Game theory studies how we maximize gain in competitive situations, assuming that self-interest controls why people make decisions. In Rock, Paper, Scissors, physicist Len Fisher starts by demonstrating the limits of game theory: What’s best for you isn’t always what’s best for everyone else, and that discrepancy can ultimately undermine your own self-interest. For instance, it may be easier for you to spit gum on the sidewalk than throw it in the trash, but if everyone did that, all our shoes would be sticky.
The good news is that human beings are much more cooperative than some of us might assume. Fisher uses game theory to show how cooperative behaviors have evolved to escape the traps created by selfishness, and how cooperation persists even in the most difficult circumstances.
For models of real-life solutions, Fisher looks to various games. For example, the game “I Cut and You Choose” exploits self-interest in order to create cooperation: When slicing a cake, one person cuts two pieces, then the other person chooses the piece they want for themselves. Assuming the cutter likes cake, she has incentive to make both pieces equal. Fisher suggests employing the same strategy to solve territorial disputes between countries.
As one might expect, many of Fisher’s game-theory solutions seem a trifle abstract and idealistic: What happens when three people want cake? Even so, Rock, Paper Scissors is a wonderfully entertaining introduction to game theory and the science of cooperation.