here's an example where they
gave people two problems
of a certain kind.
And they said as part of the
experiment, and here's a
classroom demonstration.
If it's immediate, they
sort of get it.
But if they wait just a little
bit, and they move from one
room to another room, they don't
apply the rule at all.
So it's very tricky.
We would like to think well,
gee, we know all kinds of
things about the world, that
we can bring in a mental
toolkit to solve problems,
all kinds of ideas.
But if the problem doesn't look
the same as the prior
problem, people have a hard
time spontaneously saying,
there's an answer I know, and
I can apply it to the
situation, unless it's really,
really obvious.
People don't transfer deep
solutions very easily across
what looks like different
situations.
Something different.
The instructors in a flight
school adopted a policy of
consistent, positive
reinforcement, recommended by
psychologists.
And we know we're very
suspicious about
psychologists, right?
But you have to imagine the
instructor went to some
classroom and somebody said,
positive reinforcement
is the way to go.
They verbally reinforced each
successful execution of a
flight maneuver.
After some experience with this
training approach, the
instructors claimed that
contrary to psychological
doctrine, high praise for good
execution of complex maneuvers
typically result in a decrement
of performance on
the next try.
Are they correct?
So you understand, you have to
have in your mind all the
military movies where
there's a really
tough sergeant training.
The other one that yells at
you to make you succeed.
But for half the movie, you
don't know if the sergeant
will break you or make you
into a better woman or a
better man.
So he's barking orders.
And some psychologist says,
well, you should really think
about saying nice things to
these people, because that's
encouraging.
Errgh.
Somebody does a flight
maneuver and does
a really good job.
And he goes, that's awesome.
And then the person goes
up and does worse.
And he goes aargh, you're
all terrible.
So what's happening?
Yeah.
AUDIENCE: It must-- the person
typically does really well.
Doing really well one time isn't
indicative of really
well the next time.
PROFESSOR: It's even worse
than that, right.
So all of us have in us a
range of performance.
We know that.
If you do sports, if you do
research, if you do anything,
some days we're at
our average.
Some days, we're not so good.
Some days, we go wow, that
was pretty good.
We all have a range of
performance that's possible,
our average performance, our
best days, our worst days.
So you just went up
and you did an
awesome flight maneuver.
Is that your average one or
is that a peak example?
It's a peak example.
Statistically, what's the
likelihood of your next one
going to be, better or worse?
Worse.
You can't always be at your
best, because you'd sort of go
into infinite excellence.
You have a range
of performance.
In the NBA, what's a
really good score?
30 points is really good.
That's the average though,
of the best players.
They don't go out and go,
I got 30 tonight.
And tomorrow, I'll get 32.
And by the end of the season,
I have like 180
points every game.
Even if you're on the
Miami Heat, you have
to do a good job.
So do you understand?
So here's another example.
Parents of very famous,
successful kids, are they
mostly super-famous and
super-successful?
Or do we mostly read about them
and go whoa, that's a
tough deal, what
happened there?
What's your impression?
Let's ask this question--
and if you are facing
these burdens.
If your parent wins a Nobel
Prize, what's the odds that
you win a Nobel Prize.
Small.
And they go oh, the
underachieving kid.
All the pressure from the parent
to do really well, with
a Nobel Laureate
as your parent.
Well, maybe.
Maybe your parent is berating
from kindergarten on saying,
if you don't eat your peas and
carrots, you won't win a Nobel
Prize, like I. That's
a possibility.
We can't rule it out.
But if somebody in your family
wins a Nobel Prize, what's the
odds that other people in your
family will win that.
PROFESSOR: Yeah.
So we call that regression
to the mean.
If you have an outstanding
example, a person who wins a
Nobel Prize, everybody around
them is not likely to win.
If you have an outstanding day
at what you do, like a really
good day, the next day is
likely to be worse, just
statistically.
So what's happening with
this flight instructor?
This is a very powerful and
important idea, that
intuitively often, what's
happening with the flight
instructor?
Of course if the guy does
awesome, he's going to do
worse the next time, every
single time, practically,
statistically.
So we can think about this,
regression to the mean.
Here's a standard
distribution, bell-shaped curve.
Here's the mean of whatever
you do, how well you shoot
baskets, how well you study for
a test, how well you wrote
a paper, how well you helped a
friend who needed consoling.
You pick your thing.
Some days you do a medium job.
You're average.
Some days you really impress
yourself with how you did.
And some days, you're pretty
shocked at what a miserable
day you had.
Does that makes sense?
So if you had an awesome outing,
by average, the next
outing is going to be less good,
regression to the mean.
So one place that this has been
done over and over and
over again, and somebody
help me out here.
This could happen
in any sport.
But especially in basketball,
people talk about a hot hand.
So some of you are sports
enthusiasts.
Probably some of you are not.
So a sports enthusiast, will
you please help me describe
what a hot hand is
in basketball?
Help the rest of the class.
Oh, thanks.
AUDIENCE: You think you're on a
hot streak just because you
made a couple baskets in row.
But they do the statistics and
then it ends up being that
they're just overconfident in
their shots, since they are
shooting more shots
in the end.
PROFESSOR: So people
have a saying --
If you watch a basketball game,
it's incredibly how
often the announcer will
say, oh, player x, he
or she is on a tear.
They're so hot.
Pass that ball to that person.
They're so hot.
They shoot a three-pointer.
And they come down and they
shoot a three-pointer.
And they say, why are
you passing the
ball to that person?
They're so hot.
And some players are known as
streaky players, who go out
and have just awesome nights.
You hear this in the sports
all the time.
I can't tell you, the end of
a close March Madness game,
they're always saying,
pass it to this guy.
Because this guy is on a
streak in this game.
So they can do the statistics.
How would you do the
statistic to know
whether streaks actually--
streaks exist.
Sometimes you do two baskets
in a row or five.
Or you miss five in a row.
There are runs, like
heads and tails.
