Steven Pinker: How Do Nature And Nurture Combine To Make Us Who We Are? Psychologist Steven Pinker describes how far we've come in understanding how both nature and nurture make us ... us.
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How Do Nature And Nurture Combine To Make Us Who We Are?

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How Do Nature And Nurture Combine To Make Us Who We Are?

How Do Nature And Nurture Combine To Make Us Who We Are?

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GUY RAZ, HOST:

On today's show, we're asking a very important question, which is - who are we?

STEVEN PINKER: OK (laughter).

RAZ: By the way, do you have the answer? Do you know who we are?

PINKER: I know who I am. (Laughter) But, you know, I have an inkling of who we are.

RAZ: This is Steven Pinker.

PINKER: I am a professor of psychology at Harvard University. And I write books on language, mind and human nature.

RAZ: So yeah, what is it that makes us who we are?

PINKER: Well, there are some intricately complex circuitry in the brain, fabricated over millions of years by natural selection, that equips us with a set of motives and emotions and mechanisms for learning and thinking that make us who we are.

RAZ: OK. There's a lot to unpack here. So to begin to understand what Steven Pinker just said and to understand what accounts for the differences between us, we kind of need to understand how far we've actually come in trying to figure this all out. So Steven, can you help us with this?

PINKER: OK. I'll do my best.

RAZ: OK. Just to get us started, human beings have debated nature versus nurture for hundreds, even thousands of years. That is whether who we are - our personalities, our behaviors - are either entirely inherited from our parents or whether it all comes from the environment around us, that when we're born, our minds are basically like blank slates.

(SOUNDBITE OF TED TALK)

PINKER: And that all of its structure comes from socialization, culture, parenting, experience.

RAZ: That was Steven Pinker on the TED stage back in 2002. And this idea of the blank slate, it was especially popular in the second half of the 20th century. And it meant that a lot of us went through high school biology hearing stuff like this...

(SOUNDBITE OF TED TALK)

PINKER: Man has no nature, from the historian Jose Ortega y Gasset. Man has no instincts, from the anthropologist Ashley Montagu. The human brain is capable of a full range of behaviors and predisposed to none, from the late scientist Stephen Jay Gould.

Now, why should it have been such an appealing notion? Well, there are a number of political reasons why people have found it congenial. The foremost is that if we are blank slates, then, by definition, we are equal because zero equals zero equals zero. But if something is written on the slate, then some people could have more of it than others. And according to this line of thinking, that would justify discrimination and inequality. Another political fear of human nature is that if we were blank slates, we can perfect mankind, the age-old dream of the perfectibility of our species through social engineering, whereas if we're born with certain instincts, then perhaps some of them might condemn us to selfishness, prejudice and violence.

First of all, there are a number of reasons to doubt that the human mind is a blank slate. And some of them just come from common sense. As many people have told me over the years, anyone who's had more than one child knows that kids come into the world with certain temperaments and talents. It doesn't all come from the outside. Oh, and anyone who has both a child and a house pet has surely noticed that the child exposed to speech will acquire a human language, whereas the house pet won't, presumably because of some innate difference between them.

(LAUGHTER)

PINKER: And anyone who's ever been in a heterosexual relationship knows that the minds of men and the minds of women are not indistinguishable.

RAZ: So for years, the debate about nature versus nurture has been just that, a debate. It's one or the other. But Steven Pinker has mainly argued that this shouldn't be a debate, that who we are comes down to both our genes and our environment.

PINKER: It's a mistake to think that if there is an effect of the environment that shows that we're blank slates. Or conversely, if there is such a thing as human nature, then we are robots. And we're programmed to walk into walls and be completely insensitive to our environment. It's just the wrong way to think about it.

RAZ: The right way to think about it, he says, starts with our genome.

PINKER: Well, the fact that we behave like humans and not like orangutans or chimpanzees or squirrels is very much determined by our genome.

RAZ: So our genome sets us apart from animals. But it also sets us apart from each other.

PINKER: The differences between two individuals shows a pretty strong statistical effect of our genes.

RAZ: But then here's where environment comes in.

PINKER: Aside from the fact that we have unique genomes, we have a unique history of development. That is, the process by which our brain gets wired up in utero and the first few years of life is not dictated down to the last synapse by the genes. But there's space for random twists and turns in the wiring up of the brain that make even identical twins somewhat different. And of course, we have our unique lifelines. We have a unique trajectory of experience as we make our way through the world and make decisions. And the decisions affect the way the world treats us, including other people. And we take away lessons from how we've been treated. And so we set off with a combination of our unique genome and our chain of experiences.

RAZ: OK. Just to clarify, our environment is helping mold our genes.

PINKER: Oh, obviously. That is, if I was brought up as an Apache or as a Japanese samurai or as a Romanian peasant in the 14th century, there would be differences, undoubtedly, compared to who I am now.

RAZ: So we just talked to Sam Sternberg about, you know, like, how being a morning person is possibly embedded in our genetic code. So what else are we probably born with?

PINKER: So we know that intelligence has a big heritable component, which doesn't mean that it is completely determined by our genes. But it does mean that some of the differences among people can be attributed to differences among their genes. We know that differences in personality - how conscientious, how agreeable, how neurotic, how extroverted - are influenced by our genome. And even behavioral traits such as, how likely are you to be a smoker or an alcoholic - all of them show some influence of our genetic endowment.

