What can evolutionary science tell us about human behavior? During the past thirty years, biologists, anthropologists, and psychologists have begun applying Darwinian concepts, such as natural selection and survival of the fittest, to the study of behavior. Are social characteristics, such as aggression, love, and courtship, determined by our evolutionary past and encoded into our genes like physical attributes, such as walking upright or hair color? Are we slaves to our DNA, or does genetic determinism fail to explain fully what it means to be human?
Peter Robinson: Today on Uncommon Knowledge, Evolution and Human Behavior. The comedian, Flip Wilson, used to say the devil made him do it. Now some scientists say our genes do.
Announcer: Funding for this program is provided by the John M. Olin Foundation and the Starr Foundation.
Peter Robinson: Welcome to Uncommon Knowledge. I'm Peter Robinson. Our show today, Evolution and Human Behavior. It was in 1859 that Charles Darwin published On the Origin of Species, outlining his theory of evolution. Attempts were soon made to use evolution to explain not just biology but human behavior. The British philosopher, Herbert Spencer, for example, tried to use the idea of survival of the fittest to justify social and cultural elites. The thinking of Spencer and others like him was widely discredited. But over the last 25 years or so, the idea of using evolution to explain human behavior has been making something of a comeback. Some scientists now argue that all kinds of traits, from aggression to amiability, are encoded in our genes, just as surely as our walking upright or the color of our hair, not, of course, that they put these views forward without controversy. On our show today we'll be examining just what evolutionary science can tell us about human behavior. Joining us, three eminent scientists. Paul Ehrlich is a Professor of Biological Studies at Stanford University. His latest book is entitled Human Natures. Lionel Tiger is a Professor of Anthropology at Rutgers University. His latest book is entitled The Decline of Males. Jeffrey Schloss is Chair of the Biology Department at Westmont College in Santa Barbara. His book is entitled Altruism and Altruistic Love, a topic that, as you'll see, comes up in our conversation.
Title: Darwin's Ghost
Peter Robinson: The journalist, Tom Wolfe, on the Harvard scientist, Edward O. Wilson. "Every human brain," Wilson says, "is born not as a blank tablet, a tabula rasa [?], waiting to be filled in by experience, but as an" - now he's quoting Wilson - "as an exposed negative waiting to be slipped into developer fluid. You can develop the negative well or you can develop it poorly, but either way you are going to get precious little that is not already imprinted on the film." And the film is genetics. Genetics determine not only things such as temperament and levels of aggression, but also many of our most revered moral choices which are not choices at all but tendencies imprinted in the brain. So, the lives that human beings lead are genetically predetermined. Is that so, Lionel?
Lionel Tiger: No. Lives that people lead are genetically influenced, and the trick and the requirement and the obligation of scientists interested in the relationship between biology and behavior is to get right exactly what the relationship is. But determined? No.
Paul Ehrlich: No. You've got to remember, Ed is an old friend of mine - wrote that 25 or so years ago. He might say something different today. Science marches on.
Peter Robinson: Did that position crest a quarter of a century ago?
Paul Ehrlich: I think so. Yeah, it's moved from biologists to people called evolutionary psychologists, who know a lot about psychology and almost nothing about evolution.
Peter Robinson: Jeffrey?
Jeffrey Schloss: No. Nobody buys this, although I would say that the issue isn't just how much do genetics and environment contribute, but underneath that how do they interrelate. How do genetics influence culture and how does culture influence the translation of genetic information?
Peter Robinson: Okay, so none of you buys E. O. Wilson?
Lionel Tiger: No. The fact is you cannot - and I forget who said it first - you cannot have an organism without an environment, and you cannot have an environment without organisms.
Paul Ehrlich: Gene environment is an interaction. The whole innate nature/nurture is a false dichotomy.
Lionel Tiger: It's a false dichotomy, and what has happened is that people on both sides of this false dichotomy have taken false positions. On the one hand, the people that oppose the biological approach, saying, well, you're all a bunch of determinists and ending up and saying, you're all fascists in some sense or another. And then the other side - there's a group saying, well, you people are Luddites, know-nothings and you have no idea at all what's going on in biology.