But the question we're asking
is, if you made a shot, does
that an increase in any short
run, the probability that
you'll make the next shot?
That would be the streak.
That would be the hot shooter.
So you can go do statistics.
And they did it.
Psychologists have done it on
many teams, in many leagues.
They did every single shot of a
Cornell basketball team, the
entire season.
But they've done it on
many other teams.
There is no such thing
as a hot streak.
There is no such thing
as a hot streak.
Of course, you have small runs,
where people have a lot
of good shots.
Another day, they'll have
a lot of bad shots.
But the probability of making
any one shot is no higher or
lower, given the probability
that you made the prior shot.
They're completely
independent.
And nobody can find statistical
support for any
kind of streaks in sports,
except of course you have huge
distributions.
So sometimes a person
will have an
exceptionally good or bad night.
So this is kind of like that.
And you will get this.
Suppose that you have a normal
penny with a head and a tail.
You toss it six times.
Which is these outcomes
is most likely?
All the same.
You're absolutely right.
But why do people tend not to
like a), mostly, who haven't
studied probability much?
They don't like a).
Why don't they like a)?
Most people, most of the time,
as a random thing?
Yeah?
AUDIENCE: It doesn't
look random.
PROFESSOR: It doesn't
look random, man.
A) can't be random, right?
But we know that we have
short runs of anything.
And each of these are
independent outcomes.
That's exactly what you got.
We did this example before.
But there are 30 people
in the group.
You get the month and date of
each person's birthday.
What is the approximate
probability that two people
have the exact same birthday?
And most people will say, oh, I
haven't met that many people
on my birthday.
Not that high.
But it's actually 70%.
Because it's any two
in the group.
It's not you.
It's any two in the group.
And that increases it to 70%.
Here's one we haven't done.
Imagine a college in which the
average height of men is 175
centimeters.
You randomly measure the
height of three men.
Which of these two outcomes
is more likely?
And I'll let you think about
this for a moment.
John at 178, Mike at 170, and
Bob at 176; or John at 177,
Mike at 177, and Bob at 177?
Which is more likely,
or can't tell?
AUDIENCE: [INAUDIBLE].
PROFESSOR: I heard a
B. Is it obvious?
Let me tell you.
It's the same concept we've
been talking about, about
distributions and means.
So here's the average, which
you are given as 175.
So these guys are closer
to the average.
Height is distributed
in a normalized way.
So here's the three people, who
are red dots, the equal
heights, 177, and
177, and 177.
Here are the heights
of the blue.
There's more people in this
part of the distribution.
So it's actually more likely to
get this than this, about
40% more likely.
Because you're sampling from
closer to the mean.
And there are more people
near the mean.
Does that make sense?
But people don't like that.
Overwhelmingly, if you ask
people, they like the top
answer, because it just doesn't
feel right to get
three people of equal height,
in a random way.
And you could say, what do you
mean it doesn't feel right?
We can do the math or we can
show you the picture.
And we can all agree, I think,
that that's correct.
What do you mean it doesn't
feel right?
And that's what people mean
by the difference between
algorithms and heuristics.
This is work from Kahneman and
Tversky, that won a Noble
Prize for Danny Kahneman.
Tversky passed away.
Which is that humans could
figure out many things
algorithmically.
You can do the probability.
But as an intuition, for many,
many, many people, even
educated people who know a
lot about probability.
There's an intuition that we
have about things, heuristics,
a feeling we have
about things.
Like the odds of this
are almost nil.
And we go by that feeling,
instead of by being the
rational analyst that
we might be.
Here's one.
You'll get this one, I think.
A nearby town is served
by two hospitals.
About 45 babies are born each
day in the larger, about 15 in
the smaller.
Approximately half of
the babies are boys.
However, the exact percentage
varies day to
day, of boys and girls.
Some days, it's higher
than 50%.
Some days, lower.
For a period of a year, both
the larger and the smaller
hospital recorded the number of
days in which more than 60%
of the babies were boys.
So a disproportionate
number were boys.
Which hospital do you think
recorded more such days?
The answer is about the same.
The most common answer
is about the same.
But because of the law of small
numbers, you're going to
get more weird samples in
the smaller hospital.
Because it'll be a less
of a distribution.
You'll get more weird stuff.
Here's one.
It's a little dated, in terms
of the language used.
But they would give people
an example of this.
Linda is a 31-year-old, single,
outspoken, very bright.
She majored in philosophy
as a student.
She was deeply concerned with
the issue of discrimination
and social justice and also
participated in antinuclear
demonstrations.
And then rank the options in
terms of their likelihood.
In describing Linda, I'll give
a ranking of 1 to the most
likely option and a ranking of
8 to the least likely option.
So people go through this.
I mean you're sort of just
making up stuff.
Having said this, I think people
go around all the time
having impressions of people in
their head, what are they
really like, what are
they really about.
But they do this
kind of thing.
And here's the interesting
element to the result.
People on average, are more
likely to endorse the
statement, Linda is a bank
teller and active in the
feminist movement, than Linda
is a bank teller.
Now, why logically is that a bad
idea, as you're guessing
about Linda and what
you might do?
Why is it logically a bad idea
to pick h, more than f?
AUDIENCE: [INAUDIBLE].
PROFESSOR: Right.
Yeah.
Yeah.
Just logically, heuristically,
algorithmically, right, sorry,
it's more likely you'd
be correct saying
she's a bank teller.
She's a bank teller and shes--
But why do you think more
people pick this one?
Because of your intuition.
So people think, well
this is a person who
might be like this?
So they go for the bigger
description.
And not just unsuspecting
undergraduates, but also
first-year grad students in
stats courses, and also
doctoral students in decision
science programs
and business school.
It's not, with more training
you can avert these errors.
But everybody has it in them
pretty easily to be seduced by
intuitive heuristics of
reasoning, rather than
algorithmic analyses.
Availability is kind of fun.
So this is a slow one.
