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PROFESSOR: Sometimes
psychologists like to talk
about two aspects of our mind,
the hot and the cool.
So the cool parts we've been
talking about recently,
thinking parts, like language,
thought, things related to
intelligence, problem solving,
the rational aspects of the
human mind.
And today we're going to focus
on maybe the hottest of the
hot, the emotions that we feel
and that color our lives in
terms of intensity and arousal
and what matters to us.
And so we'll talk a little bit
about, just very briefly about
a thumbnail history of the
study of emotion, the
scientific study of emotion,
ideas about how to define it,
a few models of emotion, how
emotion might work, some big
questions about things like is
emotion universal, does it
correlate to bodily feelings?
Why do we have emotion?
And then things about the
brain basis of emotions.
So we have a huge number of
words, by one count about 550
words, that describe the
feelings we have,
the emotions we have.
And there's a lot of overlap
conceptually among them, but
we have so many words because
we think that, we feel that
from our daily lives, the
feelings and emotions that we
have are such a big part of our
human existence, how we
relate to other people, how we
feel when we're by ourselves.
Emotions are just a big,
big part of how we
go about our lives.
And they're readily apparent
to us everywhere we look on
the faces of others.
Positive emotions, negative
emotions, fearful emotions,
you see them around
you all the time.
In psychology, a lot of ideas
about formulating the field go
back to William James, who
worked at Harvard, who
articulated in many ways, in
language that's still relevant
to this day, the basic ideas,
the basic things about being a
human that one wants to
understand out of a
psychology.
And he wrote about emotion this
way, "If you can conceive
of yourself suddenly stripped of
all the emotion with which
our world now inspires you, no
one portion of the universe
would have more important
characteristics beyond
another; and the whole character
of its things and
series of events would be
without significance,
character, expression, or
perspective." That what we
fear, what we desire, what
we enjoy, what we find
disgusting--
we'll talk a little bit about
disgust today-- that all those
things tell us what's important
and whether it's to
be avoided or approached,
enjoyed or loathed.
And so people have thought
about emotions.
You could pick a million
different cultural directions.
Here's a picture from
Greek philosophy.
But you could pick
practically every
culture around the world.
You can't be a human and
not think about the
feelings you have.
But kind of strikingly in terms
of research, for a very,
very long time compared to
language or thinking or many
topics, people didn't study
emotion because it seemed hard
to study scientifically.
And it's still harder to study
scientifically in many ways, I
think, than cognition.
But there's been tremendous
progress in bringing
scientific approaches to
understanding something about
emotions in you and I. And
like many things, it was
reinvigorated around the
Renaissance and the mystery of
Mona Lisa's smile.
And now there's entire journals
and conferences and
organizations of scientific
psychology
devoted to study emotion.
It's a big part of our lives.
You would think in the study of
the human mind and brain it
would be a big endeavor.
And it is now.
But that wouldn't have been
true even 20 years ago.
How might we define emotion
just to sort of have some
boundaries?
So we could say that emotions
are biologically-based
responses to situations
that are seen
as personally relevant.
They are shaped by learning and
usually involves changes
in peripheral physiology.
Your hands are trembling
or things like that.
Your heart is pounding.
Expressive behavior, the
intonation with which you
speak, the facial expression
that you
have or see in others.
And subjective experience.
The emotions you have go with
what you feel is going on
inside you.
Research has tried to
distinguish between moods and
emotions, and talk about moods
as diffuse, long-lasting
emotional states.
When you're in a funk or a
positive mood over days,
weeks, months, that's
not what we're going
to talk about today.
That's interesting and
important also.
We're going to talk about
emotions, which are very
punctate, immediate responses
to situations, to a specific
thing or a specific stress or
a specific element of your
environment, an immediate,
strong response.
And within that, one more
distinction has turned out to
be useful for thinking about
emotions between two
dimensions, arousal, or
you could call it
intensity, and valence.
Arousal means things that are
exciting, intense, if they're
high arousal, or calm
or lethargic
if they're low arousal.
Valence refers to whether it's
a positive thing that makes
you elated or contented,
negative sad or gloomy.
And you can already
see, for example,
take positive valence.
Elated is high arousal.
Contented, ah, that's
low arousal.
They're both positive, but
they're kind of different.
So is calm versus lethargic.
Being calm can be
sometimes good.
Feeling really slow, really
lethargic, also is low
arousal, but it's usually not
a desirable low arousal.
And so people think that they
can take basically these two
dimensions, valence and arousal,
and use it as a
useful way to say something
like calm is here.
It's a little bit positive
and it's low
on the arousal dimension.
Excited is up here.
It's a positive valence.
Different things, gloomy is
negative and it's fairly
intense feeling, as opposed
to merely lethargic.
These two dimensions can cover
a big sense of the life of
emotions that inhabit us.
And a huge question, and one
that's brutally hard to
satisfy in some deep scientific
way, of course, is
it restricted to humans?
So if you hang around pets
and animals in various
circumstances, you can't help
but feel they have emotions.
It's just very hard for us
to ask them to fill out
questionnaires telling
us their emotions.
Here's a chimp that has lost
its mother recently.
Here's a dog going out
for a good old night.
Here's an armadillo
going, whee!
It looks pretty aroused.
We don't know how much of this
in some cases is us reading
human feelings into their
expressions, how much of that
is them feeling the
same as we do.
There's a lot of sense,
obviously, that many species
have feelings as
well as humans.
We'll focus just on
humans today.
And the other thing that's
important is
they're shaped by learning.
What that means is many
different things, but for
example, they can vary from
one culture to another in
certain ways.
And here's one example of a
movie that's bringing tears to
everybody's eyes, except
this person who
finds it utterly hilarious.
If you work in emotion
research, I can
tell you you get that.
I worked a little bit on that.
You show some really horrible
pictures to everybody.
They go, oh, horrible,
horrible, horrible.
And somebody else
starts laughing.
It's like horror movies.
Have you've been around horror
movies where some people are
really scared out of their seats
and very worried about
the characters and other
people think
it's all pretty funny?
So that's your prospective.
It's not an automatic response
to many situations.
So how have people thought about
the emotion you feel
when a bear jumps out of your
closet unexpectedly?
Here's the logical one.
Common sense.
Bear is scary.
