Placeholder Image

Subtitles section Play video

  • Professor Paul Bloom: On Monday we--I presented an

  • introduction to evolutionary psychology, the looking at

  • psychology from an evolutionary perspective, and trying to make

  • a case and give some examples of how it can help illuminate and

  • illustrate certain aspects of how the mind works.

  • One of the advantages of an evolutionary perspective on the

  • mind is that it forces us to look scientifically at what we

  • would otherwise take for granted.

  • There are a lot of aspects of how we are and what we are and

  • what we do that seem so natural to us.

  • They come so instinctively and easily it's difficult,

  • and sort of unnatural, to step back and explore them

  • scientifically but if we're going to be scientists and look

  • at the mind from a scientific perspective we have to get a

  • sort of distance from ourselves and ask questions that other

  • people would not normally think to ask.

  • And the clearest case of this arises with the emotions.

  • And as a starting point there's a lovely quote from the

  • psychologist and philosopher William James that I want to

  • begin with. So, he writes:

  • To the psychologist alone can such questions occur as:

  • Why do we smile when pleased and not scowl?

  • Why are we unable to talk to a crowd as we talk to a single

  • friend? Why does a particular maiden

  • turn our wits upside down? The common man--[None of you

  • are the common man.] The common man can only say,

  • "Of course we smile. Of course our heart palpitates

  • at the sight of the crowd. Of course we love the maiden.

  • And so probably does each animal feel about the particular

  • things it tends to do in the presence of certain objects.

  • To the lion it is the lioness which is made to be loved;

  • to the bear the she-bear. To the broody hen,

  • the notion would probably seem monstrous that there should be a

  • creature in the world to whom a nestful of eggs was not utterly

  • fascinating and precious and never to be too-much-sat-upon

  • object which it is to her. Now, there's a few things to

  • note about this passage. First, it's incredibly sexist.

  • It assumes not just merely in reflexive use of phrases.

  • It assumes that--William James assumes he's talking to males,

  • male humans who sometimes take the perspective of male bears.

  • And so, it assumes a male audience.

  • You wouldn't normally--You wouldn't actually ever write

  • this way. A second point is it's

  • beautifully written and you're not--;also, not allowed to write

  • that way anymore either. It's poetic and lyrical and

  • if--William James characteristically writes that

  • way. I think he writes so much

  • better than his brother, Henry James,

  • an obscure novelist. [laughter]

  • Finally though, the point that he makes is a

  • terrific one, which is yes,

  • all of these things seem natural to us but the reason why

  • they seem natural is not because they are in some sense necessary

  • or logical truths. Rather, they emerge from

  • contingent aspects of our biological nature.

  • And so we need to step back. We actually--We need to step

  • back and ask questions like--and these are questions we're going

  • to ask--Why does poop smell bad? Avoid the temptation to say,

  • "Well, poop smells bad because it's so stinky."

  • The stinkiness of poop is not an irreducible fact about the

  • universe. Rather, the stinkiness of poop

  • is a fact about human psychology.

  • To a dung beetle poop smells just fine.

  • Why does chocolate taste good? Well, chocolate--The good

  • tastiness of chocolate isn't some necessary fact about the

  • world. It's a fact about our minds

  • that doesn't hold true for many other creatures.

  • And so, we have to step back and ask why to us do we find

  • chocolate appealing? Why do we love our children?

  • Don't say they're lovable. Many of them are not [laughter]

  • and, as William James points out, every animal,

  • most animals, many animals love their

  • children. They think their children are

  • precious and wonderful. Why?

  • Why do we get angry when people hit us?

  • Suppose somebody walked up to you and slapped you in the face?

  • You'd be afraid. You'd be angry.

  • Would you get sleepy, feel nostalgic,

  • suddenly desire some cold soup? [laughter] No.

  • Those are stupid alternatives. Of course if somebody slapped

  • us you would--we would get angry or afraid.

  • Why? Why do we feel good when

  • someone does us a favor? Why don't we feel angry?

  • Why don't we feel fearful? What we're going to do

  • throughout this course is step back and ask these questions.

  • We're going to ask questions nobody would have otherwise

  • thought to ask, where the common man wouldn't

  • address, and this is,

  • of course, standard in all sciences.

  • The first step to insight is to ask questions like why do things

  • fall down and not up? And I imagine the first person

  • who articulated the question aloud probably met with the

  • response saying, "What a stupid question.

  • Of course things fall down." Well, yes, of course things

  • fall down, but why? Why is our flesh warm?

  • Why does water turn solid when it gets cold?

  • These are natural facts about the universe,

  • but the naturalness needs to be explained and not merely

  • assumed. In this class we're going to

  • explore, throughout the course, what seems natural to us and

  • try to make sense of it. And to that end we have to ask

  • questions that you wouldn't normally ask.

  • We've already done this to some extent with domains such as

  • visual perception, memory, language and

  • rationality, but now we're going to move to the case where it's

  • maybe even somewhat more difficult to do this.

