Generosity: A winner's advice.


One day while I was still at Oxford, Bob May gave me some advice: “You never lose for being too generous”. I was impressed because Bob is a winner. To him winning a game is everything. He has thought more deeply about winning and losing than anyone else I know. As his wife once said, “When he plays with the dog, he plays to win.” At the time, Bob was not only my adviser but also one to the British government. A few years later he would become president of the Royal Society, Lord May of Oxford and the recipient of many prestigious awards. A mathematical analysis of human behaviour suggests that Bob was right. Generosity is an essential feature of winning strategies in games that explore human interactions. These strategies underpin many of the choices people make in everyday life, and shed light on how our unusually cooperative ways have evolved. Biologists recognize two fundamental forces of evolution: mu tation and selection. I want to add a third: co operation. Cooperation occurs when one individual pays a cost so that another receives a benefit. Here, cost and benefit are measured in terms of reproductive success. Reproduction can be genetic or cultural, the latter involving the spread of knowledge and ideas. Only if certain mechanisms are involved can natural selection favour individuals who reduce their own fitness to increase that of a competitor. One such mechanism is direct reciprocity: my strategy depends on what you have done to me. Another is indirect reciprocity: my strategy depends on what you have done to me and on what you have done to others. In both, mathematical analysis shows that winning strategies tend to be generous, hopeful and forgiving. Generous here means not seeking to get more than one’s opponent; hopeful means cooperating in the first move or in the absence of information; and forgiving means attempting to re-establish cooperation after an accidental defection. These three traits are related. If I am generous, it is easier for me to forgive, and also to be hopeful and take the risk of cooperating with newcomers. In the Wimbledon championship, you must defeat your opponent to move to the next round. But everyday life is not like a tennis tournament. Instead, most of our interactions occur in a population of players, and pay-off accumulates over encounters with many different people. Because overall success is proportional to that pay-off sum, the other person in any one encounter is more a partner than an opponent. If I am willing to let others have a slightly bigger share of the pie, then people will want to share pies with me. Generosity bakes successful deals. Experiments have confirmed the success of generosity. A typical set-up involves students and computer screens. The computer pairs

DOI: 10.1038/456579a

Cite this paper

@article{Nowak2008GenerosityAW, title={Generosity: A winner's advice.}, author={Martin A. Nowak}, journal={Nature}, year={2008}, volume={456 7222}, pages={579} }