You feel fearful.
That's your subjective
experience.
And your body starts to
do things like your
heart starts to pump.
Your sweat glands start
to sweat, because
you go, this is dangerous.
This is scary.
Here comes my body.
That would be the
intuitive one.
My heart is pounding because
I feel afraid.
Interestingly, you can reverse
the order and find some things
that are better explained
that way.
It's sometimes nice, sometimes
people will say, oh my gosh.
Everything in psychology
is so obvious.
For some reason, they always
say, my grandmother
would have known it.
I don't know why they
pick that example.
Show us something that science
only can tell you.
So here's a very clever reversal
from William James
and also Lange.
They reversed it.
They said that first comes the
bodily response to the
situation and second comes your
mind interpreting your
body's primary response.
The exact opposite order of
why we feel as we do.
"We feel sorry because we cry,
angry because we strike,
afraid because we tremble, and
not that we strike, cry, or
tremble because we are sorry,
angry, or fearful." He sees
the exact opposite.
Here it says first comes an
emotion that's shaking your
body in some way, and then comes
to your mind saying,
aha, I'm afraid--
pretty fast--
or I'm happy or whatever.
Here's some examples, because
you could think, OK, yes, you
can cleverly reverse them.
But is there any science to
suggest that in some cases
that relationship
does reverse?
So here's what people did.
And I'll show you a
picture for this.
They said, how can peripheral
bodily events, things on sort
of the edge of our bodies,
influence the
emotions we feel inside?
So they would have people do
things like hold a pencil
tightly between their
teeth and--
look at that pencil.
They're not told to smile.
They're just told to keep
that pencil there.
And what does that look like?
A smile, right?
OK.
You've tricked the person's
face into smiling.
And they don't even know
that, necessarily.
They're thinking, this is a
weird psychology experiment
about how long can you hold a
pencil in your mouth, although
they're going to know something
more in a moment.
Or between the lips,
hold that pencil.
Now, does this person
look happy?
No.
A little bit not happy, right?
OK.
And then you have them watch a
funny movie that most people
find funny.
And they rate how much
they like it.
And the person who had this one
rates it as more enjoyable
than the person holding a pencil
this way, as if already
having the muscles in your face
moved into a position
that typically signals happiness
or laughter makes
you feel happy inside and the
funny movie is even funnier.
Being in a somewhat neutral to
negative position makes that
same funny movie seem
less funny.
You're interpreting where your
muscles are that normally go
with one emotion or another,
and that's driving your
internal final emotion about how
you feel about the movie.
Was there a question?
AUDIENCE: Could it require more
concentration, or patience?
PROFESSOR: Does one require
more concentration?
That's an excellent question,
because we always like to say,
oh, it's this thing.
What if this is a harder
thing like that?
And so when one have to
hope-- and I have to
admit I don't know--
that they've controlled for
things like that in some way.
If you read the research paper,
you'd want to be concerned.
That's an excellent question.
If this is just harder work than
maybe you're paying less
attention to the movie and just
hanging onto that pencil.
I don't know.
And I have to hope they did
a good job on this.
That's an excellent question.
And here's other ones, again,
where they're trying to get
the face to go smiley
or go frowny.
And then they just ask them,
how do you feel?
And this person will rate
themselves as feeling happier
than this person as they answer
on a piece of paper in
front of them.
Again, they're trying to say, if
I can move your peripheral
facial expressions into--
your muscles into expressions,
the feelings will follow from
the expressions.
You can also do something else,
which is you can tell
people-- so Paul Ekman, his name
will come up a lot today.
He's done a fantastic amount of
the key research on this,
making emotions into a research
topic in many ways.
What he developed is a way that
he said, I'm going to
describe objectively which
muscles are in which position
for each of six fundamental
emotional expressions.
We'll come back to those.
So he would tell a person, raise
your eyebrows and pull
them together.
Raise your upper eyelids.
Now stretch your lips
horizontally back
towards your ears.
So what he's giving this person,
step by step, is
directions that move the muscles
into an expression of
fear, by the time you
end up there.
The participant usually doesn't
know that, because
it's so weird.
You're moving your mouth.
You're moving--
it's just so weird.
But then they can do these
kinds of experiments.
And these people will report a
fearful movie as being more
fearful than somebody who just
gets to sit there or whose
muscles are moved into
a happy position.
So all of a sudden you've got
all these peripheral things
being interpreted by our mind
as a signal for what emotion
you have, or enhancing
it anyway.
And then because any strong
theory usually turns out to be
not nearly complicated enough,
you get the wishy-washy middle
that probably covers more of
the truth, which is both
things are going on.
Both you're having a subjective
cognitive
interpretation of your
environment and a bodily
response, maybe more
in parallel than
one driving the other.
So again, how can peripheral
bodily
events influence emotions?
One idea that's floated around,
and probably true, is
that the perception or
thought, your mental
interpretation of your emotion
tells you the type of emotion.
so if a bear jumps out, you
can say, OK, I know
something's pretty intense.
And I can tell you right
away it's bad.
But if something wonderful
jumps out of your closet
unexpectedly, then you
go, oh my gosh.
I can't believe Lindsay Lohan
is visiting me and I didn't
even know it.
Then if that is considered
a good visit, that would
influence again, the
interpretation, but the
intensity might come from
the bodily parts.
How intense it is might
be signaled from that.
So here's a couple of ways
that people explore this.
Here's a study from years ago
from Schacter, where he
injected people with
adrenaline--
adrenaline is the neurohormone
that goes with high arousal,
it raises your heart rate--
or a placebo.
So he's directly taking the
chemical that we normally
produce under higher
arousal conditions.
And the first question you might
ask is, and you might be
curious about, if somebody gave
you a shot of adrenaline,
what would happen?
Would you like jump out
of your seat and run
laps around the room?
What would you do?
And surprisingly, all by
itself, not very much.
People said they feel a bit
jittery, like if you've had
maybe a little too much
coffee or Red Bull--
is that the current?--
that little jittery feeling.
But they're not like jumping
up and do jumping jacks and
one-armed push-ups and
stuff like that.
Now, having had the placebo or
the adrenaline injected into
you, and you don't know
that, they show you an
emotion-eliciting--
they'll show you a movie,
like a horror movie.