Paul Ehrlich: Skip the politics. I mean, all you have to say to know that genetics influences what we do is that we're sight animals. We're sight animals because we originally, many millions of years ago, lived in the trees. That's one of the reasons we pay so much attention to trivial characters like skin color. So, genetics influences all kinds of things that we do. What it doesn't influence is can I marry a woman who has an income of at least $100,000? People aren't genetically programmed to do that sort of thing, but the fact that we're sight animals, that we have sex drives, maybe that we pay a lot of attention to our relatives, is undoubtedly partly due to our genes, but it depends on the environment.
Peter Robinson: Okay, everybody agrees with that statement?
Lionel Tiger: No, just one second. There is a human nature. I think here Paul and I will disagree. There is a human nature. It would be unrealistic for there not to be. There's an English economist who said that the most reckless theorist is he who presumes to let the facts speak for themselves. And a lot of people have simply assumed that the facts speak for themselves and there's no human nature, because there're so many variations. But they're variations with respect to a central tendency, and it's the central tendency that's interesting.
Jeffrey Schloss: The question that Paul just raised and suggested there wasn't a genetic answer to the question - well, there may be a genetic inducement to asking the question. I mean, people don't mate randomly with respect to income, although the correlation, connection may not be genetic.
Paul Ehrlich: The issue really is why. And I agree that the question really is what is the central tendency. My basic answer would be that the central tendency is that we are very, very smart primates, and that is partly due to our genes, and that probably also...
Peter Robinson: Let me ask Lionel if he agrees with Paul's statement on our central tendency.
Title: What is the Tendency, Lionel?
Peter Robinson: Very, very smart primates. Will that do, for you?
Lionel Tiger: No, because we've done some exceptionally stupid things. Let's set aside war for the moment, but in 1971 Robin Fox and I published a book, The Imperial Army it was called, in which we made, to us, the very innocent point that babies, newborns, should not be taken away from their mother and put into a ward of other neonates while the mothers are off on their own in their private room, wondering where's their baby.
Peter Robinson: And on what grounds did you make that argument?
Lionel Tiger: Because if you look at the nature of mammalian and higher primate bonding relationships, you see that these connections are very early formed and they're very important for both members of the duet. [overlapping voices]
Peter Robinson: For a moment or two, I just want to let him run, just to find out how a sociobiologist thinks. So, you took observations from the primate world, from chimpanzees or mammals of all kinds and applied them to human beings and came up with a prescription.
Lionel Tiger: Right. The outcry we had from people saying, oh, well you know, this is just biological determinism, and so on. Nonsense. Well, in fact, now the norm is that mothers and infants are kept together, but had we started off with the notion of human nature we would never have separated them in the first place. And this is my concern here.
Peter Robinson: That pattern of thinking, observing characteristics in the mammal world, and then looking at instances of behavior in the human world, and saying, well, because we see this in the mammal world, we really ought to be doing this in the human world - that strikes you as valid?
Jeffrey Schloss: Well, I don't think that's what he's doing. I think just because we see something in the world of mammals, we don't necessarily assume that we should see it in the world of humans. But then the question...
Peter Robinson: You took an argument and you based it at least in part - a large part, as I - isn't that what you just said? - on mammal behavior.
Lionel Tiger: But also cross culturally, because in no other human society than our [overlap]...
Peter Robinson: Including...?
Lionel Tiger: Yes, human cultural variation is a sign of our biology.
Jeffrey Schloss: But even on that topic there's a bolus [?] of empirical data on maternal deprivation in both primates and humans, so it wasn't simply a non-empirical extrapolation.
Peter Robinson: Well, I think I detect a little queasiness on your part in lumping humans in with chimpanzees and gorillas. That makes you queasy, or no?
Jeffrey Schloss: No.
