Nicholas Wade of the New York Times is a science writer I have always admired. He wrote this article on the sense of fairness ( NY Times Sept.18 2003) which we think is unique to humans. Mr. Wade describes an experiment done with capuchin monkeys in which the monkeys are taught to trade pebbles for food. The monkeys are placed so that they can see each other. