Give and Take: Why Helping Others Drives Our Success

by Adam M. Grant

Game theorists call this tit for tat, and it’s a pure matcher strategy: start out cooperating, and stay cooperative unless your counterpart competes. When your counterpart competes, match the behavior by competing too. This is a wildly effective form of matching that has won many game theory tournaments. But tit for tat suffers from “a fatal flaw,” writes Harvard mathematical biologist Martin Nowak, of “not being forgiving enough to stomach the occasional mishap.” Nowak has found that it can be more advantageous to alternate between giving and matching. In generous tit for tat, the rule is “never forget a good turn, but occasionally forgive a bad one.” You start out cooperating and continue cooperating until your counterpart competes. When your counterpart competes, instead of always responding competitively, generous tit for tat usually means competing two thirds of the time, acting cooperatively in response to one of every three defections. “Generous tit for tat can easily wipe out tit for tat and defend itself against being exploited by defectors,” Nowak writes. Generous tit for tat achieves a powerful balance of rewarding giving and discouraging taking, without being overly punitive.