And the people who had the
adrenaline will report more
fear when they see the horror
movie, more anger when they
get insulted.
That's a fun experiment
when you insult them.
I'm sure the IRB, you have
to be pretty careful.
More laughter for a comedy.
Adrenaline seemed to amplify the
intensity of the emotion.
But the emotion was driven
by the situation.
Does that make sense?
OK?
But here's something quite
interesting about humans,
which is that if you told
them, we've given you
adrenaline and it usually
amplifies stuff, then it
disappeared.
Once the person knew that, they
could discount that in
their mind.
So it's not like adrenaline is
your master, and that I must
have twice as big a response.
Once you knew that was in the
picture, then the ratings went
back to placebo.
It's not that biology
is destiny.
But under normal circumstances,
it seems like
the adrenaline accentuates
the intensity.
So that would go with the
possibility that peripheral
stuff drives the intensity,
peripherally injected
adrenaline, and our mind's
interpretation drives the content.
Here's a sort of fun, slightly
sexist experiment that in the
end, I think, explains the
following phenomenon.
When you see famous movie stars
go into a movie set, on
set, or whatever they call it,
you incredibly often hear
about romances occurring between
the leads, right?
And there's debates about what
this is just the press agent
selling their movie
or whatever.
But you hear that all
the time, right?
OK.
So I'm going to tell you
why that happens
when it really happens.
I can't really tell you that.
But I can tell you an
experiment that
might touch on that.
So here's the experiment.
This was done by Dutton
and Aron in
North Vancouver, Canada.
And they did the experiment in
an area where there were two
bridges not right next to each
other, pretty near each other.
One was a flimsy suspension
bridge, five feet wide,
swaying and wobbling 320
feet over jagged
boulders and river rapids.
So you have to imagine
Indiana Jones, OK?
And you come to this
bridge and you're
going, I don't know.
OK.
The other one, upstream, same
river, same Canadian district.
There's a steady, low,
broad bridge.
No problem at all.
You could drive your car
over that, no problem.
Two bridges over the
same waters, one
seeming scary, one not.
Then what they did is in the
middle of each bridge they
placed an attractive, in this
case female, confederate.
Maybe somebody's done the
reverse gender experiment.
I don't know.
Anyway, as men walk across the
bridge, they ask them to fill
out a questionnaire, some
boring questionnaire.
And they casually mentioned that
if that person, as they
finish the questionnaire, has
more questions, he can call
the woman providing the
questionnaire at home.
And she provides him
her home number.
And the measure that they have
is how many phone calls go
from the male subjects to the
female experimenter at home.
And they're betting that it's
not really scientific
curiosity that's driving a
lot of the phone calling.
But here's what they
actually find.
More males will call that female
at home if they were on
the dangerous bridge than
on the safe bridge.
That's the actual finding.
And the interpretation is this,
the dangerous bridge,
because of the true feeling of
danger, produces high arousal,
increased adrenalin.
And that's misinterpreted, if
you want to call it that, by
the male because he thinks now
he's super-attracted to that
woman because of the
swaying bridge.
Another reason to take somebody
you want to win over,
whatever the gender situation
is, a really scary roller
coaster ride is highly
recommended together with that
warm beverage, as long as it
doesn't spill on them.
I'm making you too powerful
to control people.
Again, the arousal of the bridge
has been misinterpreted
by that person as an intense
attraction to that woman.
And you could imagine making
movies are probably high
arousal exciting situations,
and that would promote
romantic relations and high
intense situations that might
not otherwise occur.
Yes?
AUDIENCE: [INAUDIBLE]?
They had to randomly assign
them to one bridge or the
other, you would hope.
I can tell you there's been a
bunch of other experiments
sort of like this.
This is the most what you could
call ecological, silly,
or sexist, you could figure.
But they all go with this idea
that if you're in a high
arousal situation, you sort of
move over that arousal into
whatever it is you're
encoding.
Does that make sense?
And in this case, because you're
creating an interaction
between a man and woman, it's
promoting this probability of
a sense of romance
in the male.
Is that OK?
But it could be any situation.
The arousal will make it-- if
it's something, it can make
you feel worse about it.
AUDIENCE: [INAUDIBLE]?
PROFESSOR: Ah.
Totally excellent question.
You're asking awesome
questions.
I have to assume-- and I should
know this, but I don't--
that they weren't.
Yes, because if you had males
self-selecting, you had some
males running to the danger
bridge, drawn to danger, and
others saying, oh, please give
me a safe road, is that the
real difference.
So you have to presume
they did something to
control that, yes.
Excellent question.
The current view is something
like that there's two factors,
that there's both.
A bodily response that happens
pretty fast, pretty
automatically, pretty
unconsciously.
There's a lot of
interpretation.
And the combination of that
bodily response and an
interpretation leads you finally
to the subjective
experience you have, and
probably works differently for
different emotions.
And things are complicated.
But we're pretty far from this
first guess in terms of the
fact that peripheral things can
have very powerful effects
on how you interpret situations,
the intensity of
your interpretations.
And the intensity itself can
change the behaviors that
follows the situation.
Three questions in the field
are, are emotions universal?
Are they in you from
when you're born?
Are they the same for people
around the world?
Do they have unique
physiological signatures?
Could we define--
if we knew your heart rate, if
we knew your pulse and so on,
could we know what emotional
state you're in.
And then speculations as to why
we have emotions at all.
What's the use of
having emotions?
Brilliant as he is in so many
ways, in many ways this
dialogue began in modern times
with Charles Darwin, who
noticed that animals had very
striking facial expressions,
as we saw before.
And that made him think about
the evolution of facial
expressions.
This is one of his drawings
of a cat.
Here are infants having early
displays of emotions, joy,
disgust, surprise, sadness,
anger, fear.
So people have been very
impressed that very early on
infants are having the full
array of expressions.
Of course, they might
see them.
From moments from their birth
they have people around them.
But it's very early, that's
almost for sure.
A really interesting line of
research-- and I'll show you
an example-- has been looking
at emotional expressions,
emotional facial expressions, in
people who are born deaf or
born blind, so they never
hear intonation.
They never see a facial
expression.
They can't learn it from
their environments.
So they're sort of a natural
window into is this inborn in
us, or do we learn it from
people around us?
