patterned, contextual, and sometimes suboptimal behavior we think of as culture.”13

But game theory has a remarkable resilience against charges of irrelevance. It’s explanatory power has not yet been exhausted, even by the demands of explaining the many versions of human culture. “Surprisingly,” Bednar and Page declare, “game theory is up to the task.”14

The individuals, or agents, within a society may very well possess rational impulses driving them to seek optimum behaviors, Bednar and Page note. But the effort to figure out optimal behaviors in a complicated situation is often considerable. In any given game, a player has to consider not only the payoff of the “best” strategy, but also the cost of calculating the best moves to achieve that payoff. With limited brain power (and everybody’s is), you can’t always afford the cost of calculating the most profitable response.

Even more important, in real life you are never playing only one game. You are in fact engaging in an ensemble of many different games simultaneously, imposing an even greater drain on your brain power. “As a result,” write Bednar and Page, “an agent’s strategy in one game will be dependent upon the full ensemble of games it faces.”

So Alice and Bob (remember them?) may be participating in a whole bunch of other games, requiring more complicated calculations than they needed back in Chapter 2. If they have only one game in common, the overall demand on their calculating powers could be very different. Even if they face identical situations in the one game they play together, their choices might differ, depending on the difficulty of all the other games they are playing at the same time. As Bednar and Page point out, “two agents facing different ensembles of games may choose distinct strategies on games that are common to both ensembles.”

In other words, with limited brain power, and many games to play, the “rational” thing to do is not to calculate pure, ideal game theory predictions for your choices, but to adopt a system of general guidelines for behavior, like the Pirate’s Code in the Johnny

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