continuing on the theme of emotions.

"Emotions" is a two-part lecture and we're continuing

along certain themes. I want to begin by responding

to a question which was raised in the last class concerning

smiling and nonhuman primates. It was a very good question.

The issue was: we know that humans have

different sorts of smiles to convey different sorts of

information. The question was,

"do nonhuman primates, like chimpanzees or gorillas or

gibbons, have the same many sorts of smiles?"

So, I contacted the world's expert on smiling,

who did not return my e-mails. So, I contacted the second

world's expert on smiling who told me that the answer is "no,"

that primate--nonhuman primate smiles actually correspond

almost entirely to appeasement smiles.

They're "don't hurt me" smiles. They're equivalent to the "coy

smile" that we saw on humans. But that nonhuman primates do

not use smiles for greetings; there's no equivalent to the

"greeting smile" or "Pan Am smile";

nor do they use them as genuine expressions of happiness.

There's no equivalent to the "Duchenne smile."

That's as far as I know. If the world's expert gets back

to me and says something different, I'll keep you posted.

Another thing. Going back to the beginning

theme of the class, what we started--just to

review, we talked about the different functions of emotions.

And then we talked about smiling and facial expressions.

And then we turned to some--to a nonsocial emotion,

the case of fear. And then we shifted to social

emotions. And we talked about social

emotions towards kin and the special evolutionary reasons

that would lead them to evolve. And as we were ending,

we were talking about the relationship between an animal

and its children, particularly in cases like

humans and birds and mammals where there tends to be a close

relationship with our children. We invest in quality,

not quantity. I might produce very few

children in my life. And my evolutionary trick then

is to focus very intently on them and make sure they survive.

If I were to produce 100 children, I could stand to lose

a few, but if I just produce five in my lifetime or two or

one, they become very precious to me.

And so, the story of the evolution of a species like us

involves a long period of dependence and deep,

deep bonds between the parent and the child.

And that's part of what I talked about,

how parents respond to children.

And I want to begin this class by giving an illustration from a

documentary about parental response to children,

but I want to give it in a species that's not us.

And here is why. I'll explain why with an

analogy. I have a friend of mine who

studies the psychology of religion.

He studies why people hold religious beliefs.

And he tells me that when he's talking to a non specialist,

somebody not in the field, he doesn't ever tell them,

"Yeah, I'm really interested in why people believe in the Bible

or why people light the candles on Sabbath or why people go to

church" because these are religions that people around

here hold, and if you tell people you

study them they'll sort of be puzzled, "why would you want to

study something like that" or offended.

If you want to talk about the psychology of religion to an

audience like this, what you do is you start with

the exotic. So, you start by talking about

people who put butter on their heads.

Dan Sperber talks about a culture where the men put butter

on their heads in the summer. And it kind of melts and that's

part of--one of the things that they do or--you talk about a

culture that believes in spirits or that trees can talk.

You say you're studying it and they say, "Oh,

that's interesting. I wonder why they believe that?"

And you use that as a way to look at more general facts that

exist even in our culture. You use the fact that we don't

take the exotic for granted as a way to motivate the scientific

study of things we do take for granted.

And this is, of course, true more generally.

This was the point in the William James quote when he

talked about things that are natural to us and noticed that

some very odd things are equally natural to other species.

And it's true, I think, in particular when we

talk about things like the love we have for our children.

So, one way to look at the love we have for our children

scientifically, isn't to look at it head-on,

because the love we feel towards our own children feels

sacred, it feels special, but look at it in other species.

And so, one of the nicest illustrations of this is the

Emperor penguin, which was--which--whose

childcare and mating practices were dramatized in a wonderful

movie called "March of the Penguins."

And this is interesting because they had this incredibly

elaborate and quite precarious system of generating and taking

care of offspring. So, I want to show you a brief

clip of the movie to illustrate some parts of this.

What they do at the beginning, which is not--which leads up to

this, is they take a very long trek from the water to their

breeding grounds. Their breeding grounds is--are

protected from the wind and they're on a firm piece of ice

so they could hold the whole pack.

They do the breeding there and it's there that the eggs are

created. So, this is where the movie

begins at this point. "March of the Penguins" was the

second best--second most popular documentary of all time,

beaten only by "Fahrenheit 9/11."

And people responded to it in different ways,

which are informative when we think about the generalizations

you could make from animal behavior to human behavior.

Some conservative commentators saw this as a celebration of

family values, such as love and trust and

monogamy. Some liberals,

who hate everything that's good and true, [laughter]

responded by saying, "Well, yeah,

they're monogamous for one breeding season.

It's a year. Then they go and find another

mate. If you add it up,

it's pretty slutty." [laughter]

I think more to the point, people were impressed and

stunned by the rich and articulate and systematic

behavior that these animals were showing.

Plainly, they didn't pick it up from television,

movies, culture, learning, schooling,

and so on. To some extent,

this sort of complicated behavior came natural to them.

And it's understandable that some proponents of intelligent

design, or creationism, pointed to this as an example

of how God creates things that are deeply, richly intricate so

as to perpetrate the survival of different animals.

From a Darwinian standpoint, the Darwinian would agree with

the creationist that this couldn't have happened by

accident, this is just far too

complicated, but would appeal to the--to this as an exquisite

example of a biological adaptation,

in particular a biological adaptation regarding parental

care to children shaped by the fact that children share the

parents' genes and so parents will evolve in ways that

perpetrate the survival of their children.

Then there's the other direction, which is how children

respond to parents, how the young ones are wired up

to resonate and respond in different ways to the adults

around them. And we quickly talked about

some different theories of this. And I'll just review what we

talked about last class. Babies will develop an

attachment to whoever is closest.

They'll usually prefer their mothers because their mothers

are typically those who are closest to them.

They'll prefer her voice, her face, her smell.

It used to be thought that there is some sort of magical

moment of imprinting that when the baby is born,

the baby must see his or her mother and "boom," a connection

is made. If the baby doesn't,

terrible things will happen with attachment later on.

This is silly. There is no reason to believe

there's some special moment or special five minutes or special

hour. It's just in the fullness of

time babies will develop an attachment to the animal that's

closest to it. They will recognize it as,

at an implicit level, at an unconscious level,

as their kin. Well, how does this work?

How does the baby's brain develop--come to develop an

emotional attachment to that creature?

Well, you remember from Skinner that operant conditioning could

provide a good answer to this. And this is known as the

"Cupboard Theory," which is babies love their moms because

their moms provide food. It's the law of effect.

It's operant conditioning. They will approach their

mothers to get the food from them.