Here's an experiment where they
took spontaneous facial
expressions of emotion in
athletes from both the
Olympics and the Paralympics.
And they looked especially at
congenitally blind people,
born blind, never saw a face,
and sighted athletes.
And they looked at the
expressions after winning or
losing an Olympic-level match.
Before I show you this, you
may know the story.
What happens after
an Olympic event?
Somebody wins and where
do they go?
You know this podium thing?
The gold medal winners up here,
and the silvers here and
the bronzes here.
And they've also done
studies--this
is just a side note--
saying, who looks the happiest
in those pictures?
AUDIENCE: Bronze.
PROFESSOR: The bronze
medal winner.
Who looks the saddest
in those pictures?
AUDIENCE: Silver.
PROFESSOR: The silver, right?
Because the bronze medal
winner's going, thank goodness
I came in third place.
I'm on the podium.
I have an Olympic medal.
If I'm in fourth place, fourth
through infinity gets the same
Olympic medal, right?
The silver medalist, what's
he or she thinking?
On average.
Man, if I had just one more
fraction of a millisecond, I
could be the gold medalist.
It's kind of an interesting
thing of when we consider
things satisfactory or not.
But now let's turn back
to this question.
Here's two people who just lost
Olympic medal matches.
And your question is which is a
sighted person and which is
a blind person?
And to the extent it's hard to
be certain, that would be a
big suggestion that these
expressions are inborn in us,
because a person who's never
seen a sad expression still
has a sad expression.
And the answer is, that's the
blind athlete and that's the
sighted athlete.
So it's pretty convincing, I
think, that we're born with
this set of expressions as a
core entity of being human.
Even though we're born with
that, we live in different
cultures, very different
cultures around the world, and
even within countries and
across countries.
So how universal are these
sorts of things?
And there's lots of evidence
of a degree of influence of
cultures around this
core universality.
So does a smile mean friendship
to everyone?
And again, Ekman and Izard made
a big study in which they
argued that as far as they can
tell in looking around at
facial expressions, there's
six basic emotional
expressions that signal
feelings, happiness, sadness,
fear, anger, surprise,
or disgust.
These are all people who are
trained to try to make the
perfect expression
of those things.
They look kind of weird
by themselves, right?
They look kind of weird.
You don't see a neutral
one here.
Maybe we'll see a neutral
one later.
Neutral is kind of weird,
because you
go, well, it's neutral.
But I can tell you, a totally
neutral face looking at you
can be kind of creepy.
Because if you interact with
somebody and they have no
expression at all, it's
a little disturbing.
But these are ones are pretty
universally recognized, but
not completely.
Let's take Westerners,
people from the
United States or Europe.
We're not perfect in that.
Even with these posed pictures,
this is how often
people came up with the
correct labels.
Pretty often, not perfect.
There's a lot of mystery
at the edges of this.
But here's how people came up
from non-Western cultures for
the same Western faces.
Well above chance, but not the
same as Westerners looking at
Western expressions.
And it would reverse if
Westerners had to look at
non-Western expressions.
So there's definitely a degree
of cultural influences on the
recognition of these expressions
as well.
It's partly innate and
universal, and there's a
cultural overlay as well.
This is a joke.
"Shoot!
You've got not only the wrong
planet, but you've got the
wrong solar system.
I mean, a wrong planet
I can understand.
But a wrong solar system--" And
you can tell with just a
little information that this
is a sheepish smile of
embarrassment.
And this is a little bit of
the body expression of a
little bit of irksomeness.
Irked.
But here's an isolated
pre-literate
tribe in New Guinea.
And that smile looks like the
smile of any kid you ever saw.
That's sadness, the sadness
of any kid you every saw.
That's a little bit
of a disgust.
And some people have built up
a model, something like
there's things in the
environment that happen that
drive some sort of facial
affect program.
Your muscles in your face move
to express 6 or so different
kinds of feelings.
Cultural rules about what should
you show, what should
you not show in different
cultures.
Some face's expressions are more
appreciated than others.
And finally, all of that
moves into the facial
expression you make.
So now the second question we
have, we think to a first
approximation emotions, at least
as far as we can tell,
are pretty universal but there's
cultural and learned
pieces as well.
Do emotions have unique
physiological signatures?
Can we tell from your
physiology what you're feeling?
And there was a lot of hope that
this would work, because
intuitively emotions differ
from one another.
Our body feels different
as we go from
one emotion to another.
And we use language words like
"she got hot and bothered."
"You make my blood boil." "He's
just letting off steam."
Different physiologies go
with different feelings.
And so people hoped they could
make decision trees like this.
Let's measure your heart
rate, high or low.
Well, if it's high, then we
get your skin temperature.
And then we can tell if you're
angry or fear or sad.
That you could make a decision
tree by looking at peripheral
measures of physiology.
But it never worked.
It's never been strongly
discriminating.
People have not been able
to have a physiological
fingerprint for the emotion
that you feel that's
reasonably accurate.
Yes?
AUDIENCE: So why are they
[INAUDIBLE] as something that
could go in that tree,
for instance?
Could they measure chemical
concentrations in places?
PROFESSOR: It's possible, yes.
Here's a very good question.
Here they're measuring
peripheral physiology or
autonomic systems, skin
temperature, heart rate.
Could there be other things
like chemicals, right?
So I'd say yes, but we just
don't know them well enough.
Or could you have brain measures
that ultimately would
be sophisticated enough?
I can tell you that brain
measures are not that
good at that now.
But could they be someday?
Yes.
So yes, it's the specific
measures that we have.
A really deep question will be
at some level when you're
fearful and I'm fearful, how
identical will those be,
depending on our cultural
background, depending on
situations we've experienced?
We can both agree we're scared
of something, but it could be
pretty different.
So it's a really
deep question.
In the end, how close are these
things from one person
to another?
Now, at least at speculative
is why we have emotions.
And sometimes people think
it's intrapersonal
functions within us.
We're organizing ourselves--
what's our basic feeling?
Are we basically happy or sad
about something or fearful of
something?--
so that we use that feeling as
a source of information to
sort of pull ourselves
to say, this is
basically where I'm at.
It's a source of information
for me.
And it can tell me what behavior
makes sense to do in
this context.
And then from one person to
another, interpersonally.
What does that person feel?