This example is a little
work, for an example.
Some experts studied the
frequency of appearance of
various letters in the
English language.
They studied a typical passage
in English and recorded the
relative frequency with which
various letters of the
alphabet appeared in the
first and the third
positions of words.
For example, in the word
"language," appears "L"
appears in the first position
and "N" appears in the third.
In this study, words with
less than three
letters were not examined.
Consider the letter "K." Do you
think that the K is more
likely to appear in
the first position
or the third position?
Now estimate the ratio for the
number of times it appears in
the first versus the third.
So it could be even, 1:1; it
could be more often in the
third position, like 1:2; or it
could twice as often in the
first position.
Any feelings?
Just for fun, who thinks K
appears more often in the
first word than the third?
Just for fun.
Help me out here.
Hands up.
If you have to pick
one or the other.
You have to pick one
or the other.
How many people like in
the third position?
Anyway, so here's what
happens mostly.
Not your estimate, but
the estimate of
students in larger samples.
2:1, they like K in the
first position.
It's really 1:2 in
the dictionary.
Why do you think on average,
people tend to go for K in the
first position?
So now we need somebody who's
willing to say something, give
some answers out there.
Yeah?
AUDIENCE: Because it's easier
to think of words that start
with K than it is--
PROFESSOR: Yes.
So help me out.
Let's do this for one second.
Somebody call out a
K word, any word?
AUDIENCE: Knight.
PROFESSOR: Knight.
Another word?
AUDIENCE: Kind.
PROFESSOR: Kind.
Another word?
AUDIENCE: Kangaroo.
PROFESSOR: Kangaroo.
Excellent.
OK, very good.
OK, quick, a K in the
third position?
AUDIENCE: [INAUDIBLE].
PROFESSOR: Oh, you guys are--
I should have done
it differently.
So now we're talking about the
heuristic of availability,
that we sort of think that how
common something is and then
in some ways, how important
something is, by the ease with
which it comes to mind.
It's easier really to think of
words beginning with K, then
having K in the third
position.
Here's a question.
How much more likely are you,
and I don't know the answer to
this, but you can figure it out,
to drown in the bathtub
than to die from a terrorist
attack in the United States?
Obviously since 9/11, terrorism
has been a a huge
issue in our county,
a huge issue.
But in the US, what
do you think?
Much more likely for people to
die drowning in a bathtub than
terrorist attacks, including
9/11, for the 2000s.
So why is it, why is it that you
have constant discussion
about terrorism?
Why is it that you take off your
shoes and can't take much
of your toothpaste
on the airplane?
And yet nobody is talking to
you, saying, please exercise
caution when you go
into the bathroom.
And please have those things,
those sticky things that make
it less likely to slip.
Do you get much of that?
Do you go to the airport and
they say, those shoes look a
little slippery, in case
you go into a shower.
So think about this, which is
the real danger, just in a
practical way, and why do people
worry so much, and not
for bad reasons, about
terrorism?
What's the difference
between them?
And you can think of
more than one.
Yeah?
AUDIENCE: You hear about
terrorism on the news, but you
don't hear about anyone drowning
in the bathtub.
PROFESSOR: That's huge.
Availability is huge.
The news is a very powerful way
in which we think that's
what the world is full of,
terrorism in the US.
We hear about terror groups that
are found, terror cells
that are found.
We'll hear about homicides a
little bit, in the local news.
But you just never hear about,
unless it unfortunately
happens to somebody you know
personally, somebody slipping
and dying in the bathtub.
And it does happen.
But you don't hear
about it much.
It's not available to you.
Yeah?
AUDIENCE: We're most scared of
things that are foreign to us
even if they are
less dangerous.
Like we'd be more likely to
drink a clear fluid that was
more dangerous than something
that looks scary.
PROFESSOR: Part of it is, what
you're saying, there's a sense
of foreignness to the terrorism
that we don't
understand.
Maybe there's a sense
of passivity.
We feel like we could do
something about the bathroom.
We can't do something about
an airplane being
driven into a building.
These things are complicated.
But it's fascinating what people
think is scary versus
what by any rational analysis,
is dangerous.
Here's another kind of way that
people easily struggle
with numbers and thinking
about what's
dangerous and not.
So imagine you're a physician
and you're presented with this
information.
And let's hypothesize
that it's true.
Somebody comes in
with dizziness.
And they say, I'm worried
about a brain tumor.
They go to your neurologist.
And the neurologist says well,
here we have some statistics
over the last two years, whether
somebody turned out to
have a brain tumor or not,
present or absent; and whether
they were dizzy or not,
present or absent.
So you can make a 2 x 2 cell,
about they had a tumor and
they reported dizziness; they
reported dizziness, but it
turns out they had the
tumor; and so on.
So here's the question
for you.
Is being dizzy something
to worry about in
terms of having a tumor?
Should you be worried if you're
dizzy, that you might
have a brain tumor,
by these numbers?
So what do you think
most people think?
You have to make
a quick answer.
You're one of those doctors on
House, who's going to get
berated in a moment.
And you go, whoa, 160, bad.
That's what a lot
of people feel.
And by the way, there's a lot
of concern in medicine about
how doctors convey risk to
patients, as patients pick
what kind of treatment
they want.
Because it's exactly what
we're talking about now.
It's the exact way that you
convey to a patient, the risk
they're facing or their family
member is facing among
different treatment options.
So is dizziness associated
with a brain tumor?
And the answer is no, because
if you do the probabilities,
so the probability of
a tumor is 4:1.
So here's whether you have
the tumor, brain tumor.
And it's one out of four, and
it's one out of four.
The odds are identical.
But you're impressed by this
absolute, big number.
Intuitively, almost everybody
is, almost all the time.
Here's another one that's
a bit more subtle.
It comes up all the time
in medical testing.
It's come up in things like
discussions about how often we
should test for, if you're a
male, for prostate cancer when
you get older; if you're a
female, for breast cancer.
