When the experimenters complicated things—by throwing bread chunks of different sizes—the ducks needed to consider both the rate of tossing and the amount of bread per toss. Even then, the ducks eventually sorted themselves into the group sizes that Nash equilibrium required, although it took a little longer.1
Now you have to admit, that’s a little strange. Game theory was designed to describe how “rational” humans would maximize their utility. And now it turns out you don’t need to be rational, or even human.2 The duck experiment shows, I think, that there’s more to game theory than meets the eye. Game theory is not just a clever way to figure out how to play poker. Game theory captures something about how the world works.
At least the biological world. And it was in fact the realization that game theory describes biology that gave it its first major scientific successes. Game theory, it turns out, captures many features of biological evolution. Many experts believe that it explains the mystery of human cooperation, how civilization itself could emerge from individuals observing the laws of the jungle. And it even seems to help explain the origin of language, including why people like to gossip.
I learned about evolution and game theory by visiting the Institute of Advanced Study in Princeton, home of von Neumann during game theory’s infancy. Long recognized as one of the world’s premier centers for math and physics, the institute had been slow to acknowledge the ascent of biology in the hierarchy of scientific disciplines. By the late 1990s, though, the institute had decided to plunge into the 21st century a little early by initiating a program in theoretical biology.
Just as the newborn institute had reached across the Atlantic to bring von Neumann, Einstein, and others to America, it recruited a director for its biology program from Europe—Martin Nowak, an Austrian working at the University of Oxford in England. Nowak was an accomplished mathematical biologist who had mixed bio-