  • Now, we're going to start dealing with the emotions.

  • We're going to talk about the emotions, why they exist,

  • what they're there for, and how they work.

  • I want to start off with the wrong theory of the emotions.

  • And the wrong theory of the emotions is beautifully

  • illustrated in the television and movie series Star

  • Trek. In this alternative fantasy

  • world, there are characters, Mr.

  • Spock in the original Star Trek, Data in one of the

  • spin-offs, who are described as competent,

  • capable, in fact in many ways, super competent and super

  • capable people. But they're described as not

  • having emotions. Spock is described as not

  • having emotions because he's half Vulcan, from a planet where

  • they lack emotions. Data is an android who is said

  • to lack an emotion chip. This lack of emotions on

  • this--on a TV series does not hurt them much.

  • They're able to fully function. And in fact,

  • in a TV series emotions are often seen as a detriment.

  • You do better off without them. And there are many people in

  • sort of common sense who might think "Gee, if only I could just

  • use my rationality, think reasonably and rationally

  • and not let my emotions guide my behavior I'd be much better

  • off." It turns out that this is a

  • notion of how to think about the emotions that is deeply wrong.

  • And in fact, makes no sense at all.

  • Using the example of Star Trek, Steven Pinker,

  • in his book How the Mind Works, nicely illustrates

  • the problem here. He writes, "Spock must have

  • been driven by some motives or goals.

  • Something must have led him to explore strange new worlds,

  • to seek out new civilizations and to boldly go where no man

  • had gone before." Presumably, it was intellectual

  • curiosity that set him to drive and solve problems.

  • It was solidarity with his allies that led him to be such a

  • competent and brave officer. What would he have done if

  • attacked by a predator or an invading Klingon?

  • Did he do a handstand, solve the four-color map

  • theorem? Presumably, a part of his brain

  • quickly mobilized his faculties to scope out how to flee and how

  • to take steps to avoid a vulnerable predicament in the

  • future. That is, he had fear.

  • Spock did not walk around naked around the ship.

  • Presumably, he felt modesty. He got out of bed.

  • Presumably, he had some ambitions and drive.

  • He engaged in conversations. Presumably, he had some

  • sociable interests. Without emotions to drive us we

  • would do nothing at all. And you could illustrate this

  • scientifically. Creatures like Spock and Data

  • don't exist in the real world but there are unusual and

  • unfortunate cases where people lose,

  • to some extent or another, their emotions.

  • And you could look at these people and see what happens to

  • them. The classic case,

  • the most famous case, is that of a man called Phineas

  • Gage. Phineas Gage is the classic

  • Intro Psych examplean extremely poor guy,

  • poor schmuck. In 1848--He was a construction

  • foreman. In 1848 he was working at a

  • site with explosives and iron rods.

  • And due to an explosion, an iron rod passed through his

  • head like so. Imagine that rod shooting

  • upwards. It went under his eye and

  • popped out the top of his head. It landed about one hundred

  • feet away covered with blood and brains.

  • The rod itself weighed thirteen pounds.

  • Amazingly, Gage was not killed. In fact, he was knocked

  • unconscious only for a short period and then he got up and

  • his friends surrounded him and asked, "Are you okay?"

  • And they--And then they took him to the hospital.

  • On the way to the hospital, they stopped by a tavern and he

  • had a little pint of cider to drink, sat down and talked to

  • people. And then he had an infection,

  • had to have surgery. But when it was all said and

  • done he wasn't blind, he wasn't deaf,

  • didn't lose language, didn't become aphasic,

  • no paralysis, no retardation.

  • In some sense, what happened was much worse.

  • He lost his character. Here's a description at the

  • time of what Gage was like. And this is from Damasio's

  • excellent book Descartes' Error:

  • He used to be a really responsible guy,

  • a family man, very reliable,

  • very trustworthy. But after the accident he was

  • fitful, irreverent, indulging at times in the

  • grossest profanity, manifesting but little

  • deference for his fellows, impatient of restraint or

  • advice, a child in his intellectual

  • capacities and manifestations. He had the animal pleasures of

  • a strong man. His foul language is so debased

  • that women are advised not to stay long in his presence.

  • And he couldn't hold a job. He lost his family,

  • couldn't hold a job. He ended up in the circus.

  • He was in the circus going around the country with his big

  • iron rod telling everybody the story as they surrounded him and

  • clapped. There are other cases like

  • Phineas Gage, cases where people have had

  • damage to that same part of the brain, parts of the frontal

  • cortex. And what they've lost is they

  • basically lost a good part of their emotions.

  • And what this means is they don't really care that much

  • about things. They can't prioritize.

  • Damasio tells a case of one of his patients who was under the

  • pseudonym here of Elliot. And Elliot had a tumor in his

  • frontal lobe. And the tumor had to be removed

  • and with it came a lot of Elliot's frontal lobe.

  • And again, as a result of this, Elliot was not struck blind or

  • deaf or retarded, and he didn't become the sort

  • of profane character that Phineas Gage became,

  • but he lost the ability to prioritize.