So these kinds of things come
up all the time in decisions
about should you get the tests
or not, and so on.
So imagine now, a hypothetical
syndrome, is a serious
condition that affects
one person in 1,000.
Imagine also that the test to
diagnose the disease always
indicates correctly that
a person who has it,
actually has it.
So if you actually have the
disorder and you get a yes,
you will always be identified.
So that's a good test
in that way.
Finally, suppose the test
occasionally misidentifies a
healthy individual as having
that disorder.
So that's a false positive.
The test is a false positive
at a rate of 5%.
Meaning the test wrongly
indicates that the virus is
present in 5% of cases
where the person does
not have the virus.
So if you have it, it's
always correct.
But 5% of healthy people will
be misidentified on the
initial test.
Choose a person at random,
administer the test, and the
person tests positive
for that syndrome.
What is the probability the
person really has that?
This is the kind of medical
testing topic that goes on all
the time, all the time.
What do you think most people
are going to say?
AUDIENCE: 95%.
PROFESSOR: Yeah, 95% exactly.
Because he said well, 5%
of the time it's wrong.
But that ignores the base
rate of this order.
Because if there's 1/1000,
then if the other 999 are
tested, then you have
about 0.5 times 999.
That means for every 51 who are
tested, only one has it.
So the answer is
only about 2%.
Because the odds, the prior
odds, that you have
it are so, so low.
So that comes into the
likelihood that it's an
accurate test and the
false positive rate.
So again, people's intuition
when they hear, their
intuition is there's a 95%
probability that the person
has the disorder.
It's really only about 2%, given
the low known base rate.
And if all this is whizzing by
you a bit, I know I'm going
through it pretty fast.
But you can think in two ways.
You can also think you're a
patient being told this.
You're not going to get an
hour long lecture on
probabilities either.
So how this is communicated to
physicians, for example in the
medical area and families, is
a really big challenge.
So we talked about two
heuristics, that people liked
things to look random, that we
tend to go for what we often
hear about and imagine that's
how frequent or dangerous
something is, in a very
broad, intuitive way.
Anchoring and adjustment,
here's a fun one.
So here's the experiment
they did.
They went to people, like in
courtyards around things that
are around Stanford,
actually mostly.
And they had them do
the following.
They gave them either this
problem or this problem.
And here's what happened.
If they got this problem, and
they quickly had to guess the
answer, they came up
with this many.
This was their average estimate
and this was the
average estimate.
So the first thing we can agree
upon, regardless of the
fact that everybody is
completely underestimating the
actual answer--
that's almost not the point--
regardless of that, look
at this estimate.
This rapid estimate is four
times greater than that.
Why is that happening?
You're only getting
one or the other.
But why is that happening?
This is the heuristic of
anchoring, how people come to
quick decisions.
If we go, 8, that's a
pretty big number.
8, we're talking some big
numbers here, right now.
They don't even get that they're
going to get to here.
They start with 1 and 2.
They go, we're talking about
a pretty small thing.
But I can't quite calculate it
out, because it's too hard to
calculate it out
for most of us.
This is going to be pretty small
by the time-- so they
are already thinking small.
They are already thinking big.
So now you know why, when you
go negotiate for your salary
somewhere in the future, if
you have any negotiating
power, start with
a big number.
And the person who is
negotiating with you knows
that too, and in fact is often
more practiced than you are.
So here's a practical clue.
Start with a big number.
Because that's the number where
people's minds are.
And I'll show you several
more examples of how
ridiculous this is.
But when there's no true, exact
number that you can
quickly come up with, what's
the fair salary for you to
get, the first year out of MIT
in a job or something?
First number out there,
has a lot of power.
So here they made
it ridiculous.
This anchoring, that my mind
start somewhere and I kind of
stay in that neighborhood.
I don't recalibrate myself.
So they took a wheel of fortune,
a spinning wheel of
fortune, with the numbers
1 to 100.
It's clearly random.
Can't make it more obviously
random than that.
It stops somewhere.
And they say, we want you to
estimate the number of African
nations in the UN?
And most people don't
really know.
And there's some vague sense
that it's more than a couple.
But who knows how big
it is exactly.
So the number stops somewhere.
And here's the kind of
thing that happens.
First you say, is it more or
less than the number it
randomly stopped at?
Let's pretend it
stopped at 65.
Then average estimate was
45 African nations.
Let's say it randomly
stopped at 10.
Then the average estimate
was 25 nations.
What's happening?
Anchoring.
You say well, it's
more than 10.
But 10, I'm going to
go way up from 10.
Because that's way too low.
And I'll split--
going beyond 25 seems
hazardous.
You start at 65.
You go, whoa, that's
way too many.
But you're anchored.
And then you use don't
go down that much.
So that first number, when you
don't really know what the
right answer is, has an
incredible power over how far
you range from that, for
your best estimate.
Same idea.
Is the Mississippi
River longer or
shorter than 500 miles?
So they're giving
you the anchor.
How long is it actually
do you think?
Or another person is asked, is
it longer or shorter than
5,000 miles?
There's the anchor.
How long is it, do you think?
And here's the estimates.
They're both underestimating.
But they're moving towards
that number that was
completely randomly thrown in.
But it's not random
to the human mind.
We don't know what the right
number is, but we're going to
start in the neighborhood that
we first have any number
presented to us.
Framing.
Framing is arguably, together
with availability, maybe the
one that's the most interesting
in terms of how
powerful it is and how often
people use it to convince you
that their political position,
their corporate position,
their anything, is
the way to go.
And once you know framing,
you're empowered a bit to
think about that, because you
hear arguments made to you
about what to believe in
or what to support.
So here comes the framing.
Imagining the United States is
preparing for the outbreak of
an unusual South American
disease, which is expected to
kill 600 people.
Two alternative programs
to combat the
disease have been proposed.
Assume that the exact scientific
estimate of the
consequences of the programs
were as follows.
