Once a consensus is reached on what happened, scientific inquiry can proceed in a more unified fashion than before. I end this series with a summary of what a fully reconciled field of sociobiology will look like. For a more detailed account, please consult my 2007 article co-authored with E.O. Wilson titled "Rethinking the Theoretical Foundation of Sociobiology".

The plenary speaker is Hanna Kokko, a theoretical biologist from Finland who has risen to the top of her field. I just turned 60 and Hanna seems awfully young to be giving plenary talks, but anyone who worries about women in science should see her lead the huge audience through her theoretical models on diverse ecological and evolutionary topics.

Hanna's first two examples illustrate the fact that evolution at a local scale can be maladaptive at a larger scale and can even lead to extinction. In the first example, a species of fish in which the females are asexual but still need to mate with males of a sexual species for their eggs to develop outcompetes the sexual species and therefore drives itself locally extinct. In the second example, an endangered bird species on a small island evolves large territory sizes, reducing its population size and increasing its chances of extinction. If local evolution favors traits that are so detrimental over the long term, how can more sustainable traits evolve? When Hanna mentions group selection as a possibility, she shows this image of a man so panicked that he's about to jump out the window (thanks to Hanna for providing me the image).

Lynn is famous so you might already know her story. In the 1970's she proposed the radical theory that nucleated (eukaryotic) cells evolved not by small mutational steps from bacterial (prokaryotic) cells, but as symbiotic communities of bacteria that became so integrated that the group became a higher-level organism. She was fiercely opposed but carried the day, an accomplishment so great that she was admitted into the National Academy of Sciences in 1983.

The concept of organism as group was generalized in the 1990's by John Maynard Smith and Eors Szathmary in two books titled The Major Transitions of Evolution and The Origins of Life: From the Birth of Life to the Origins of Language. Their theory was multilevel selection theory with a twist. The evolution of group-level adaptations requires a process of group-level selection and is undermined by selection within groups. Now for the twist: The balance between levels of selection is not static but can itself evolve. When between-group selection sufficiently dominates within-group selection, the group becomes a super-organism and the lower-level organisms acquire the status of organs. The evolution of nucleated cells was just one of many major transitions, preceded by the evolution of the first cells and possibly even the origin of life itself as groups of cooperating molecular interactions, and followed by the evolution of multicellular organisms, social insect colonies, and--as we shall see--human social groups.

I will focus on one of many examples that can be provided. In 1995, Robert Heinsohn and Craig Packer published an important paper on territorial defense in lions in the journal Science. As good experimental field biologists, they had played recordings of lions from neighboring territories to observe how females of the focal territory responded. They discovered that the same individuals consistently arrived first at the scene while others consistently lagged behind. There seemed to be bravehearts and cowardly lions within the same pride.

Readers who have been following my "Truth and Reconciliation for Group Selection" series will be well prepared to appreciate the import of the Science article. Group selection requires variation among groups. Variation among groups is eroded by dispersal. Therefore, group selection can only take place in groups that are highly isolated from each other. That is part of the reasoning the led to the conclusion that group selection can only take place under highly restrictive conditions.

But wait. This argument assumes that dispersal is random. What if dispersal is conditional? What if individuals stay in groups when they are sufficiently cooperative but leave when they become overrun by selfish individuals? In this case, dispersal might increase variation among groups, improving the conditions for group selection. John Pepper and Athena Aktipis (featured in T&R XII) are two theorists who have studied this "walk away" process in agent-based simulation models.

How would group selection be tested in the laboratory? Let's begin with the thousands of selection experiments that have already been conducted in the laboratory at the individual level. A population of animals, such as fruit flies or chickens, is measured for a particular trait, such as bristle number or egg productivity. Individuals that score high or low (depending upon the desired direction of selection) for the trait are selected to breed the next generation. If the average value of the trait in the offspring generation shifts in the direction of selection, then the trait is heritable and there has been a response to selection. Over many generations, artificial selection can cause organisms to become completely different from their ancestors, as our domesticated plants and animals attest.

