Can you give an example of such overinterpretation?
I recently had the opportunity to visit an endangered species called the red-cockaded woodpecker in Florida. This is the only species in the world that drills nests in live trees. Why do these birds drill in live trees? Because when they enter the tree it exudes large amounts of sticky sap all around the entrance hole. The birds can fly in and out, but their principal predator, the rat snake, is prevented from entering by this sticky mess. Now, finding the right kind of tree and drilling the hole takes a long time, as much as a year, for a young male red-cockaded woodpecker. It is to his advantage to stay with his parents and help them out while he is doing that. Maybe there is some kin selection going there, but that’s not what’s causing the behavior of staying at home and helping. When the young male completes his hole, he courts a female, they move in, and they start a nest there of their own. That is the incentive that keeps him there.
How would you interpret this behavior within your new framework?
The alternative hypothesis is that it is to the advantage of kids to stay at home until they can find a place to go. This
is called the “anticipation of inheritance.” If Mom or Dad dies, you’ve got their nest and their territory. If they don’t, you stay, and it’s to your advantage to help, and it’s to their advantage to have your help until
you can get a territory of your own. Basic natural selection explains it; no kin selection required.
Seen that way, it is difficult to understand why anyone attributed this kind of behavior to kin selection in the
That’s what I point out in our Nature critique. Researchers have gone at it backward. Instead of studying what’s going on and seeking the best explanation, they start by looking for a test to demonstrate it’s really kin selection.
What about the classic kin-selection example, worker bees sacrificing themselves for their queen? How else can you explain that?
The best way to think of what has been called altruism in social insects is to return to an individual level of selection: that is, queen to queen. Think of the workers as robots and near-replicants of the queen herself. From the beginning these subordinate replicants are just extensions of the queen. It really is queen against queen, since they are the only ones that produce offspring.
But whether or not bees are altruistic, altruism certainly exists in humans. Humans are different because we seem to have true multilevel selection (pdf). On one level, individual selection goes on inside groups, with people competing against each other and producing what we think of as selfish behavior. On another level, selection goes on between groups. Group selection tends to reinforce altruistic behavior in individuals because without altruistic individuals, the group is at a disadvantage in competition and combat with other groups. But that is not kin selection.
It seems as if kin selection could actually damage the group. For instance, nepotism weakens a group, doesn’t it?
n the level of the group, nepotism is counter-evolutionary. A group of altruists will beat a society of selfish individuals every time. Group selection favors biological traits like communication and cooperation that are needed for the group to remain cohesive and powerful. In humans, there’s a constant struggle between group selection and individual selection that is unique. Humans managed to find a way to strike a balance. It took a lot of intelligence, but that is a story for another day.
From an evolutionary perspective, then, does kinship matter at all in humans?
You can have kin selection incidentally. You can certainly increase your genes by giving up your job and your marriage and taking care of your sister’s kids. If you did it very well, that could result in an increase in your genes. But my point is that it doesn’t lead anywhere in terms of evolution. Inclusive fitness theory said that social behavior advances because kin find one another and bond together to spread their genes, and then a society emerges. But I’m afraid it’s the other way around. When people bond together, kin or not, they can become competitive as a group.
Despite all this, your colleagues are digging in and defending kin selection with passion. How do you respond?
It’s gonna be a battle royal—and not pretty. You might know Schopenhauer’s three stages of response to a new idea. The three are one, ridicule, and I’ve been through that already. Two, outrage. And three, the declaration that it’s obvious.
You seem to be passing through stage two right now.
One letter to Nature is signed by 144 people. Their argument has been around for four decades, but nothing in the letter addresses the challenges we raised: that the mathematical ground of inclusive fitness theory is unsound and that, when you compare competing hypotheses, outcomes are much more directly and convincingly explained by mainstream natural selection.
But for now it seems like the bulk of scientific opinion is against you.
Science is not done by polling. Have you ever heard of “100 Scientists Against Einstein?” It was a pamphlet signed by 100 physicists to overthrow his theory of relativity. After they published it, Einstein remarked, “Why 100 authors? If I were wrong, then one would have been enough!”
Your new take on evolutionary theory seems to echo an older view of human nature: more about competition, less about compassion. Do you agree?
If you look at the humanities and much of the creative arts—especially the dramatic stories of war, alliance, and love—many literary themes describe the conflict between group and individual selection. When we look at human evolution in this new way, it’s going to be much more productive. We now have solid grounding for explaining our social behaviors in terms of the multiple levels of selection that actually occur.