If Program A is adopted, 200
people will be saved.
If Program B is adopted,
there's a one-third
probability the 600 people will
be saved and a two-thirds
probability that no people
will be saved.
Which program do you favor?
So B is pretty complicated.
But A is pretty simple,
200 people might be
saved, will be saved.
So here's the exact same
scenario by lives and deaths,
given to a second group of
research participants.
If Program A is adopted,
400 people will die.
Do you see that if A is adopted,
200 people are saved,
equals 400 people will die.
It's the same thing.
There's 600.
You're really saying
the same outcome.
But that numerical identity
is treated by humans as
incredibly different information
on which to base
your decision.
And here's what happens.
If people are given this
scenario, which is explained
in terms of lives saved, 200
lives saved out of 600, 3/4 of
the time they pick it.
If people are given this
scenario, 3/4 of the time they
don't pick it.
It's the exact same choice.
But to be human, is to gravitate
towards something
where you save lives
and avoid something
where you lose lives.
Even though numerically, it's
the exact same outcome.
But people radically switch
which one they think is the
correct one, by the
framing of it.
By simply the way it's
described in
this most simple sense.
So does that makes sense?
I mean it's very powerful.
When people present to you
stuff, how do they present it?
Lives saved, lives lost; jobs
made, jobs lost; whatever you
want, money made, money lost.
We don't treat them
as two bits of
information that are equal.
We should.
That's the algorithm,
out of 600 people,
200 people make it.
But that's not how we
psychologically interpret it.
We go tremendously
by, we're drawn--
any answer that uses the word
"saves", is a positive thing.
And we're averse from any answer
that talks about bad
things, how many people
will die.
Even though they're
identical in the
consequence of life and death.
Is that clear?
Very powerful.
Here's another version of
it now, moving to money.
And it gives you another
feeling of this.
So you could think about
the top one.
Would you rather have
a sure gain of $75.
Somebody said, I'll give
you $75 right now.
Or you can have a lottery where
you have a 75% chance of
winning $100, so that's even
more, or a 25% chance of
winning nothing at all.
Another group of people
get this question.
We're going to take
from you $75.
It's a rough experiment
to sign up for.
Or you're going to be in a
lottery with a 75% chance of
losing $100, which is even a
worse loss, and 25% chance of
losing nothing at all.
So these are meant to be kind
of symmetric stories.
But one is expressed all in
terms of gain and one all in
terms of losses.
And when people are thinking
about gains,
they're risk averse.
I'm not going to give up
what's in my hands.
So 84% of the time,
they take that.
Even though this is sort of
formally similar because it's
a loss, now when it's losses,
people are risk taking.
Humans are very asymmetric.
If things are expressed in
gains, we're risk averse.
Let's do the safe thing.
I'm going to hang on to what's
already in my grasp.
If it's in terms of loss, it's
like, let's bet the house,
let's do any crazy,
wild thing.
Because losses are so bad
that I'll take any
chance to avoid a loss.
Even though rationally, the
choices should be about the
same, if we were machines
making choices.
Very big difference.
I mean when I first
heard about these
things, I was stunned.
Because it's huge.
Everything that we vote for,
everything that we support,
every decision we make about
careers, and policies that we
are for or against, are always
being expressed to us in a
framework like this.
Things that we can gain or lose
in our own lives, in the
world, in societies.
And you spin around so easily
by how they're framed.
Although now you
know something.
And you can think about them.
Here's just two odds and ends
things, that I thought were
kind of fun.
Other things that people find
kind of challenging to think
their way through, just because
of the way our minds
are constructed.
So here's a problem.
Jack is looking at Anne, but
Anne is looking at George.
Jack is married, but
George is not.
Here's your problem
to think about.
Is a married person looking at
an unmarried person, yes, no,
or cannot be determined?
The only reason I know the
answers to these is because I
have the answers to these.
The first time I see these,
I'm like, oh no.
So just for fun.
You can go by intuition and
maybe you worked it out or you
looked ahead.
How many people who haven't
looked ahead, say yes?
OK, there's some hands, 10.
How many say no?
Nobody.
How many say, cannot
be determined?
The answer is, that's good.
Most answer, 80% say cannot
be determined.
But the answer is this.
Think about this.
The answer is yes.
And here's why.
We don't know Anne's
marital status.
The other two are given.
So we have to figure out
Anne's situation.
Let's say she's married.
Then she's looking at
unmarried George.
Let's say she's not married.
Then Jack is looking
at unmarried Anne.
Is that OK?
This is what people in logic,
call fully disjunctive
reasoning, where if you work
your way through the
possibilities, you see
it has to work out.
But that's not our intuitions.
I mean you're a very
smart group.
So if it's hard for you, imagine
the rest of the world
is not as suspicious about how
to figure their problems out.
So it's just fantastically
interesting how the human mind
is brilliant at some things.
And for other things, it could
solve, it could solve,
intuitively, it's not often
going to happen.
We go by these shortcuts where
either we don't get the answer
at all or we come up with a
completely wrong one, because
of availability or framing.
Here's a quick one.
You'll get this fast.
It's fun.
A ball and a bat cost
$1.10 in total.
The bat cost a dollar
more than the ball.
How much did the ball cost?
All right, you guys are now,
you're very suspicious.
You're thinking it through.
Most people love $0.10.
But you can tell that's
not going to work?
Because then the bat would have
to cost $1.10 and the
total would be $1.20.
But a lot you were pulled to,
most of us to, having a $1.10,
because we don't quite
think it through.
There's $1.00.
There's $0.10.
And we do these shortcuts, these
heuristics, instead of
logically working
our way through.
One more example of this
kind of thing.
Because now we're going
to add one more
element just for this.
Imagine that the US Department
of Transportation has found
that a particular German car
is eight times more likely
than a typical family car to
kill occupants of another car
in a crash.
The federal government is
considering restricting sale
and use of this German car.