Paul Ehrlich: [overlap] bit queasy. What's so interesting is there's so damn little difference genetically between us and the - a really interesting, fascinating question, which we'll start getting a small answer to when they sequence the chimp genome, is how we get the incredible differences, for example in our neuromuscular system that allows us to make stone tools, to throw accurately, to have our tongues whip around in our mouths at an incredible rate - those, plus getting a great big brain, losing a lot of facial hair. There's tiny, little genetic differences between us and chimps. I mean, we're really in there.
Peter Robinson: Let me press just a little on whether the case for a genetic basis for human behavior is good science or just an interesting theory.
Title: Weird Science?
Peter Robinson: Richard Lewontin at Harvard - tense relationship between Lewontin and Wilson, who at one point were inhabiting the same building and evidently didn't speak to each other in the elevator. Lewontin says, wait a minute, talking about the genetic basis for human behavior is at a very minimum bad science - not a single genetic basis. The gene for no behavior whatsoever has ever been identified. All of this is extrapolation from evolution, which is in itself a theory that fits a lot of data but that doesn't fit all data. This is not based on physical science. What do you make of that?
Jeffrey Schloss: Well, not a single gene for primate behavior has ever been found either. So, I think that's a red herring. The question is first of all, can we think of scenaria in which genes would and ought to influence behavior, arguing that...
Peter Robinson: So, Lewontin would say no gene for aggression has been found.
Lionel Tiger: Well, no...
Paul Ehrlich: [overlap] would predict one.
Lionel Tiger: His mistake is to say gene behavior, one to one. There is no such event that you can get in nature. Nature's a set of statistical tendencies. And for Lewontin to say that there's no relationship between the genotype and the behavior of the genotype is preposterous, actually.
Paul Ehrlich: I think both Dick and Ed, both of whom are friends of mine, and that's sometimes a difficult situation, are somewhat misrepresented here. Dick would, for example, immediately admit that if you got trisomy, the sort of thing that leads to the so-called Down Syndrome...
Peter Robinson: Medical conditions, yes, but he draws the distinction between medical conditions - physical outcomes from [overlap] and behavior.
Paul Ehrlich: What he's basically trying to say, I think, is we don't understand how genes are transformed entirely into the structure of the brain and the hormones that bathe it, which determine our behavior, and we don't understand how that structure is determined into behavior, so that sitting around assuming that virtually anything that might or might not affect our fitness has got a genetic component in it is bad science. But that doesn't mean the general...
Peter Robinson: Let me do this then. We've now dismissed E. O. Wilson. But let me ask you this, Lionel. Can you give me then a succinct statement of the distinctive insight of sociobiology? Why is the sum total of human knowledge greater today, now that sociobiology has emerged as a discipline, than it was before?
Lionel Tiger: Let me make a...
Peter Robinson: A succinct statement. What does it stand for? What does it tell us?
Lionel Tiger: Okay. Let me take a case, a practical case. Nine-tenths of the victims of Ritalin given in schools are boys. Okay?
Peter Robinson: Victims of Ritalin?
Lionel Tiger: Yes, victims of Ritalin. That is, their behavior has been chemically modified because they don't suit the school system as it defines itself.
Peter Robinson: The pretext, to take your point of view, is that they have Attention Deficit Disorder. Is that right? ADD, and they're given Ritalin.
Lionel Tiger: Right. Certainly discovered when the drug was discovered. But the point is that here we have a massive intervention in the behavior of organisms that we're paying for, that are our children, based on the fact that males and females differ. And this is not a genotype issue, per se, but males have much more physical activity, they don't like to sit still throughout the primates. Look at me. Their behavior is much more vigorous, socially, and they end up seeming to have an Attention Deficit Disorder, so-called. Well, we have taken an artificial means, which is a drug, and drugged them into the behavioral syndrome more appropriate to what the school systems like, which is the behavior of girls who do better in the school system. Now anyone who understands comparative biology would say you're going to expect a real difference between boys and girls. So, if to expect them to act the same is simply bad science, and even worse, very bad social policy.
Peter Robinson: So, the insight - let me take a stab at it then. The insight then is that nature in itself is extremely powerful, and you can waste a lot of time and do people damage by refusing to accept certain aspects of our nature as simply given. Is that a fair statement?