What am I signalling
to that person?
So here's an experiment.
And I'll show you just a brief
YouTube video on this, because
I think it's really cute.
But it's almost a life and death
experiment, although no
infant was harmed in the making
of this experiment.
So what they do is, this
is a visual cliff.
An infant is put on this,
a very tiny baby.
Here it's hard Plexiglas.
There is no danger
to the baby.
But there is a drop here
and a drop here.
Now, as the baby approaches
this, they're not used to the
idea of Plexiglas.
Even you and I would be pretty
worried about that if it was
on a larger scale.
We'd want to be pretty sure
about the strength of the
Plexiglas But to the infant's
eyes, they're approaching what
they call a visual cliff.
On the other side--
I'll show the film
in a moment--
is a mother.
And the mother can either be
showing a positive expression
or a negative expression.
And look what happens to the
infants in this perilous
situation where they see a drop
that's a big, and how
much they trust their mother's
expression to know what to do.
So if the mother is looking
happy, like it's OK.
This is going to be great.
We're having a lot of fun.
3/4 of the time the infant
goes for it.
If the mother looks
scary, never.
They're making kind of a
dangerous decision entirely on
the facial expression of the
mother and their trust that
the mother knows the right thing
to do and is giving them
the right advice.
Sometimes everything in
psychology can just seem like,
oh, it's just another thing.
But facial expressions are an
unbelievable powerful way that
we communicate with
one another.
Here's an extremely clever
experiment from Adam Anderson,
who happened to be a
postdoctoral fellow in my lab,
but he did this completely
independently.
Here's the question.
So we have some different
expressions.
And you could say, well, are
they completely random as to
what the actual expression is?
We haven't even asked this.
Why does a smile go one way and
a frown go the other way?
Does it mean anything or are
they just arbitrary signals of
different emotions that have
evolved over time?
And he's almost the first
person I know to
even ask this question.
And he looked at two emotions
that we'll come back to in
just a little bit, fear,
and disgust.
And he thought, well, look, it's
kind of interesting what
fear and disgust do.
For example, fear, your eyes
get bigger, disgust--
think about something
really stinky--
you close your eyes.
You sort of scrunch
up your nose.
Look at this.
And he looked at and measured
how airflow patterns and
different things happen when you
go into those expressions,
non-arbitrary properties
of an expression.
And then he did psychological
expressions.
He got people to get into
these expressions.
And he found that if they were
in a fearful expression, that
they would feel like they had a
wider field of view, and if
it's disgust, a smaller.
Now think about this
for a moment.
When it's fearful, do you want
to feel like you know what's
going on around you?
Or do you want to sit back
and think about stuff?
Or do you want to
say like, uh-oh.
Where do I run?
What's going on?
When you go into some disgusting
situation, do you
want to really look
around a lot?
Or are you kind of happy to
find some way out of it?
Same thing with your nose.
Here's the air velocity that's
passing through your nose when
you're fearful and when
you're disgusted.
Now you don't even
think about that.
Who's thinking, I'm controlling
my air velocity?
But why do you think you might
want to really sample your
environment when you feel
danger, visually and in an
olfactory way?
Why do you think you might
want to sample?
Well, you want to know
what's going on.
You want the information
as fast as possible.
Do I run?
Do I duck?
What do I do?
Do I fight, flee?
What do I do?
I have moments to decide,
because I'm in danger.
If you're in a disgust
situation, are you interested,
typically, in exploring the
olfactory environment in as
much detail as you can?
Usually not.
So it's kind of interesting.
The very first time --
I know, it's very clever --
asked where do these expressions
come from?
Well, maybe they tend, to a
certain extent, to exaggerate
or diminish forms of sensory
input that are relevant for
the emotion.
So for the last little bit I'm
going to talk about for a
little while what we know
about the brain
basis of some emotions.
We already talked about the idea
that the amygdala plays a
special role in fear.
And I'll show you a couple
different ways in
which that's true.
This is just sitting in front of
the hippocampus, one on the
left, one on the right,
the core elements
of your limbic system.
Here it is viewed from the
side, the amygdala.
Here's the actual amygdala
from a post-mortem brain.
And there's another whole level
of analysis that animal
researchers do that we can't
touch today, which is the
amygdala itself is made out of
bundles of neurons called
nuclei, very distinct ones that
have different roles,
different inputs, different
outputs.
And in animal research, where
you can selectively influence
one or the other, you can see
they have quite different
specific roles.
In humans we don't have that
precision of control, so we
sort of have some clump average
statements about the amygdala.
But really we're mixing together
a few functions.
So you already saw this picture,
that animals, mice or
rats, that have an amygdala
removed lose the fear they
ought to have of a cat.
In primate studies, they found
that if they have amygdala
lesions, the loss of threat
appreciation impairs social
fitness, that animals that don't
know what they ought to
be afraid of get into
big trouble.
They lose their position in
dominance hierarchies.
You may know primate groups
tend to have dominance
hierarchies, a sort of
alpha male and so on.
They slide down that.
If they lesion the dominant
male, the alpha male, the male
who wins all the fights and
controls the group, that
animal will fall down the
hierarchy and become
subordinate.
And in the wild, they've shown
that if they do lesions and
return the animal to the social
situation, they get
rejected by the other animals,
because the other animals feel
there's something weird
about the animals.
And they're often isolated and
they get to early death,
because the other animals
are not helping them
or supporting them.
So very important for learning
what's dangerous.
Here's an experiment with rhesus
monkeys lesioned at two
weeks as infants, returned to
their mothers, and tested at
eight weeks.
And here's an example of
something, this is if you show
an animal a novel object.
And this is how often
they respond to it.
Young animals will often not
explore it, because they go,
well, I don't know.
That could be dangerous.
They're waiting for their
mother's expression.
Here's the other animals with
the amygdala lesions.
They'll explore it.
In a sense, they're fearless.
But that's probably not an ideal
thing to do when you're
an infant exploring the world.
Or they'll put food only or
food next to a play snake.
Snakes are dangerous
for monkeys.
They usually don't want to
figure out at this age is it a
play snake or a real snake?
They just say, I don't really
need to eat that.
So everybody likes the food.
Put the snake next to it, and
the control animals go, no, I
don't think so, basically.
The amygdala ones, what's
for dinner?