  • He lost the ability to set goals.

  • Damasio describes him here:

  • At his job at an activity he would read and fully

  • understand the significance of the material [He works in an

  • office.] but the problem was he was

  • likely, all of a sudden,

  • to turn from the task he had initiated to doing something

  • else and spending an entire day doing that.

  • He might spend an entire afternoon deliberating on which

  • principle of categorization he should apply to files.

  • Should it be the date or the size of the document,

  • pertinence to the case or another?

  • He couldn't set his goals. He couldn't--He ended up not

  • being able to keep a job, not being able to deal with

  • people. And these are not men who have

  • lost their emotions. There is no case around where

  • you could have your emotions entirely blotted out.

  • But they lost a large part of their emotional capacity and as

  • a result, their rationality failed.

  • Emotions set goals and establish priorities.

  • And without them you wouldn't do anything, you couldn't do

  • anything. Your desire to come to class to

  • study, to go out with friends, to read a book,

  • to raise a family, to be--to do anything are

  • priorities set by your emotions. Life would be impossible

  • without those emotions. And so, there's certain themes

  • we're going to explore here. The first is this,

  • that emotions are basically mechanisms that set goals and

  • priorities and we're going to talk a lot about--in this class

  • and the next class about universals.

  • We're also going to talk about culture.

  • It turns out that cultures, different cultures,

  • including differences between America and Japan and the

  • American South and the American North,

  • have somewhat different emotional triggers and emotional

  • baselines to respond to. But at the same time,

  • as Darwin well knew, emotions have universal roots

  • that are shared across all humans and across many animals.

  • So, the agenda for this class and the next class is going to

  • go like this. First, I want to talk a little

  • bit about facial expressions, which are ways in which we

  • communicate our emotionsnot the only way,

  • but an important wayand look, in particular,

  • at the case of smiling because it's kind of interesting.

  • Then I want to look at one case study of a nonsocial emotion,

  • that of fear. I want to then deal with

  • feelings towards our kin, people we're genetically

  • related to, and then--and this will take us

  • to the next class, feelings towards non kin.

  • So first, faces. And as an introduction to faces

  • I have a brief film clip from Paul Ekman, who is one of the

  • world's great scholars in the study of facial expressions.

  • In Ekman's work, he presents us with

  • instructions on how to make different faces and identify

  • faces. Ekman actually has a sort of

  • more practical career along with his scientific career.

  • He trains police and secret service members to try to figure

  • out cues to honesty and dishonesty.

  • There's a very interesting New Yorker profile on him

  • by Malcolm Gladwell a few years ago, something you might be

  • interested in. But let's do one of his faces.

  • Please lower your brows and draw them together.

  • That means even those who aren't making eye contact with

  • me now.

  • Tense your lower and upper eyelids.

  • Don't pop out contact lenses but just tense them.

  • Stare. Your eyes can bulge somewhat.

  • [laughter] Okay. Now, the last part is important.

  • Press your lips together with the corners straight or down.

  • That's good. You got it.

  • [laughter] Okay. Just because you are not making

  • eye contact with me doesn't mean I can't see you.

  • Okay. . And what face is that?

  • What emotion does that correspond to?

  • Anger. There's all sorts of databases

  • of different faces from around. This guy--I don't know who he

  • is but he seems to be on a lot of these things [laughter]

  • but the thing is you don't need to rely on him.

  • You don't need to rely on Western faces.

  • Even if you go on line there's, by now, a lot of databases from

  • faces from all sorts of genders and national origins.

  • This is from a Japanese women facial expressions.

  • And there are some subtle and very interesting differences

  • across countries and across people, but there's also deep

  • universals. You don't have to work very

  • hard to figure out what these different facial expressions

  • mean. I want to give one more face

  • example because I want to focus on this a little bit.

  • This one's a little bit easier. Raise the corners of your lips

  • back and up, please.

  • [laughter] Raise your cheeks. Raise your lower eyelids if you

  • can. [laughter] They're smiling.

  • You're smiling. You can stop [laughter] smiling.

  • Yale is actually really big on smiling.

  • We have two of the world's experts on smiling.

  • This is Angus Trumble, the curator at the British Art

  • Gallery who wrote this wonderful book,

  • A Brief History of the Smile looking at the smile

  • in art. And this is my colleague,

  • Marianne LaFrance, who is actually not smiling in

  • that picture but she studies smiling and smiling in adults,

  • smiling in children, smiling across cultures,

  • and the different social uses of smiling.

  • And there are some interesting discoveries people have made

  • about smiles and about smiles and the emotions.

  • One--Oh. Well, one is that smiles are

  • universal. We know, for instance,

  • that young children smile. This is my son,

  • Zachary, when he was younger, not that weird-looking kid

  • [laughs] next to him.