Lionel Tiger: It's our starting point. And if we don't start with what is our best guess about what nature is, then we're living in the world of the pure environmentalists, which were the social activists that animated communism, for example.
Peter Robinson: A new topic for Jeffrey. Why is altruism so important in understanding human behavior?
Title: Brothers' Keepers
Peter Robinson: E. O. Wilson has described biological altruism as sacrificing of an organism's reproductive success for that of another as "the central theoretical problem in comprehensively explaining social behavior in the light of natural selection." Why is altruism the central theoretical problem?
Jeffrey Schloss: Well, first of all, you have to distinguish what he means by altruism. He's not talking about motivationally unselfish feelings. He's talking about consequentially sacrificial behaviors. And Darwin himself said that any characteristic that exists for the exclusive benefit of another would "anniliate [?] my theory." So, Wilson is simply acknowledging that in any organism, not just human beings - plants - a characteristic which increases the fitness or reproductive success of another at the expense of its own couldn't be established by natural selection, and if it came about by some other means would be eliminated by natural selection.
Peter Robinson: Okay, so it's the central problem because it's aimed at the very basis of natural selection.
Jeffrey Schloss: If it exists.
Peter Robinson: All the way back to Darwin.
Paul Ehrlich: But I mean, this is now sort of a red herring. There're all kinds of mechanisms that are known, like kin selection in which your identical genes, in a sense, are passed on by your relatives...
Jeffrey Schloss: But kin selection doesn't explain the existence...
Peter Robinson: Describe the term kin selection.
Jeffrey Schloss: Kin selection is making a sacrifice for someone who shares a genetic similarity with you.
Peter Robinson: [overlap] who sacrifices - who throws herself in front of a car to save her children.
Jeffrey Schloss: Actually that's a good point...
Paul Ehrlich: Or brother.
Jeffrey Schloss: No, actually not. Brother, yes, but the genius of kin selection - and I like another term better, inclusive fitness. Darwin's notion of fitness was that reckon [?] fitness in direct offspring, so a mother who sacrifices for her children - that actually wouldn't be kin selection - that's her offspring. But J. B. S. Alldane [?] was doodling on a napkin in a pub one night, and he said, "I'll gladly give my life for two brothers or four cousins." And actually, he miscalculated. It should have been eight cousins. But see, that's kin selection because those aren't his offspring. And yet, a proportion of his genome makes it into the next generation by risking for them.
Paul Ehrlich: But culture changes all of us so much, and I think the best example of this is in this very area. One message that, in some sense, has to be coded into our genes and expressed in almost any environment is out-reproduce your buddies, otherwise we never would've gotten here. Right? And let me tell you, how many people in the audience - how many women do you think have had 20 or more children? Quite capable today, but culturally we have found out, and from a long time ago, that we can interrupt that message from our selfish genes, if you will. In Egypt women used crocodile dung suppositories to limit their families. We don't know exactly how effective they were, but I suspect they were pretty effective. Today you could easily support many more children. You can optimize your reproduction. The average in France is now 1.2 children per family. They can easily raise 10.
Lionel Tiger: They can't optimize it because the social requirements of having a child are now so severe, including orthodontia and ballet lessons, that no parent could deal with more than 2 or 3 children at a time.
Peter Robinson: Do we have free will or do we not? Does sociobiology have an answer to this eternal philosophical question?
Title: Freedom's Just Another Word
Peter Robinson: Tom Wolfe once again - "What makes you think you have free will? I have heard neuroscientists theorize that given computers of sufficient power and sophistication, it would be possible to predict the course of any human being's life moment by moment." Lionel?
Lionel Tiger: Well, he's a novelist, if he can control all the events of his novels, but you can't make that statement about people. You can, however, say that...
Peter Robinson: Even in principle, you can't?
Lionel Tiger: No. Certainly not - you wouldn't want to, in principle, because then the relationship between the environment and the organism would not be biologically pertinent. You want the flexibility.