Group selection can be studied in the laboratory by a simple extension of the protocol outlined above. A population of groups is created, a particular trait is measured for the groups, and the highest (or lowest) scoring groups are used to breed the next generation. If the average value of the trait in the offspring generation shifts in the direction of selection, then group selection is proven to be efficacious, at least under the conditions of the laboratory experiment.

Such was the fate of William D. Hamilton, the legendary founder of inclusive fitness theory, which was dubbed kin selection by John Maynard Smith (see T&R VIII). Hamilton became world famous for explaining how altruism can evolve according to the rule br - c >0, where b is the benefit that the altruist gives a recipient, c is the cost to the altruist, and r is the chance that the recipient shares the same altruistic gene through a common ancestor. At least that was the original interpretation of r; eventually it morphed into something different, as we shall see.

Each student is given a wooden stick with an A (for Altruistic) or S (for Selfish) written on one end. Information on the blackboard tells them that altruists give three fitness units to their partners at a cost of one fitness unit to themselves. Selfish individuals receive without giving. Then they are instructed to move around the room and find a partner at random without revealing their identities. At the count of three, they reveal who they are and write their gains and losses on a 3x5 card. After repeating the process of pair formation and social interaction several times, the students total their score and take their seats for a few minutes of instruction.

This book will show how both individual selfishness and individual altruism are explained by the fundamental law that I am calling gene selfishness. But first I must deal with a particular erroneous explanation for altruism, because it is widely known, and even widely taught in schools. This explanation is based on the misconception that I have already mentioned, that living creatures evolve to do things 'for the good of the species' or 'for the good of the group'.

There's the caution against naïve group selectionism. Good for you, Richard! Now for the explanation of why it is naïve:

Another form of naivete is just as common but less well publicized--the unquestioning belief that natural selection operates at the level of the gene and that this constitutes an argument against group selection. Call it naïve gene selectionism.

Blustery statements like these have a bad smell about them. In truth, the models that led to the rejection of group selection were little more than sketches on the backs of napkins. Models supporting the plausibility of group selection began to appear as early as the 1970's, but that did not stop the patriotic propaganda machine from rolling onward.

Did I clean it up? Of course I did. Anyone would.

Here's another example of a mess: Imagine a man who has made a mess of his life. He has taken advantage of those who loved him and piled lies upon lies until he can't keep them straight anymore. Now he has been abandoned and has only himself to blame. If only he could go back to the beginning!

Should this man clean up his mess? Of course he should, and would be much better off if he did, but we wouldn't be surprised if he didn't. It would require great courage. Twelve-step programs are designed for people like him and include acknowledging one's faults and apologizing to others.

Here's a third example of a mess: Imagine that an entire scientific community has made a decision that turns out to be a mistake. The decision was momentous. It was regarded as a watershed event for the field. Its architects were celebrated as heroes. It was enshrined in textbooks. Nevertheless, subsequent events had proven it to be incorrect. If the current information was known back then, a different decision would have been made and the entire field would have taken a different path.

Should the field clean up its mess? It should, but the likelihood that it will is even less than for the individual who messed up his life. After all, "the field" is not even a corporate unit capable of making a decision like an individual. Instead of a collective decision, a cacophony of responses can be expected, including acceptance, denial, and halfway positions that attempt to acknowledge change while still clinging to the patriotic history.

That is what has happened with the group selection controversy. The categorical rejection of group selection in the 1960's was wrong, plain and simple. If they knew then what we know now, it would never have happened. Some evolutionists are perfectly comfortable with this conclusion. Others act as if nothing has changed since the 1960's. Others say that the original rejection of group selection remains valid and what passes for group selection today is different. Others claim that group selection and its alternatives are equivalent, making it a matter of preference which to employ. Others construct models and perform experiments that anyone would have identified as group selection in the 1960's, but just don't use the G-word. In short, the field as a whole is a big mess.

What is the water of our culture? I would like to nominate individualism. Individualism is the belief that individuals are somehow a privileged level of the biological hierarchy; that explanations framed in terms of individual action are somehow more "fundamental" than explanations framed in terms of social action; that individual self-interest is a grand explanatory principle that can explain all aspects of humanity. For many people, these beliefs seem like common sense. Water always does.