CDC, AMANDA MILLS
In his book The Selfish Gene, Richard Dawkins devises a population of birds to explain reciprocal altruism. In this population, there is a deadly disease that is spread by ticks. The birds can groom themselves to remove ticks, and thus protect themselves from disease, in all but one spot—the top of the head. On that spot, they must rely on other birds to remove their ticks. Thus, for the birds in this population to survive, they must work together. If they don’t, and some birds decide to “cheat” by having their ticks removed by “suckers,” but not reciprocating, the population will suffer. As fewer and fewer birds help their peers remove ticks, the population will become overrun with disease.
Given the direct benefit to the ...