Peter Robinson: Hold on. What I'm after here is the notion of free will. I grant you the organism, I grant you the environment that the organism is in. But hold on a minute. If you knew enough about the environment, and you knew enough about the organism, and you had a big enough computer, you could plug it all in, because you haven't mentioned the capacity for free, unconstrained choice.
Lionel Tiger: When Isaac Singer won a Nobel Prize for literature, he was interviewed by the New York Times, and there was this whole, long interview, and at the end the journalist said, "Mr. Singer, do you believe in free will?" He said, "Do I believe in free will? Of course. I have no choice."
Paul Ehrlich: Listen, it's really a red herring.
Peter Robinson: But wait a minute. You're conscious that it's an issue because you write that you believe that human beings have a form of free will. Now why that qualifier, Paul?
Paul Ehrlich: A form of free will because it depends on what philosophic position you take, but for practical purposes we have free will, we make choices. It doesn't mean our choices aren't influenced by both our environment and by the DNA that's stored in our bodies. But we basically have free will.
Peter Robinson: Okay. But you, who are solving all kinds of problems, reaching down the evolutionary chain millions and millions of years, take this question and just dodge it, and say, oh, it's uninteresting - it's a practical matter, we have free will, let's move to the next question. But that strikes me as [overlap]...
Paul Ehrlich: It's like the Heisenberg uncertainty principle. You know, you think you could know the position and movement of an elementary particle at the same time, but it turns out it's just impossible, so why worry about it?
Jeffrey Schloss: Inability to predict something is not the same thing as autonomous agency.
Peter Robinson: Autonomous agency. There. We've now moved to - free will, I think is causing trouble because it suggests the Judeo-Christian tradition. Let's call it autonomous agency. Let's call it a question of self. Do you believe that there is, independent of this set of meat and chemicals, and independent of this environment, a self that somehow organizes and is capable of autonomous agency? Do you believe that?
Lionel Tiger: Well, of course [overlap]...
Peter Robinson: Paul, you said not independently. That is to say that once this bag of meat and chemicals is dead, any self dies with it.
Paul Ehrlich: Well, once can say anything one wants about that. My belief is yes, that after I'm dead it'll be exactly like it was before I was born. But there's no way I can dem - that's not a scientific issue. There's nothing you can say about it.
Peter Robinson: So, you're not rejecting the notion of a soul.
Paul Ehrlich: Oh, I personally reject it totally.
Peter Robinson: You personally reject it, but as a scientist?
Paul Ehrlich: As a scientist, I can't.
Peter Robinson: You're not rejecting it, you're simply saying, I don't have the equipment to deal with the question. Is that the point?
Lionel Tiger: No, I reject it as a scientist, simply because the verifiable evidence is extremely poverty stricken. And the kinds of claims that have been made for the soul, per se, are sufficiently bizarre and often cause sufficiently tragic human circumstances, such as religious wars and the like for me to be very suspicious of people saying, well, you can't prove it doesn't exist, therefore it might exist. This seems to me essentially a misdemeanor or a [overlap].
Paul Ehrlich: I'm also not a neutralist on Jack Frost. I mean, I agree with that. I just don't think that it's something science is in a position to deal with in the normal way that science does.
Lionel Tiger: Well, what can science do? If it can't say, I'm sorry that the unknowable is knowable potentially...
Peter Robinson: So, you two who have been making light of Tom Wolfe through this whole discussion would, however, agree with the title that Wolfe gave this essay, which is, "Sorry, but your soul just died." The findings of sociobiology militate against any notion of a soul.
Jeffrey Schloss: I disagree. I mean, any scientific explanation has to start with looking at naturalistic causes, so in order to do evolutionary psychology or behavioral psychology [?] can't invoke a soul, and we're all willing to play by those rules. But the findings don't make it either illegitimate or unlikely. Culture is just another form of determinism without autonomy, and once we have autonomy then we ask the philosophical question, where does it come from.
Peter Robinson: So, this is a general disa - what we've attempted to solve [overlap]...
Paul Ehrlich: [overlap] disagreement in this sense. To me, it's crystal clear where religion came from. In other words, the track is - I mean, me and most other mammals, as far as we can tell, have cause and effect built into our brains. When you get smart enough and you see effects you don't know the causes of, you start inventing them, and so you have spirits that move the rocks, and so on and so forth. And so, then you get people that...