  • [laughter] Thank God. [laughter]

  • And even blind children, children blind from birth,

  • will smile. They'll smile appropriately,

  • making an important point that smiling is not learned by

  • looking at other people's faces. Smiling is also not uniquely

  • human. Nonhuman primates smile as well.

  • Smiles are social signals. You might imagine that people

  • smile when they're happy. This is actually not the case.

  • It's not as simple as that. Rather, people smile when they

  • wish to communicate happiness and we know that from several

  • studies. There are some studies of

  • bowlers and the studies are very nice.

  • What they do is they film bowlers.

  • So, the bowlers do their bowling and sometimes they knock

  • down all the pins, which is called a what?

  • A strike. So a strike--and that's good in

  • the bowling world. So, they knock down all the

  • pins but what they don't do, is they don't smile after they

  • knock down the pins. They are being filmed.

  • They don't smile. Then they turn around to their

  • friends and give a big grin. Other studies have looked at

  • films of people who have just won Olympic gold medals.

  • Now, not surprisingly, people who have won Olympic

  • gold medals are very happy. This is good news to win an

  • Olympic gold medal. But they don't actually stand

  • on the podium grinning. Rather, they stand there with

  • their faces in a normal expression.

  • Then when they stand up and face the crowds,

  • there's a big smile. You can ask yourself whether

  • during sex, an activity where many people enjoy,

  • whether or not people smile during sex.

  • And you can discover this yourself with [laughter]

  • a partner or a mirror. [laughter]

  • So, there are other things we know about smiles.

  • There are different types of smiles.

  • There are actually quite a few different types of smiles that

  • are different in interesting ways.

  • This is Paul Ekman again.

  • Which one's a better smile? Who votes for the one on the

  • right? Who votes for the one on the

  • left? There are two different sorts

  • of smiles. The one on the right is a smile

  • of greeting. It's sometimes known as a "Pan

  • Am" smile. Pan Am is a now defunct airline

  • which had at that time--They were--They don't call them

  • stewardesses anymore but they're--the stewardesses would

  • come in and they would smile. That was part of their job.

  • But it was a big, fake smile, the Pan Am smile,

  • a smile to communicate "hello" and--but it's as opposed to a

  • smile where the communication is that of genuine happiness.

  • The difference is around the eyes.

  • It's not the mouth. It's the eyes.

  • A real happiness smile, what's known as a Duchenne

  • smile, after a neurophysiologist who studied it,

  • involves moving the eyes. What's interesting is about

  • only one out of every ten people can fake a Duchenne smile.

  • So, if you smile at somebody, and you just hate their guts

  • but you want to smile at them, it's--unless you're quite

  • gifted it's difficult to fake a really good, really happy smile.

  • You could--It's not difficult to study smiles in the real

  • world. You could look at politicians,

  • for instance. Politicians are often in

  • contexts where they have to smile a lot.

  • And what they do is they simply give the Pan Am smile.

  • The mouth moves up, particularly if somebody is

  • attacking their record or ridiculing them,

  • and they'll smile and--but it's not a sincere smile.

  • The eyes don't move. My favorite example of this was

  • a few years ago when there was a huge battle for the House

  • majority leader. And a guy named--a Republican

  • named John Boehner won this position in quite a heated

  • battle. And they took a picture of the

  • guy--This is not very nice. They took a picture of the guy,

  • Roy Blunt, as he stepped out. And he had lost and this was

  • his expression. [laughter]

  • And he's not really very happy [laughter]

  • as opposed to a smile like this, which is a real smile.

  • So, you have two sorts of smiles: A real happiness smile a

  • Duchenne smile--called--also known as the Duchenne smile,

  • and then a Pan Am smile, or greeting smile.

  • And you'll use each of those smiles at different points in

  • your day and in your life. It turns out that these

  • different smiles have real psychological validity.

  • They seem to sort of reflect deep differences in your mood

  • and emotions and thoughts. Ten-month-olds,

  • for instance, give different sorts of smiles.

  • When their mother approaches there they give a real happiness

  • smile. Then when a stranger approaches

  • or someone else approaches there they'll tend to give more of a

  • greeting smile. John Gottman studied married

  • couples. And John Gottman does a lot of

  • work--Well, what he does is he looks at film clips of couples.

  • And by analyzing the film clips he tries to predict will their

  • marriages survive. And one of his cues--There's

  • different cues. Incidentally,

  • sort of side topic: The death knell for a marriage

  • for Gottman--This is his big finding.

  • It's not if they fight a lot. It's not they scream at each

  • other. It's not even if they hate each

  • other. The death knell of a marriage

  • is contempt. And so, if he shows these

  • clips: I walk in, "Honey, I'm home," and my

  • spouse has the look of contempt, it's a bad sign.

  • [laughter] But another clue is the sort of

  • smiles they give when they see each other when they walk into

  • the lab. If it's a true happiness smile,

  • that's actually bodes better for the relationship than a Pan

  • Am, or greeting smile. Finally, studies have been done

  • of college yearbook photos looking at people thirty years

  • later. And it turns out that there's a

  • correlation, a reliable relationship between how happy

  • somebody is now and back thirty years ago in their yearbook

  • photo--what sort of smile they're giving.