Do you think sales of the German
car should be banned in
the US or do you think the
German car should be banned
from being driven on
the US streets?
So here's one, given in this
study to US participants.
Or to do exactly the same
thing, but it's
not a German car.
It's a Ford Explorer.
So American participants, if
it's a German car, 73%, get
that car off the road.
If it's a Ford Explorer,
sorry.
If a German car, off the
streets, you get 73%, If it's
the American car, and Germany
is making the decision, only
40% of the people think that
Germany should do that.
Now, that's not purely logic.
What is that?
That's bias, right?
That's like, yeah, on my
streets, we don't want these
threatening machines
from overseas.
Germany, we've got to keep
that economy going.
Those Ford workers are really
doing a good job.
So of course most decisions
aren't hyperrational in the
way we've been talking about,
unknown people.
Of course they involve things
in the world that we already
have feelings about.
So you add that in and you can
see that making a truly
logical judgment is shockingly
hard, if anything is a little
complicated.
So let me turn for the last
little bit to what we think of
as some of the core parts of
the brain for higher level
thought, the struggle we have
between the best we have in
our mind and the traps
we can fall into.
And when we talk about that,
we tend to focus on sort of
three areas of the
frontal lobe.
So let me just remind
you of this.
So here's the frontal lobes.
And you could think of the
frontal lobe I think as the
business end of the brain.
Here comes visual information
coming in, auditory
information coming in,
touch coming in.
Somewhere back here,
would be taste.
So that's getting stuck in and
figuring out what's out there.
So the front half is the
business end of the brain,
acting upon the world.
Moving your hands, moving your
body, making decisions about
what you do.
Motor cortex, premotor cortex,
a guy's motor cortex.
This so-called lateral
prefrontal cortex, that's
higher levels of thought.
And this bottom part of
ventromedial or orbitofrontal
cortex, that we talked about
with Phineas Gage.
So Oliver Sacks, in Chapter 13,
talks about one example of
a woman who has a large tumor
in this ventromedial area.
So sometimes I think there's a
Roman philosopher who said
that life is composed of desires
and decisions, desires
and decisions.
So this part of the brain is
involved in desires and this
part in decisions.
And I'll show that,
roughly speaking.
So here's a woman who is a
former research chemist.
And she has a rapid personality
change, becoming
facetious, impulsive,
superficial.
And she a cerebral
tumor in this
ventromedial part of the brain.
When I see her, she's full
of quips and cracks,
often clever and funny.
Yes, father, she says to me on
one occasion; yes, sister, on
another; yes, doctor,
on a third.
What am I?
And then she make some jokes.
So she's constantly joking.
And she says, everything
means nothing.
Nothing at all, she says with
a bright smile and a tone of
one who makes a joke, wins an
argument, or wins at poker.
So she just finds that sort of
there are facts of the world,
but they just don't feel like
they mean anything.
Because a tumor is influencing
a part of the brain that we
understand to organize the
relationship between thoughts
and feelings, between thoughts
and feelings.
And that's a huge way about
how we go about the world,
what we think, what we feel.
We've put it into a formula
of some sense.
And that's how we act upon the
world, whether we help
somebody, or don't help
somebody, like somebody, or
don't like somebody.
All those sorts of things.
So when we think about behavior,
we normally think of
the challenge of getting
it going.
You get in your car and you
turn on and you accelerate
from 0 to 60.
But a really interesting thing
about the human brain is that
we have lots of habits, things
we acquire about how to deal
with the world.
So just as big a problem for
our brains is stopping the
course of action that's
no longer relevant.
So the frontal cortex both has
the job of initiating things,
but also stopping things.
And you can see it in a couple
of ways, I'll show you.
So here's an example
of a patient with a
frontal lobe injury.
They're drawn this scratchily,
by a physician.
And here's their exact copy.
Do you see they can't stop?
Here's again the model,
scratched out by the physician.
Look at the patient.
The patient can't stop.
So the problem's not starting.
The problem is stopping the
mental operation once it's
going and repeating.
And it's hard to put on
the mental breaks.
Here's an example of a
behavioral test of that kind.
And I remember this, when I was
testing patients in E17
and E18 here, I did
this a fair bit.
It's called the Wisconsin
Card Sorting Test.
And what happens is, you put
on four cards like these.
These are the key cards.
It's very mysterious when
you give the test.
You just put them down.
And you have a pile of
cards over here.
And you tell the person, your
job is to pick a card from
this pile and put it below
one of these cards.
And I'll tell you if you're
right or wrong.
And then use that information
to know where to
put the next card.
So imagine you are doing this
experiment, and if you're
color blind, there's
an extra issue.
I'll just warn you.
But you get this first card.
Where would you put it below?
Where could you put it below?
AUDIENCE: [INAUDIBLE].
PROFESSOR: OK.
That has an equal number.
That's one possibility.
What's another possibility, as
the rule by which you might
sort the card?
AUDIENCE: Color.
PROFESSOR: Color.
Yeah, that's green.
That goes with that.
What's another possibility
that you can see?
Shape.
You can say that's a plus sign,
that's a plus sign.
They all seem reasonable.
So people usually pick
one of those three.
And if they happen to pick the
one that I as a tester know
from my instruction sheet,
it's my job to reinforce.
Let's pretend it starts
with color.
If they do this, I go wrong.
I go, hmm.
And they pick another card and
they try something else.
They pick another card and
they try something else.
And after three or four
cards, people pretty
much get the color.
And then you go get
another card out.
You go right, right, right,
right right, wrong.
And when I did this, I was
approximately your age.
And most of the patients
I tested were older.
And they go like, sonny, look
back on your score sheet
because it's correct.
And I go no ma'am, no sir.
I'm sorry about that.
But it's wrong.
Because what you do is after
10 consecutive correct
responses, you switch the rule
from color to shape.
After 10 correct shape,
you switch to number.
And then you do that again.
So you switch the
rule after 10.
