E.O. WILSON on Cooperation & the Tribal Mind

Wilson: He was, in the 1950s. But recently we were on the Charlie Rose show together, talking about evolution and biology and Darwin, back and forth with a remarkable degree of harmony between the two of us. I’ve always admired him greatly, then and now.

RC: How do you see the two fields—evolutionary biology and molecular biology—collaborating?

Wilson: Intimately, in a number of ways. The molecular biologists base family trees on DNA sequences, and it often requires only a relatively small amount of a genome to say with a high level of confidence which species are closest to one another—that is, which species branched away from each other in evolution most recently. So the tree of life is adding a lot of detail, and it’s also getting a time line. That’s one area nonetheless where evolutionary biologists are essential from the start, because the molecular biologists don’t know the species. But where molecular biology is really taking off on its own is in the exploration of microbial life—bacteria, archaea, and microscopic fungi. These are huge classes of species that can’t be reliably distinguished by ordinary visual examination of body parts. But it’s possible to sequence a complete bacterial genome in as little as four hours. It’s been estimated that as many as 4 million species of bacteria occur in a ton of soil, just a few scoops of a backhoe. The point is that we’re opening the diversity of life at this most basic level. It’s going to be full of surprises.

RC: Surprises that will make a difference?

Wilson: Oh, yes. Just to understand how all these organisms operate in ecosystems will have an enormous impact. Consider the role of nematode worms in maintaining the health and fertility of soils. We don’t know how many nematode species there are. We don’t know what they’re doing. We do know they must be important. Consider this: Four out of every five animals on Earth are nematode worms. What are we to make of that immense biomass about which we understand next to nothing?

RC: But we’re starting to understand it using molecular analysis?

Wilson: I don’t want to give my molecular colleagues too much credit. The genomics approach to identifying nematodes and bacteria is a major breakthrough. They can put names on genomes: “Well, we know X-105BH2 has been found here.” But what does the organism look like? What is its anatomy? Its metabolism? There has to be a uniting of molecular and systematic biology. One deficit caused by the molecular revolution is that we don’t have experts working on all these various groups, on their natural history, their ecology, their behavior. We don’t have the wherewithal to map the biodiversity of the Earth, or even the United States. The systematists, of which I’m one, have built up a very large body of knowledge, and the genomicists are living off that capital. But they are soon going to run out.

RC: Let’s talk about your idea for an encyclopedia of life.

Wilson: Thanks to the Internet and to advances in digital photography, we have the ability to put online superb images of even the smallest organisms. So we can speed up the mapping of world biodiversity by an order of magnitude easily. What we need is an electronic encyclopedia of life, with one page for each species. On each page is given everything known about that species. This should be the driving force for future biodiversity studies; it’s as simple as that.

RC: But it’s not happening?

Wilson: The responses I’ve gotten are so positive, including from molecular biologists, that logic tells me this is about to take off. They want to know what’s out there. Once there’s an encyclopedia of life that they can browse, they will enjoy an almost infinite treasury of important projects to work on. Suppose there’s a snail in Indonesia that produces a powerful fungicide. Well, that might be known by just one elderly guy at Idaho State University who’s a specialist on the snails of Indonesia. But when that species is in the encyclopedia, you can type in “powerful fungicides,” “snails,” “tropical Asia” and . . .

RC: And there it is.

Wilson: You got it. That’s my dream.

RC: One of your other dreams is to see evolutionary biology and the humanities come closer together. How?

Wilson: I’m looking for a congenial meeting. A lot of the suspicion from the social sciences and humanities side is fading, and there are young people coming in who are eager to get what they can from the natural sciences. They don’t feel threatened; they see this as a resource.

RC: In the popular mind, the word Darwinian still often means conflict—fighting over resources—whereas the reality is often adaptation by cooperation.

Wilson: That’s why I wrote the book Sociobiology, about the adaptive value of cooperative behaviors. I wrote a paper with Bert Hölldobler last September that proposes a controversial new model of the origin of social behavior, including cooperative behavior in the insects.

RC: Controversial in what way?