  • There is some evidence for a third sort of smile.

  • This is known as a coy smile or an appeasement smile.

  • This is sort of a very specialized sort of smile.

  • This is a smile of embarrassment or stress.

  • You give it when you want people to like you,

  • you want to join in; you want to make people feel

  • positive about you. But you're in,

  • sort of, a high-stress situation often with some sort

  • of risk. And what you do is you sort of

  • you turn away. There's no eye contact.

  • You turn away and kind of give this-- And this actually shows

  • up in other primates. Here's a nice picture.

  • [laughter] So, the rhesus monkey bites her

  • own infant, and the infant gives a scream and then the

  • submissive, coy smile. And it also shows up in human

  • infants. Here's a nice clip of a coy

  • baby smile. I'll walk you through it.

  • The baby is being approached, [laughter]

  • goes like this , smiles like this ,

  • and then the aversion . Yeah.

  • Babies are cute. [laughter]

  • Any questions at this point about smiling?

  • What are your smiling questions? [laughter] Yeah.

  • Student: Do nonhuman primates' smiles [inaudible]

  • Professor Paul Bloom: That's a good question.

  • I don't know. There's evidence that the coy

  • smile shows up in non--The question was,

  • "Do nonhuman primates give the same smiles that humans do?"

  • such as a distinction between the Pan Am smile,

  • a greeting smile, versus a genuine smile of

  • happiness? I don't know.

  • I'll find out for you for next class though.

  • That's a good question. Yeah.

  • Student: How come some people's smiles are better than

  • other people's smiles? Professor Paul Bloom:

  • How come some people's smiles are better than other people's

  • smiles? The non-interesting

  • psychological answer, some people are better looking

  • and there's more thing-- [laughter]

  • but the deeper answer is some people are better able to smile.

  • Some people are better able to use the cues to express true

  • happiness. There's something else about

  • smiles which is going to come up, which your question raises,

  • I think, which is going to come up in--when we talk about

  • emotional contagion and actually,

  • some issues of morality. Smiles are extremely contagious.

  • So, what I'd like people to do--If you're sitting next to

  • somebody, please turn around and find someone next to you and

  • look at them. Don't do anything.

  • Just look at them. Whoever is being looked at,

  • look back. [laughter]

  • This is not-- [laughter] Please arbitrarily decide.

  • Okay. Please arbitrarily decide on

  • the smiler. That will be--No,

  • not at me, at each other, [laughter]

  • and that will be the person--If you are unable to resolve this

  • dispute--yes, you two, please--if you are

  • unable to resolve this dispute, the person to the right of me

  • will be the smiler. So, look at each other

  • expressionless. [laughter]

  • Now, the person who is the mandated smiler,

  • [laughter] on three, please smile.

  • One, two, three. [laughter] Okay.

  • [laughter] Worst class demo ever

  • [laughter] but if one could imagine more

  • restrained circumstances, it is actually extremely

  • difficult to be facing somebody who's really smiling at you and

  • not smile. This is true,

  • by the way, for virtually every other emotion.

  • The phenomena is known as "emotional contagion," where if

  • you're facing somebody, for instance,

  • and they're--they look at you in a face of absolute rage,

  • it is very difficult to just sit there without your own face

  • molding in accord to their own. And the reasons why this

  • happens and how that works is something we'll talk about later

  • on. So that's--One more question.

  • Yes. Student: [inaudible]

  • Professor Paul Bloom: I don't know if that's--The

  • question is, "Is there a difference between

  • smiling with your teeth versus just your lips closed?"

  • There probably is. That's not a main smile

  • difference but my bet is that there probably is a difference.

  • And my bet also is that that sort of distinction,

  • how much teeth you show when you smile,

  • is the sort of thing that would show regional and country by

  • country differences. For instance,

  • there's been research finding that people in England smile

  • different from people in the United States.

  • And I think that those are the sort of contrasts that you would

  • expect to find in cross-cultural differences.

  • Every culture is going to have Pan Am smiles,

  • happiness smiles, coy smiles, but the variation

  • of that sort is something which will vary as a result of how

  • you're raised and the people around you.

  • I want to deal with a few emotions in this class and next

  • and the first case study of an emotion I want to deal with is

  • the emotion of fear. And I want to deal with fear

  • for different reasons. One reason is it's a basic

  • emotion, it's universal. All humans have it.

  • Many nonhumans, probably most nonhuman,

  • species have it too. And it also brings us back to

  • the lecture on behaviorism where we talked about classical

  • conditioning and different theories of what people are

  • afraid of. It's a nonsocial emotion.

  • What I mean by this is it's possible, of course,

  • to be afraid of a person, but unlike an emotion like

  • gratitude, it's not intrinsically social.

  • You could be afraid of falling off a cliff or something.

  • It has a distinctive facial expression again.