RAZ: And even though we can now probe our genomes to actually test some of these things out, Steven Pinker says there's another slightly bizarre, old-fashioned method.

PINKER: Such as looking at similarities between identical twins who were separated at birth.

RAZ: Because identical twins separated at birth share all of their genes but, of course, not their environments.

PINKER: And they show that there is a pretty hefty statistical influence of the genes. That is, if you know what one identical twin is like, you can make a lot of predictions about the other one who he or she may never have met, who may have grown up an ocean and a culture away.

(SOUNDBITE OF TED TALK)

PINKER: My favorite example is of a pair of twins, one of whom was brought up as a Catholic in a Nazi family in Germany. The other was brought up in a Jewish family in Trinidad. When they walked into the lab in Minnesota, they were wearing identical navy blue shirts with epaulets. Both of them like to dip buttered toast in coffee. Both of them kept rubber bands around their wrists. Both of them flushed the toilet before using it, as well as after. And both of them like to surprise people by sneezing in crowded elevators to watch them jump.

(LAUGHTER)

PINKER: Now, the story might seem too good to be true, but when you would administer batteries of psychological tests, you get the same results. Namely, identical twins separated at birth show quite astonishing similarities.

RAZ: That's just unbelievable. So then, like, even things, like, habits or personality quirks are more or less assigned at birth?

PINKER: Well, they're influenced at birth. I wouldn't say they're assigned because there are probably some unpredictable changes that occur as the brain kind of gels in the first couple of years of life. There are changes that unfold over the lifespan. Whether they are a response to outside forces or if they're just the way that the brain spontaneously develops, we don't really know.

RAZ: Yeah.

PINKER: There are certainly ways in which anyone can be damaged. If you undergo trauma or abuse, that can leave lasting scars. But I think there is certainly a - there are statistical forces. There's definitely pressure that makes one person different from another across the board.

RAZ: Yeah. I mean, when you think about, like, who you are, I mean, do you think you're the same person that you were when you were a child or teenager or in your 20s as you are now?

PINKER: I do see myself as basically the same kind of person. I like the same music. I like the same foods. I like the same pastimes. I have similar kinds of interests. And research on personality shows that there's a substantial amount of continuity in a person's character as they go through life. But there are certain changes that I see in myself that probably occur in most people as they get older.

RAZ: Yeah.

PINKER: We get less neurotic. We get nicer. We get less anxious as we get older, all of us. But still, if one person is more anxious than another at the age of 20, he'll probably be more anxious than the other person at the age of 70 as well, even if both of them are less anxious across the board.

RAZ: So, I mean, if we are more or less the same, right, at 20 or at 70, is it even possible to make big changes to who we are?

PINKER: I think we have the capacity to change our behavior, which is really what counts. I don't think that there's a lot of room to change who we are in the sense of a fundamentally nervous person becoming constitutionally calm and easygoing. But certainly, there are methods of, say, cognitive behavior therapy...

RAZ: Yeah.

PINKER: ...That are provably effective at reducing anxiety and phobias and treating depression.

RAZ: Yeah.

PINKER: And the thing is that those don't appeal to some ethereal, immaterial soul. They are ways of acting on our neural circuitry. We have to keep in mind that our neural circuitry is so intricately complex and has been shaped by evolution to interact with the world through our social mechanisms of interacting - through language, through facial expression, through body language - that there are ways of changing our feelings and thoughts by the old-fashioned route of conversation and example and art and evidence-based psychotherapy. So there is scope for a range of behavior within the envelope of a given personality type. And we can probe the outside of the envelope that the genes make available to us.

RAZ: Do you - when you think about what animates a person, do you think that it can be figured out pretty logically, or do you think that huge parts of it are just mysterious?

PINKER: Huge parts of it are certainly mysterious because the interactions are so unfathomably complex.

RAZ: Yeah.

PINKER: There are 10 to a hundred billion cells in the brain connected by a hundred trillion synapses. And no one can keep track of all of them, even in a computer simulation. We also know that chance plays an enormous role above and beyond the role of either genes or environments. We can see this in identical twins who are brought up together, not the exotic cases of the twins separated at birth, but just the kind of twins that all of us know. If you know a pair of twins, you know that they're more similar than two people plucked off the street at random, but they're unique individuals.

RAZ: Yeah.

PINKER: They're - they - you won't - you don't confuse them when once you know them.

RAZ: And sometimes, they're not friends.

PINKER: And sometimes, they're not friends, indeed. Now, how do you account for those differences? It's not their genes, at least not the ones they inherited from their parents. There could be some - a few mutations that each one idiosyncratically acquired. It's not their - by and large, their environments because they grew up under the same parents, the same school, the same house, the same older sibs, same younger sibs. You're really forced to the conclusion that there's an enormous role for chance, for the roll of the dice in who we become because two people who have everything in common both in the genes and the environmental level nonetheless don't turn out to be indistinguishable.

RAZ: Harvard psychologist Steven Pinker has given several TED talks, including this one about the blank slate. You can find all of them at ted.com. More ideas about What Makes Us Us - that's in just a minute. I'm Guy Raz, and you're listening to the TED Radio Hour from NPR.

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