And the answer is, if it's a
real snake, you're for dinner.
So they lose the fear of things
they ought to have fear
of, they lose fear of unknown
things, fear of things they
ought to be afraid of.
So the amygdala plays this
really important role.
Fear sometimes is maybe the
best understood emotion in
terms of brain processes, and
maybe the most studied, partly
because we've had some success
in understanding what's going
on and partly because fear is
maybe the emotion that most
people think is closer
to survival.
You fear what kills you.
You fear what pains you.
That's a very powerful emotion
for survival and safety.
And you can do fear
conditioning.
We talked about conditioning
before in all species, from
humans to primates, other
mammals, fruit flies.
All of them have, to a first
approximation, similar fear
conditioning.
It's as if you're alive, you
have to fear things that are
scary and dangerous.
So people have done fear
conditioning experiments.
And now you know
this very well.
You might hear a tone that's
not scary at first.
If you put it with something
that you don't like, like a
foot shock, you get fearful
to the tone.
And what people have discovered
kind of remarkably
is that you can make lesions in
many parts of the brain and
you don't affect that learned
fearfulness to the tone.
But if you make a damage in the
part of the amygdala, you
abolish that learning.
These animals fail to learn the
signal of something that
is coming up to be painful
and dangerous.
And you can even make large
lesions in the cortex.
That doesn't affect anything.
And these animals with the
amygdala lesions, they have an
intact unconditioned response.
When they get the shock, they
jump like the other animals.
They don't like it.
It's not that they
can't feel pain.
They can't learn that the tone
predicts the painful stimulus.
They can't learn the warning
signal of danger.
There's very few patients with
amygdala injuries only.
But there's a few.
So here's a patient, SM, who's
been studied by Damasio and
his colleagues.
This is where the amygdala
ought to be.
It's a developmental disorder
where this is calcified very
early in development.
It's not an adult lesion.
But it seems to be fairly
amygdala-specific.
And people have done
a couple of
experiments with these patients.
And it's sort of guided our
understanding of what the
amygdala does in you and I.
Here's one example where they
did conditioning.
Again, in this case they
didn't use shocks.
They used a super-loud
boat horn that's
pretty noxious to people.
People don't like it.
And they preceded that with
something gentle that warned
you it was coming.
Here's the initial response.
And here's the important
thing.
With humans, of course
you can--
well, let me just say they
managed a skin response, a
galvanic skin response
to the bad tones.
So here's the conditioned
stimulus, the response to the
boat horns in the conditioning,
what predicts
the boat horns.
Here's the response
to the baseline.
And here's the performance of
patients with amnesia who have
the amygdala--
controls, I'm sorry, who both
can tell you they're
responding selectively to the
scariest tones and also
remember perfectly well.
At the end of the testing
session, you go, what went on?
And they say, oh yes.
Well, when I got one signal I
got a horrible boat horn.
And when I heard the other
signal, I got nothing.
It's easy.
You do that for half an hour.
You get one visual signal that
means boat horn coming up, one
visual signal, nothing
coming up.
If you have patients who have
amygdala lesions, that
galvanic skin response doesn't
happen, even though they tell
you perfectly well afterwards
what happened.
So they know just like everybody
else that they got a
certain signal that went with
a noxious boat horn.
But their body is not learning
that association.
If a patient has hippocampal
damage, their body learns that
association, but they don't
remember it afterwards
consciously.
So you can separate out two
kinds of learning, a
hippocampal-dependent learning
of the facts of the session,
and an amygdala-dependent
learning, which is a bodily
response to learning that
something is dangerous and
unpleasant.
Now, we often learn things like
the visual cliff without
having to have a boat horn
and practice, right?
If somebody tells you that
something is dangerous, or you
figure out that something is
dangerous, you don't have to
go through a terrible experience
to pretty much
decide you're not
going to do it.
So here's an experiment that was
aimed at showing you that.
What people were shown-- there's
a funny human subjects
wrinkle to this I'll
just tell you.
This occurred at Yale,
where they had a
blue square came on.
That means safe.
You can just relax.
Nothing bad's going to happen.
But when the yellow square
comes on, get ready.
You might get a somewhat
unpleasant shock.
But they never give
them a shock.
So you're not learning
that way.
You just factually learn that
something is safe and
something is dangerous.
And here is the amygdala
response to the scary one, to
a neutral situation, and
to the one where you
know, ah, I'm safe.
So you never got the shock.
You never got the shock.
You were just told
about the shock.
You didn't have to get
it, but you're human.
You can figure this out.
And your amygdala is going, you
know, I can just figure
out that's dangerous.
That's baseline.
And that's the absence of
danger, positive safety.
The Yale IRB, hilariously I
think, said, oh, but you're
deceiving the people, because
you tell them they might get a
shock and they never
got a shock.
So you have to give them one
shock at the end of the
experiment.
So dutifully, the experimenters
gave them one
shock after the experiment was
over so they were honest.
Because during the experiment,
as they measured the brain
activation in the amygdala
responding to the threat of
pain without any pain
being associated--
we're smart.
We can learn something is
dangerous just by thinking it
through, and it engages the same
part of the brain that
learns by actual painful
experience.
Now how about memory?
So here's the way this
study was done.
People viewed a slide
story with an
emotional middle section.
So an example would be this,
parents are home having
breakfast with a kid.
Parents go to work.
Kid walks to school, kind of
tragically, but these are all
slides, again, nobody
was injured,
child is hit by a car.
Something high arousing
happens in the
middle of the story.
Everybody runs to
the hospital.
The kid is OK.
When people ask a week later or
something like that, a week
later, tell me about the stories
I told you last week.
There's a number of stories.
People have best memory for
the part where something
highly arousing happened, like
the child was hit by a car.
That makes sense, right?
Kid having breakfast, huh.
Kid OK, huh.
Car accident with a kid,
you're aroused and you
remember that better.
Emotion is amplifying memory.
The patients with the amygdala
lesions don't have that memory
bump based on emotion.
The emotion is not enhancing
their memory.
And you can imagine that there's
a pretty good reason
for emotions to enhance
memory, right?
If something is fearful,
delightful, horribly
disgusting, those are all good
reasons to remember.
Let's do that again,
if it's great.
Let's avoid that, if
it's terrible.