  • This is a famous picture of Lee Harvey Oswald who was being

  • assassinated by Jack Ruby. And this is the detective's

  • face standing there, a mixture of fear and anger

  • the face being drawn back in a universal expression that every

  • human everywhere would be able to recognize.

  • So, the basic question to ask is "What are we afraid of?"

  • And the answer's a little bit interesting.

  • We're afraid of spiders, snakes, heights,

  • storms, large animals, darkness, blood,

  • strangers, humiliation, deep water, and leaving home

  • alone. We are afraid of other things

  • too but those are big things to be afraid of.

  • I'm not even going to ask. If there's somebody who--in

  • this room, who's not afraid of any of those things?

  • You're a tougher person than I am.

  • These are universal fear elicitors.

  • Why? What do they have in common?

  • Why would you be afraid of those things?

  • And the answer is--And why would--why are there so few

  • people afraid of guns, cars, and electrical outlets?

  • The answer is not particularly surprising.

  • These are things that--something's ticking over

  • there. These are things that are scary

  • in our ancestral environment. More particularly,

  • these are things that through the course of human evolution

  • have been dangerous to us. And so, we are afraid of these

  • things and not so afraid of these things;

  • similarly for nonhuman primates. So, chimpanzees are afraid of

  • certain things and they can often develop phobias for

  • certain things, but the phobias they develop,

  • the fears they develop, are things like spiders and

  • snakes. There was a nice study done in

  • urban Chicago, in the inner city of Chicago.

  • And they asked children raised in the inner city,

  • "What are you most afraid of?" And you might think they would

  • say, "I'm afraid of being shot. I'm afraid of guns.

  • I'm afraid of being killed by somebody or being harmed by

  • somebody. I'm afraid of being run over by

  • a car." The two biggest fears of

  • children in urban Chicago are that , snakes and spiders,

  • even though many of these children have probably never

  • seen a snake outside of a zoo in their lives.

  • These are natural fears. There is some research done by

  • the psychologist Judy DeLoache at University of Virginia where

  • she's studying babies' fears of spiders and snakes,

  • babies obviously who, since their parents are normal,

  • have not yet seen spiders and snakes.

  • There are various ethical reasons why you can't show

  • babies--you can't try to construct phobias in babies of

  • spiders and snakes but the research she's finding using

  • more indirect methods finds, as one would expect,

  • these are what psychologists would call "pre-potent stimuli";

  • that is, these are things that naturally elicit fear and

  • concern. And that's all I have to say

  • about fear. I want to turn for the rest of

  • this lecture and for next lecture next week to the social

  • emotions. And the social emotions can be

  • broken down into two categories. Bless you, bless you.

  • Those emotions you feel towards your kin, towards your genetic

  • relatives, and those emotions that you feel towards the people

  • you're not related to but interact with.

  • And I want to focus particularly on emotions that

  • generate kind or altruistic behavior.

  • "Altruism" is the biologists' term meaning kindness,

  • generosity, and evolutionary biologists have worked really

  • hard to explain why animals might evolve to be kind.

  • A very old, very wrong view of evolution is that evolution has

  • shaped animals such that they're merely survival machines.

  • If so, then from an evolutionary standpoint any

  • kindness towards an animal--that an animal shows towards another

  • animal--is a mystery. If evolution wired us up simply

  • to survive, then it's a puzzle why animals would relate

  • positively to other animals. But of course, that's not true.

  • Here's a simple example showing it's not true.

  • Imagine two genes, two sorts of animals each

  • containing their own gene. Gene "A" makes an animal care

  • for its offspring. Gene "B" makes an animal care

  • only for itself. Imagine what will happen in the

  • next generation. Plainly, Gene "A" will win out.

  • It's a very simple case. An animal who has evolved a

  • brain that says, "Take care of your offspring"

  • will do much better from a natural selection point of view

  • from an animal who has evolved a brain that says,

  • "Eat your offspring." The animal that eats its

  • offspring, those genes are a biological dead end.

  • What matters then is not survival, per se.

  • What matters is reproduction. And so, that simple fact is why

  • we would expect animals to care for their children,

  • because children are the means through which genes replicate.

  • But it gets a little bit richer than that.

  • And this is one of the major revolutions in evolutionary

  • biology over the last half century.

  • Forget about the animal a bit and take another perspective.

  • Take a perspective of the cold virus.

  • People have been sneezing in the front row.

  • Now, you're coughing. Thank you.

  • Why do you sneeze when you get a cold?

  • Here's not a-- Point made. Here is--Here's not a bad

  • answer. You sneeze because you've got

  • all these germs inside you and your body wants to get the germs

  • out, so you sneeze. It's not that it's totally

  • wrong, but it's not bad. The real answer is a little bit

  • more interesting. Don't look at it from the

  • person's perspective. If you have a cold,

  • try to get away from your own selfish perspective,

  • "I have a cold." Look at it from the perspective

  • of the cold virus. The cold virus has evolved just

  • as much as you evolved. And it's evolved due to

  • survival and reproduction. What the cold virus does is

  • evolve different strategies to cause it to reproduce.