So it's a test of mental
flexibility, in a fairly
simple way.
Does that make sense?
They have to figure out
what the answer is.
Then they're zooming along.
And you go, no stop.
And you have to come up
with the next answer.
So here's what happens for
patients with frontal lobe
lesions, they make a huge
amount of what's called
perseverative errors.
So this is now the intellectual
analog of the too
many squiggles.
Once they get that first rule,
they can't stop that rule.
So they go color, color,
color, color, color.
They get about 10.
So you switch.
And they just keep doing it.
You go no, wrong, wrong,
wrong, wrong, wrong.
But they can't stop the rule
that worked in the first
place, without the prefrontal
cortex being intact.
So our mental flexibility seems
to depend tremendously
on prefrontal cortex.
And you can do the same kind of
thing in imaging, just to
make sure it's not just
a patient thing.
And again, when you have to do
this very same kind of task,
typical people activate
prefrontal cortex to do the
mental manipulation of the
simple problem solving task.
So we talked about
perserveration and its hard to
stop and mental flexibility.
With ventromedial lesions, you
get some weird things.
You get what they call
utilization behaviors.
So again, we're having this
idea what's the good thing
about having very
powerful habits?
Is it very good to have very
powerful habits, and we use a
different word for this,
when you read?
Yeah.
Because that's how you're
a fast reader.
You know how to read
words really fast.
Is it good to have very powerful
habits when you walk?
Yeah.
You don't want to go like, OK,
I'm moving the leg now.
Everybody get ready.
We're moving the other leg.
Because you could never get
out of the room very
efficiently.
So for many, many things, having
very powerful habits
are very strong.
But for other things, they're
not as good and you have to
put the brakes on.
So Lhermitte described patients
with ventromedial
lesions who came in,
saw in his office.
This was not a set-up
experiment.
He didn't expect this.
There was a hammer, a
nail, and a picture.
And the patient just
goes over, up.
And you could imagine, if you
go into the doctor's office
and you see a hammer, a nail,
and a picture, would you go
over and put up the picture?
No.
I mean you know that's what
you do with that stuff.
You know that's what's
going on.
But you go, that's not my place
to do it, even though
it's attempted to do it.
The patient could not help
himself but go do that,
literally go do that.
The most dramatic example was,
the patient walks in and sees
a hypodermic needle, pulls down
his pants, and injects
himself in the derriere.
So again, he knew that
was going to happen.
He knew that's the habit.
But you wouldn't go into a
doctor's office and start
using their stuff and
perform on yourself.
You understand.
The habits are completely
running the show.
And any kind of frontal cortical
control of those
habits has been eliminated
in these patients.
And here's a couple
more things that
are along that line.
So I need a volunteer, in your
seats, to try something with
me for a minute.
It's not bad.
I think I've traumatized
you in these examples.
OK, thank you.
If you had to answer this
question, and there's no
correct answer.
But let's just talk about
how you might do it.
How long is a man's
spine, on average?
AUDIENCE: About two feet?
PROFESSOR: And how did you
kind of come to that?
And that might be
right or not.
AUDIENCE: My back is roughly
two feet long.
My spine is--
PROFESSOR: Yeah.
It's got to be less
seven feet.
Because that's like the tallest
basketball players.
On average, it's got to be
more than a couple feet.
Something in that range.
OK, you just guessed
which it was.
Or how fast does a horse
in a race gallop?
Or what's the largest object
normally found in the house?
What do you think
that might be?
AUDIENCE: Fridge?
PROFESSOR: Help me out here.
AUDIENCE: A refrigerator.
PROFESSOR: A refrigerator
is a good one.
Anybody else?
AUDIENCE: [INAUDIBLE].
PROFESSOR: All those are good.
Is toaster a good answer?
No.
One more person.
Who's going to help
me out here?
One more example.
Come on.
One more example.
It's easy.
OK, thank you, Rich.
How many camels are there
in the Netherlands?
Now, nobody knows.
But tell me a thought process
roughly, so you would come up
with an estimate.
AUDIENCE: 100.
PROFESSOR: Yeah.
Because are you going to figure
there's a lot in the
Netherlands?
No.
Because there's no
desert, right?
Where might you find a few?
AUDIENCE: [INAUDIBLE]
PROFESSOR: On a ranch.
I haven't been to Amsterdam
for a while, so perhaps
there's a few loping around
in the canals.
And some zoo, some kids' petting
thing, who knows?
So, yeah, 100 sounds
good to me.
But frontal patients will
give really bad answers,
thousands or zero.
Or 12 feet for a spinal cord.
Or just something that
you go like, where
did you come up that?
You can do the Price Is
Right game with them.
They'll come up with more
ridiculous answers.
Here's just a graph.
These are bad answers for how
expensive something is, just
unreasonable answers
within these sort
of open-ended questions.
Or you can do more
formal problems.
The kind of problem
where you're given
a puzzle like this.
And your job is to move these
into a target state.
And so to get over to here,
you've got to move the blue
guy over here and whatever, in
a different number of moves.
That's planning ahead
and problem solving.
Patients with frontal lobe
lesions make many mistakes on
these kinds of tasks.
So the last thing I want to
talk is a little bit about
Phineas Gage kind of lesions.
And we'll get in a moment to a
comment about serial killers.
So Phineas Gage had
this huge injury.
We talked about him
already in the
ventromedial prefrontal cortex.
There's some other patients
who have orbitofrontal
lesions, who have
been studied.
And let me tell you
a little bit about
what's known about them.
And I can tell you this is the
part of the brain that's been
most implicated in psychopaths,
some of whom turn
out to be these serial
killers.
One measure they've used in
these experiments is galvanic
skin response.
That's the kind of
stuff they use in
polygraphs, lie detectors.
They put them on your skin and
what they measure is responses
that are related to
sweat glands.
So it's a measure of emotional
reactivity, basically.
Here's a really interesting
thing.