Peter Robinson: Inventing explanations for effects we don't know the causes of. But wait just a minute. Isn't sociobiology guilty of just the same thing?
Title: Truths or Consequences
Peter Robinson: Let me hit you with the great dictum of Carl Popper, which is that a scientific theory to be taken seriously must be falsifiable. Given evolution, three very bright minds at this table can come up with one problem after another and figure out ways in which human behavior plausibly fits with natural selection. But not only can you not prove it, you can't even state it in a way in which it can be subjected to experimentation in which it could be proven true or false. What do you make of that one?
Jeffrey Schloss: I think that's a real problem, but I think you're overstating it. For example, back to the notion of kin selection. There's a prediction there. The prediction there is that investment will be made in others to the proportion of genetic relatedness. So, in fact, Robert Triver [?] led some fascinating experiments looking at the provisionary behavior in social insects and found that to be exactly the case. And we could make similar predictions in human societies.
Paul Ehrlich: Oh, by the way, Popper is fading a little bit. Cultural evolution goes on in science too, and popularly Thomas Kuhn and Popper, both very bright guys, had interesting ideas, which now philosophers of science are beginning to think probably weren't quite as solid as they thought they were. People now think that you can accumulate evidence and that rejection is not the only way to deal with a hypothesis.
Peter Robinson: But if you're not saying, wait a minute, my science is based on physical evidence and experimentation, and is open to falsifiability, then really, you leave the door open to kind of metaphysical discussions about natural - would they behave this way because of what happened a hundred million years ago? And what's...?
Paul Ehrlich: Is cosmology not science?
Peter Robinson: What's difference from metaphysicians five hundred years ago talking about how many angels can dance on the head of a pin?
Paul Ehrlich: I can tell you what's different.
Lionel Tiger: Well, what's different is the genome. For example, we now know that it isn't just a bunch of angels on the head of a pin. We know it's a bunch of things going on inside of the genetic system. So, we have a location finally for our stance in the world.
Paul Ehrlich: What makes science different from all these other things is A, it's an adversary system. We can sit here, three guys who basically are interested in the same thing, and we can openly disagree with each other, and we will, and if we can show the others - and without getting into a personal battle. And the second thing is, nature's there is the final arbiter.
Jeffrey Schloss: You're so right. And you're asking the question, how is nature serving as an arbiter in these issues. And that's a legitimate question.
Peter Robinson: Last question. I'm going to go to Tom Wolfe once again and ask you to make a prediction. Here's Wolfe: "This sudden switch from a belief in nurture in the form of social conditioning to nature in the form of genetics and brain physiology is the great intellectual event of the 20th century." Twenty-five years from now, will it be seen as the great intellectual event of the 20th century? Paul?
Paul Ehrlich: No.
Jeffrey Schloss: Only insofar as it gave rise to focusing on developmental issues.
Lionel Tiger: Yes, in the sense that just as Marx was the thinker that animated most of the intellectual work of the 20th century, I think Darwin will be the thinker who animates most of the intellectual work of the 21st century. They were both highly systematic thinkers. Marx unfortunately didn't have a unit of measurement the biologists do, which is the gene.
Peter Robinson: [overlap] Why not?
Paul Ehrlich: We're going to take an evolutionary approach to things, and maybe the great intellectual step will be when we look at our non-genetic information and how it evolves. When we understand the evolution of our non-genetic information of our culture as well as we understand the evolution of our genetic information, that will be the greatest step.
Peter Robinson: Jeff Schloss, Paul Ehrlich, Lionel Tiger, thank you very much.
Peter Robinson: Lionel Tiger argued that the intellectual legacy of Charles Darwin will loom as large over the 21st century as that of Karl Marx loomed over the 20th. If so, what will the implications be for our politics and our law. Join us next week as we continue this discussion with Paul Ehrlich, Jeffrey Schloss and Lionel Tiger. I'm Peter Robinson. Thanks for joining us.