Without further ado, here is Lin Ostrom's recipe for success, taken from the final chapter of her book Understanding Institutional Diversity.

Lin (as she likes to be called) is a political scientist by training, but the study of institutional change is central to the field of political science, even if the E-word is sparsely used. She felt impelled to use the E-word in the title of her 1990 classic Governing the Commons: The Evolution of Institutions for Collective Action and liberally cites the evolutionary literature in her more recent Understanding Institutional Diversity (2005).

Norms? Economists have been the primary advisors on public policy and they're only newly considering a little thing called norms? This is the kind of disconnect between economic theory and reality that makes outsiders rub their eyes in disbelief.

Yet, it is important to resist the facile conclusion that economists are delusional as individuals. Most economists are very smart, very well informed, and very well-intentioned for the most part. We therefore have a mystery to solve that is far more interesting and consequential than mocking economists: What are the social and intellectual dynamics that cause smart, well-informed, and well-intentioned people to ignore something as manifestly important for our species as norms?

The Allais Paradox provides a nice way to begin understanding the gap between economics and evolution. Using the notation that I introduced in E&E I, if A=the assumption that people maximize their mean expected utility and A'=the assumption that people are also sensitive to the variance in addition to the mean, then A' is clearly superior to A as a description of our species. Call it evolution, psychology, common sense, or whatever you like. If core economic theory is a collection of assumptions (ABC), and if science is an incremental process, then the transition from ABC to A'BC should be straightforward. What Allais established would be progress, not a paradox. Instead, something about A' made A'BC more problematic than ABC, interfering with incremental scientific progress. What was it?

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.