It's a good idea for emotions
to drive memory formation.
And in your brain and mine, it
appears the amygdala has this
role of transforming emotions
into memories.
Now we also talked about
six facial expressions.
And I showed you this before.
The same patients have trouble
in recognizing fearful facial
expressions.
So the amygdala in so many
different ways, learning,
memory, perception of faces,
seems to play this
huge role in fear.
And kind of interesting way,
because you might have the
intuition--
and a lot of this came
from Freud--
that a lot of emotions are
happening kind of under our
conscious awareness.
We almost discover them after,
like why am I angry with this
person, or why am I so happy?
We have to think it
through, almost.
If you show subliminal fearful
faces versus happy faces,
subliminally presented so people
can't tell you what the
facial expression was, still
they turn on the amygdala.
So unconscious perception
of a fearful
face engages the amygdala.
You don't have to go through
consciousness.
Cortical blindness.
We talked about that earlier
in the course, where you're
blind in one visual field.
And yet individual patients, a
couple of them with cortical
blindness, if they were shown
a fearful stimulus in the
cortically blind field, still
turn on, in the cortically
blind field, the amygdala for a
fearful face versus a happy
face, which indicates that a
non-conscious, subcortical
pathway that doesn't intersect
with conscious thought or
cortex, is sending information
from your eyes to your
amygdala, a different pathway.
And people have speculated that
maybe again because fear
is survival and danger, we might
have a super-highway of
information that sends
dangerous information
immediately to our amygdala.
It doesn't wait for you to think
a lot, so to speak, in
your cortex.
Boom.
Danger, danger, danger, even
before you process the rest of
the situation.
So we talked about fear and the
threat in the amygdala.
I'll just say a word
about disgust.
People think there's many
reasons things we can be
disgusted at or about, but
that maybe in terms of
evolution, it might have been
a pretty good signal for
contaminated food, food that
makes you sick, things to
avoid that make you sick.
And it turns out another part of
the brain called the insula
is pretty important for that.
So here's the amygdala
left and right.
Here's the insula that
you have, left and
right, outlined in purple.
And again, just like with the
amygdala, patients with
lesions of the insula don't
recognize facial expressions.
And imaging wise, if you see a
disgusted face, that turns on
that part of the
brain as well.
So those are the best understood
brain pieces of
emotion by far.
So now those are patient things,
so let me turn for a
moment, lastly to a few imaging
studies of typical
people and some topics
on emotion.
So here's some terrible
pictures from 9/11.
"The horror of the moment"--
and we always
imagine we'll remember--
and we've already talked a
little bit about this in
flashbulb memories--
emotionally things correctly
for a long time.
"'The horrors of that moment,'
the King went on, 'I shall
never forget.'" This
is Lewis Carroll,
Through the Looking Glass.
"'You will though,' the Queen
said, 'if you don't make a
memorandum of it.'"
And now you know that Lewis
Carroll was talking about the
amygdala, right?
You didn't know that before,
but you know that now.
Because if the amygdala isn't
there, the emotional intensity
doesn't make the memory more
permanent or more powerful.
So Larry Cahill at UC Irvine did
the first brain study on
this topic.
And what he did is he showed
students while they were
getting PET scanning, Positron
Emission Tomography, short
films that were either
powerfully
emotional or neutral.
And then he brought them
back three weeks later.
And here's what he found.
The more activation there
was in the amygdala--
each square here is a
different person--
the more they remembered
the emotional stuff.
But it didn't matter
for neutral things.
So the amygdala seems
unimportant for neutral
information, but the more it
was engaged, the more they
remembered emotional
information.
So this is sort of evidence in
the typical human mind of a
relationship between
the amygdala
and emotional memories.
So here's an experiment actually
that we did at
Stanford, where we showed
people stimuli that were
either neutral, somewhat
negative-- and I'm going to
show you something that's
very negative.
If you don't want to look, close
your eyes for a moment.
Close your eyes.
Here we go.
Very negative.
OK.
Sorry.
It turns out if we don't show
you something that negative,
it's hard to get your
brain pumped up.
It doesn't have to be
that sad, but it has
to be pretty intense.
So we show you things
like this.
And we record your brain
response for each of those.
And here's what we do.
We ask you to tell us
how bad is this?
So the baby picture was
bad for most people.
We wait three weeks, pretty long
time, and then we test
your memory for the scenes
from before.
We test your memory three weeks
later, pretty long time.
And here's what we see.
Two things.
In the left amygdala in this
study, here's what you rated
as terrible, pretty bad,
somewhat bad, and neutral.
So the amygdala is responding
to your subjective sense of
terribleness.
Now, we were really looking
at arousal and negativity.
We didn't look at
positive ones.
I can tell you in
other studies--
and here's a trick
in research.
I'm going to tell you now--
I only have a couple more
slides, but I'm going to tell
you a little bit about insider
things on imaging, just so you
understand imaging as as human
and fallible a form of
research as anything, which
you might suspect anyway.
So we show these things.
And we got these responses.
So that's going with your
subjective sense of
how bad films are.
And then we tested people's
memory, what we also found was
that memory was best
when we got the
biggest amygdala response.
So that's just like
you heard before.
So that all seemed find and
lined up with a prior result.
But here was the slight surprise
in the thing that
followed and that still gets
cited fairly often.
It's the research that I've
been affiliated with that
still gets cited most often in
newspapers and magazines.
Anyway, so this was a study
that you saw before.
And the thing I didn't emphasize
to you was that this
was in the right amygdala,
in the right hemisphere.
It doesn't really matter.
It just happened to be there.
Our study at Stanford was
in the left hemisphere.
This is where we were getting
the emotion memory responses.
And so we were very
deep scientists.
And we said, what could
be going on?
Why is Larry Cahill at
UC Irvine getting
it in the left amygdala?
The more active it is, the
more you would remember
emotional information.
And why is he getting it in the
right amygdala and we're
getting it in the left?
So we took a piece of paper
and we wrote down the
different things that
people had found.
Oh.
The story I was going
to tell you is about
Stephan Hamann's study.
So Stephan Hamann at Emory did
a study where he said, OK.
All this amygdala response to
negative things, does it also
respond to positive things?
That's a good question.
And the answer is yes.