If we measure your galvanic skin
response and we show you
faces of people you know, family
members, friends, and
so on, versus people you don't
know, you get a galvanic skin
response for the people
you know, because
they matter to you.
It's an emotional response,
versus faces you don't know.
You even get that kind of
strikingly in several studies
in patients with
prosopagnosia.
So we talked about those
patients who can't recognize
people by their faces.
But something in them still
recognizes who's
familiar and who's not.
Even if they can't tell you,
that's my mother or that's my
father or that's my brother,
their galvanic skin response
is a pretty good response.
Patients with orbitofrontal
lesions
are exactly the opposite.
When they're shown pictures of
family members and friends,
they have no more of a response
in the sweat glands,
in the autonomic nervous system,
than they do for
absolute strangers.
And you might intuitively
imagine that it's pretty easy
to lie and deceive your friends
and family, if they
don't mean to you anything more
than an absolute stranger.
No galvanic response
to emotional
versus neutral pictures.
And so these patients seem to
have this disconnection
between thought and emotion.
They know who the person is.
But they don't have an emotional
response of any kind
to that person.
And here's one clever experiment
that shows some of
the consequence of that.
So this is work from Damasio
and his colleagues.
So they took a couple
of these patients.
There's not that many of them.
And they put them into an
experiment where you could
pick from two decks.
One deck has a low immediate
reward, but
positive long-term rewards.
It's a little bit like studying
a lot, and hoping it
all pays off.
And another one is high
immediate rewards, but higher
long-term losses.
Like not studying has some
unpleasant consequences.
So two decks of cards.
And you don't know this, but you
just quickly discover that
Pile A, you get the occasional
$50, but you often lose $100.
But Pile B, you get the thrill
of the $100 loss, but you
often lose $1,000.
So they're kind of pitting
against each other, the thrill
of the $100 win, versus the
certain doom of the quick
thrill pile.
You get the quick thrill,
but it will doom you.
So what do typical people do?
After a little while, they
figure out well, Pile B is
pretty fun when I
get the $100.
But it beats me up a lot in the
long term, so they go for
Pile A.
Orbitofrontal patients don't.
They go for that one-time
thrill, over any long-term
consequences.
As interesting as that, if you
measure the galvanic skin
response, for control people,
typical people, when they go
for the risky pile, their heart
is pounding, their hands
are sweating.
And they go, I'm going to
walk on the wild side.
Back to the save file, mostly.
No galvanic skin response
for the patients with
orbitofrontal lesions.
Yeah?
AUDIENCE: Do people
get the lesions
after reaching adulthood?
PROFESSOR: So this
is interesting.
I'm going to come to
this in a moment.
Actually literally, absolutely
right now.
Same pattern for people who
have these injuries at 15
months or three months, as
happens in adulthood.
Now, we don't know if
that's everybody.
But these are patients who
came forth with problems.
So this is a little bit like,
we don't know if there are a
lot of people with damage there,
who are not doing this.
But these two patients who
they studied, had that.
And they got in lots
of trouble in
school, all the time.
They did all the things
you might imagine a
three-year-old, and for
the rest of us, like
Phineas Gage would do.
So that raises the question
about whether the kinds of
people who behave in this most
disturbing, psychopathic,
serial killer fashion have
either an injury or something
like that, that makes them
predisposed to being very
inhumane in the way they
think about people.
And just in case you, as careful
MIT scientists, worry
about well, maybe they're not
having a GSR that works at
all, what does that mean?
If these patients who had the
damage early in childhood just
get a loud tone, a big boat
horn, like ooh, there's a
galvanic skin response that
looks pretty good.
So it's not their autonomic
system won't respond to
emotionally provocative things,
like a big sound.
It just doesn't respond to
emotionally provocative things
like risk and people you
should care about.
And I'll just end in
this one minute.
So this is an area where a
guy, Kent Khiel, at the
University of New Mexico.
You can go look this up.
It's an amazing story.
He's very interested in these
brain differences in
psychopaths in prison.
Many are in prison because
they're scary people.
So you can't get them out to
do research very easily.
So he has a truck with
an MR scanner.
And he drives from penitentiary
to penitentiary
and does brain scanning
with these people.
And is getting on average,
some differences
in this brain region.
So I have a question for you,
just for one minute.
Do you think that should be
introduced in a court case for
a serial killer?
If he gets up there and shows
you brain pictures, should a
jury hear about that or should
they not hear about that, for
somebody who's done an
awful murder or an
awful string murders?
AUDIENCE: I'd say no.
PROFESSOR: Sorry.
You say no.
Because what?
AUDIENCE: I think that the risk
is too great that you
will have innocent
people be shown.
And the science is not fully
resolved yet in that respect.
There are also a lot of
salient factors and
environmental factors that
have been constrained by
genetics, and say, oh, if you
have this huge issue, this
condition of the brain, you're
automatically [INAUDIBLE].
PROFESSOR: OK.
Let me tell one sentence.
Yeah, go ahead.
AUDIENCE: You know the
correlation in one direction--
PROFESSOR: We don't know.
These are good points.
Let me just say, so here's where
we stand now, because
this will be your lives in
the future, in a lot
of different ways.
Where we stand now is, for the
first time ever, brain imaging
evidence was introduced in the
court case about a year ago of
a serial killer.
They were only allowed
to do it--
court cases like this go
through two phases.
You see these in TV
shows or movies.
There's the initial trial.
And if the person is found
guilty, there's a second phase
where they decide what the
appropriate penalty is.
The judge said they could only
be reported in the penalty
phase, when people were thinking
about what's the
right punishment for a person,
not before the conviction.
And they said they couldn't
show any color pictures of
brain stuff, because that would
over-influence the jurors.
And so you could only talk
about this stuff.
Because if you showed a brain
picture, sort of like you
said, it would look so
scientific that they were
afraid it overwhelm the
jurors' judgment.
So this is all coming up, about
what the brain maybe do
in your lifetimes.
Thanks.