  • And what it does is--one way to reproduce is to occupy other

  • animals and manipulate their bodies so as to expel it.

  • From this point of view then, the reason why you sneeze when

  • you have a cold is that your cold--the cold virus is using

  • your body as a tool to replicate itself.

  • From this person--this perspective, a person is just a

  • germ's way of making other germs.

  • And there's tons of other examples of this.

  • There's a parasite known as toxoplasmosis that lives in the

  • bodies of rats. But it gets passed on when the

  • rats get eaten by cats. And then it ends up in the

  • cats' feces and then it ends up back in rats.

  • If you are a rat and you have toxoplasmosis,

  • you are perfectly healthy except for one thing.

  • The toxoplasmosis rewires your brain and it makes you less

  • afraid of cats. Now, again, this is not some

  • sort of bizarre quirk of a humorous god.

  • Rather, it's because this is a perfectly--this is the adaptive

  • strategy of the toxoplasmosis virus.

  • In fact, a real powerful virus would skip the respiratory

  • system altogether, even better than a cold virus.

  • What it would do is it would take over the brain and it will

  • make people want to run around and have sex with other people

  • and kiss them on the mouth. And in fact,

  • there is some evidence that this happens.

  • There's some evidence, for instance,

  • that one of the effects of sexually transmitted diseases

  • like syphilis is it arouses the libido,

  • makes people more sexually engaged, because this is part of

  • the strategy through which these viruses replicate themselves.

  • Imagine a virus, for instance,

  • that captured an animal's brain and then modified the animal's

  • brain such that the animal would run out and bite other animals

  • so as to pass on the virus. And then, of course,

  • you would call that virus "rabies."

  • Along these lines, the evolutionary biologist

  • Richard Dawkins took the general step of suggesting that animals

  • are the vehicles through which genes exploit to reproduce.

  • From this perspective, an animal is just the

  • person's--is just the gene's way of creating another animal.

  • Well, as psychologists, what benefit does that--does

  • this way of analysis give us? It actually can help us explain

  • altruism. So, which genes are going to

  • survive? Well, the genes that survive

  • are going to be the ones that make the most copies of

  • themselves. Animals are vehicles through

  • which genes reproduce. An animal's merely the gene's

  • way of making another gene. Hence, selfish genes will lead

  • to altruistic animals because, to the extent that evolution

  • operates at the level of the genes,

  • there's no hard and fast distinction between your own

  • body and someone else's body. And here's an illustration by

  • the biologist Haldane. So, Haldane was once asked,

  • "Would you lay down your life for your brother?"

  • And he responded, "No, but I would gladly give my

  • life for three brothers or five nephews or nine first cousins."

  • Now, he's joking. You don't actually do the math

  • if you're normal. But what he's capturing is the

  • logic, the ultimate causation of our feelings towards our kin.

  • Our genes have wired us up--our brains up to love our children

  • and love our kin because, in this way,

  • our genes manage to replicate themselves.

  • And in fact, you get his calculations by

  • looking at genetic relatedness. The genetic relatedness,

  • from an evolutionary standpoint, affects how much you

  • care for other people. From the standpoint of your

  • genes, you dying for the life of three brothers is an excellent

  • compromise because the genes replicate by fifty percent more.

  • If you imagined--;So, here is his calculations.

  • If you imagined a choice between this one gene that makes

  • the animal choose to die and the other gene that makes an animal

  • choose for its brothers to die, the gene that sacrifices the

  • body it belongs to will make more copies in the future.

  • And there's an interesting irony to this.

  • The selfish gene theory is often seen as sort of a

  • cold-blooded evolutionary analysis,

  • but it provides a scientific basis for real,

  • genuine altruism, for really arguing that,

  • from the standpoint of the genes, there really is no hard

  • and fast difference between yourself and another person.

  • From this perspective, we can start to answer some

  • interesting questions at least about nonhumans.

  • When a new male lion takes over a pride what he does is kill all

  • the remaining cubs and any lionesses undergo spontaneous

  • abortions. This all might seem very cruel

  • but from a genetic standpoint it makes sense.

  • The other cubs are genetic competition for him.

  • They do not have his genes. Moreover, only once they're out

  • of the way can he reproduce and copulate with the females.

  • The females do their spontaneous abortions because

  • that's a reliable adaptive trick.

  • These cubs are not going to survive once they are born so

  • the female's best strategy is to get rid of them and start anew.

  • From a psychological point then, animals have evolved to be

  • nice to their kin, particularly their children,

  • and particularly in birds and mammals.

  • Birds and mammals invest in quality and not quantity,

  • as opposed to fish and reptiles.

  • For birds and mammals, we don't have many kids but--so

  • we devote a huge amount of psychological energy to

  • protecting the ones that we have.

  • Moreover, the kids we have are vulnerable for long periods of

  • time and require our resources. So, there's various

  • psychological mechanisms that this gives rise to.