But it turns out in many
experiments it doesn't look
that way, because you saw, for
those of you who looked at
that horrible-looking baby
picture, what would be an
equal positive powerful
picture?
Let's try this one.
Everybody agrees it's cute when
there's little children
around a birthday cake.
Smile, she smiles.
Powerful, unless it's
your kid, maybe.
Powerful image.
Powerful as the face
of the infant?
No.
So it's a really interesting
thing.
It's very hard to get positive
stimuli that are as potent as
negative stimuli.
You can get a million negative
stimuli from the internet and
it's very hard to get
very positive ones.
Having said that, we said, let's
just think about the
negative ones for the moment.
So our studies were
fMRI, PET, PET.
Ours were all with women.
And these were all with men.
And you could go, well,
why did that happen?
It's good that it's half women
and half men, because these
were Positron Emission
Tomography.
That involves injecting
radioactive stuff into people
to do that kind of imaging.
And many IRBs say, well, let's
not have women do it, because
they could be unknowingly
pregnant.
They could be.
And we shouldn't be giving
radioactive stuff just for an
experiment.
You could have debates about
that, but that's the thought.
Why not let the men get their
radioactive stuff?
We don't really need them.
Then so when we did this study,
we said, well, these
were all with men.
It seems in fairness we should
do it with women too.
We just thought that seemed
fair, kind of.
We didn't have any big
thought about that.
And again, we were getting left
amygdala and they were
getting right amygdala.
Pictures or films, different.
And this caught our eye,
that we had done
studies with women.
We were getting left amygdala.
They did it with men,
with right amygdala.
So deep scientists that we were,
Larry Cahill said, I'll
test men and women.
And we said, we'll test
men and women.
And here's what we found.
And these are averages, but
one critical thing that we
discovered-- we didn't know
this-- is that to the extent--
and these are averages, of
course these are averages--
that you compare men and women,
on average women have
better memory for emotional life
events, faster production
of autobiographical memories
to cues, more accurate in
dating memories.
So these dating studies are
pretty useful, because you
never know how accurate a person
is when they have a
memory for something.
What they do in the dating
studies is they have people
who are dating keep
diaries, for
example, in the fall semester.
And presumably those are
reasonably accurate.
They're filling them
in every day.
And then things happen over the
holidays and some people
remain dating and some don't.
So you go back to them in March,
and you go, in your
fall, when the two of you were
going out, tell us about what
you did in November.
And they can say who's
more accurate.
And they have almost a virtual
record, because they have the
responses that the men and
women put down that day.
And on average-- these
are averages-- the
women were more accurate.
And wives scored higher than
husbands on vividness of
memories for first date, last
vacation, recent argument.
So these are all averages.
There's lots of overlap, but
an average is that way.
And so Larry Cahill went
and did this thing.
And sure enough, again, as he
found before, for men, the
more they turned on the right
amygdala, the more certain
they were to remember
negative films.
And for women, the more they
turned on the left amygdala,
the more certain they
would remember
negative films on average.
Now, the thing to know is, on
average again, when you have
people rate the kinds
of pictures we
use, how do you think--
here it is.
This is one example where your
stereotype guesses probably
play out for the averages.
Who rates this as more scary,
or who says it's more scary,
men or women?
OK.
So positive or negative,
I should say
for positive or negative.
Here's the women, not finding
this a particularly--
on average, and there's
a range of responses--
positive picture.
Here's men going, pretty cool.
What DVD did that come from?
So people are always asking,
what does this really mean?
Are men just knowing they have
to do this or whatever?
Who knows?
There's no answer to this about
whether it's social
things or biology.
Certainly social things are
a big part of the story.
When we have people rate the
pictures in the scanner,
here's the women rating here's
the worst pictures.
And look at the men.
They're less willing to rate
these pictures as bad.
Again, psychologists who see
these data say, well, maybe
the men think they're never
supposed to rate them as bad,
because we're tough guys
and nothing's so bad.
I mean, I don't know.
Who knows?
But this is the ratings.
Now, if we look at the
activation of the men and
women on the left as they rate
them, the worse they rate it,
the more intense they find it,
the more they turned on their
left amygdala.
So at the moment they're rating
them, men and women
look very similar.
But when we relate it to their
memory, two things happen.
First, the women did have
superior memory to the men.
These were Stanford
undergraduates, probably not
that dissimilar on average to
the people in this room.
And quite strikingly, as you
saw it, activation in the
right hemisphere predicted
memory in men, and the left
hemisphere for women.
So I know there's been a
lot of right and left.
But here we think
was the message.
And it's kind of stood
the test of time a
little bit, on average.
What you see here is the part of
the left amygdala turned on
for women as they're
rating it.
The more intense,
the more active.
In relation to whether they form
a long term memory, the
more active, the more likely
they'll remember it.
And kind of the physical
overlap of the two.
In men, more active in that
amygdala on the left during
the rating, but doesn't
seem to be
involved in memory formation.
In the hippocampus, again,
overlap, overlap, overlap.
No apparent overlap
in the men.
So what happens literally in the
brain, I mean, literally
as far as we can measure it, in
women on average there was
more overlap between the parts
of the brain engaged as you
evaluate something and the parts
of the brain that make
the memory of that.
And in men, on average it was
as if, here's my emotional
rating on the right, and here's
what I'm going to
remember on the left.
Kind of a separation of
those processes in
the most simple sense.
Now here's a huge question.
Does this brain imaging study
tell us anything about whether
this is in the genes of boys and
girls as they're born or a
consequence of socialization
or both?
It's incredibly intuitive for
people to think that if you
see it in the brain it's
hardwired and genetic or
hormonal or something.
Brain imaging data never
tells you that.
It never tells you that.
It just tells you by this age,
this is what's going on.
And you don't have to know much
psychology to know that
we're all hugely influenced to
varying degrees, but we're all
hugely influenced by social
influences on what it is to be
a male or a female in our
families, in our cultures, in
our societies.
Whether something's in your
genes or in your culture, it
shows up in your brain.
And we can't tell those
two things apart.
Is this anything to do
with how we're born?
Is this anything to do with how
Hollywood pitches movies
that are about video game
battles versus chick flicks,
how they're pitching that and
trying to tell us we're
supposed to like something?
Who knows?
We can't tell if it's social
or genetic at all.