Wilson: I’m taking the idea of kin selection, and I’ve critiqued it. Kin selection is the idea that cooperation arises, especially in the eusocial insects—bees, wasps, ants, termites—because of individuals favoring collateral kin: not just Mom and Dad or your offspring but, just as important, brother, sister, cousin, and so on.

RC: So you cooperate with close kin because it helps get some of your shared genetic heritage into future generations.

Wilson: I found myself moving away from the position I’d taken 30 years ago, which has become the standard theory. What I’ve done is to say that maybe collateral kin selection is not so important. These ants and termites in the early stages of evolution—they can’t recognize kin like that. There’s very little evidence that they’re determining who’s a brother, a sister, a cousin, and so on. They’re not acting to favor collateral kin. The new view that I’m proposing is that it was group selection all along, an idea first roughly formulated by Darwin.

RC: The notion of group selection is heresy, is it not, in the current thinking about evolution?

Wilson: Yes. I’m being provocative again, because this is a radical departure.

RC: The theory is that natural selection works only on individuals, not the social group. Isn’t that the idea of the selfish gene?

Wilson: No, that’s where a lot of biologists mix things up. The unit of selection is a gene, the basic element of heredity. The target of selection is normally the individual who carries an ensemble of genes of certain kinds. But the target can also be the group. How well does that group survive vis-à-vis other groups and vis-à-vis solitary individuals of the same species, and how well does that group produce its own kind? For group selection to happen, all you need is one gene that would cause individuals to come together, and for some of them to be willing to be subordinated and become workers.

RC: But ant workers give up their reproductive futures. Why would they do that, from a Darwinian perspective?

Wilson: That is easy to explain by a feature that we now recognize as universal: the plasticity of expression of single genes. The same gene can produce different body types depending on environmental conditions. The classic case is the arrowleaf plant. If grown on dry ground, it produces an elephant-ear leaf; if grown in a pond, it puts up leaves like lily pads; and if grown in deeper water, it grows up with slender leaves like eelgrass.

So consider a gene that has plasticity such that in one setting an individual carrying that gene becomes reproductive. Maybe this individual was the ant or wasp that arrived first, maybe it was the biggest one, or maybe it was the one to just by accident start laying eggs first. The important thing is that the reproductive role can shift from one colony to the next and from one generation to the next. The group forms, and some individuals by circumstance become workers. Their cooperative behavior and the division of labor confer superiority on that group, with that particular gene, over other groups. It could be as simple as that.

RC: So why isn’t it more common?

Wilson: It only occurs if the environment is extraordinary in some way, producing a resource that is very valuable—like a hollow stem that might serve as a nest site—so that it pays a group with social organization to defend and exploit it. Otherwise, altruism toward fellow group members is discouraged by the Darwinian advantage of surviving and having personal offspring. But once the ants and termites jumped the high barrier that prevents the vast variety of evolving animal groups from becoming fully social, they dominated the world.

RC: Is group selection also why humans are now so dominant?

Wilson: What I’ve done is pose the question. For social insects, I’m presenting as much evidence as I can summon for each of the two opposing views: Either collateral kin selection is the key, or group selection favored by very unusual environments caused them to be altruistic. And I’m pretty sure I’ll continue saying, “I think it’s the latter.” But if you think it’s the former, let’s see better evidence.

RC: For humans this would mean that the tribe was the most important factor in our evolution.

Wilson: Darwin pretty clearly says in The Descent of Man that it’s tribe against tribe—exactly what I’m saying. If this turns out to be the case in the early origin of social behavior in human beings, it might be the best explanation of endemic warfare, which humanity has engaged in since prehistory.

RC: And of endemic altruism?

Wilson: Yes, precisely. The genes that favor this type of group cohesion would also favor an innate sense of morality and group loyalty. It would explain how so often group or tribe loyalty overrides even family loyalty. It would help to explain why, for example, it is the squad or the platoon that men fight and die for, more even than country or religion. So I’m going to be spending time in the future looking into this area, with human behavior as a special case.

RC: Has anyone attacked the idea?

Wilson: No, because I’ve kept it to social insects. But I have respected colleagues working on social insects who think I got it wrong. Right now it’s a work in progress and a trial run.

RC: So you’re not yet riding the flag along the enemy lines?

Wilson: No, I’m not. Not for humans anyway. I might in a couple of years.