  • One is how parents or how adults in general respond to

  • children. Another one is how children

  • respond to parents. And I'll briefly talk about a

  • few of these phenomena.

  • Small animals make distress calls.

  • They chirp, they mew, they bleat or they cry.

  • The governing of a distress call is actually an extremely

  • delicate high-wire act for any young organism from an

  • evolutionary point of view. It has to on the one hand be

  • annoying enough to actually generate help,

  • to get people to help you, to feed you,

  • to pick you up, to take you and put them next

  • to you. On the other hand,

  • it can't be so annoying that the people around you kill you

  • [laughter] and so it's complicated.

  • But, from your point of view, you're wired up to respond to

  • them. That sound is,

  • at very minimum, extremely annoying.

  • And it's more--it's not annoying because of its volume

  • or pitch. It's annoying because your

  • brains are wired up so that that baby cry is going to drive you

  • up the wall. On the more positive side,

  • babies are cute. I got this from Google Images,

  • typing in "cute baby," [laughter]

  • getting rid of the porn and [laughter]

  • coming on to that. No, no, Playboy,

  • but anyway it was over that. [laughter]

  • And do not be tempted to say, "Isn't it wonderful that the

  • way nature works is that babies are cute?

  • Otherwise we would have killed them."

  • [laughter] That's not the right story.

  • If--Babies are not--Human babies are not,

  • sort of, metaphysically cute. If Martians came down they

  • wouldn't say, "Oh, cute baby."

  • Rather, they're cute because of how our brains are wired up.

  • They're cute because there are certain cues that correspond to

  • the way our brains work. And in fact,

  • this is how it works for all mammals.

  • So, babies have these big, protruding foreheads,

  • an upturned little nose, chubby cheeks and big eyes.

  • Those are the ingredients for cute.

  • Stephen Jay Gould has a wonderful essay where he

  • discussed this, looking at the evolution of

  • Mickey Mouse from the Walt Disney character.

  • Mickey Mouse starts off as an ugly, little rodent.

  • [laughter] Over time he gets cuter and

  • cuter and cuter as the artist converged on more and more

  • baby-like features. Studies of adults show what's

  • known as a baby-face bias. This is not unique to the

  • United States. The same studies have been done

  • in Asia. You find a baby face in an

  • adult, Leonardo DiCaprio, to be particularly naive,

  • helpless, kind and warm. And in mock trials,

  • people with baby faces are more likely to be found innocent than

  • people like Ben Affleck, [laughter]

  • who do not have baby faces. [laughter]

  • Now, one question which is going to come up for an entire

  • lecture later on is "who is sexier, the baby faced man or

  • Testosterone Man?" here .

  • [laughter] And I am going to ask actually

  • for a vote because I'm going to return to this.

  • I do not--I only want the men to vote, please.

  • Who would go for--And forget the fact that he looks sort of

  • unhappy. Who would go for Ben Affleck

  • here? Okay.

  • [laughter] Who would go for Leonardo?

  • Okay. [laughter]

  • Well, the women votes would actually be more complicated.

  • We will discuss when we get the lecture on sex.

  • Your choice will depend on where you are in the menstrual

  • cycle. [laughter]

  • Now, so far, we're talking about how babies

  • respond to--We're talking about our responses to babies.

  • What about babies' responses to us?

  • Well, there's a very old theory known as the "Cupboard Theory"

  • proposed by the behaviorist B.F. Skinner which argues that

  • babies' attachment to their parents is because the parent

  • provides food, characteristically breast milk,

  • but it could be food from a bottle or whatever.

  • And because of operant conditioning,

  • the baby is driven towards the adult.

  • An alternative theory is that of Bowlby, which is that they're

  • drawn to their mother for comfort and social interaction

  • as well as fear of strangers. To test this,

  • the psychologist Harlow performed a series of ingenious

  • experiments with nonhuman primates distinguishing between

  • what he called "wire mothers" and "cloth mothers."

  • And you'll see illustrations of this to follow.

  • Wire mothers are mothers that are built that they give food.

  • They have a little nipple attached and you can drink from

  • it and give food to the baby. And that's the baby's source of

  • food. Cloth mothers don't give any

  • food but they give warmth and comfort.

  • There was a while in the psychology department where one

  • professor was known to be extremely supportive to his

  • students but didn't really provide much warmth.

  • And he was known as the cloth mother.

  • And another one was very productive and everything but

  • provided no love. And she was known as the wire

  • mother. But anyway, I'll show you the

  • movies. I have to warn you this third

  • and final movie is an example of why this research is not

  • currently done, but it illustrates an important

  • scientific point. Oh.

  • Now him-- I think I'm-- They're just more Google Images.

  • [laughter] I think I'll--I want to begin

  • next class by wrapping up and explaining the Harlow studies in

  • more detail and what they tell us.

  • And then we'll move towards altruism, towards non kin.

  • I'll see you next week.

Professor Paul Bloom: On Monday we--I presented an

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it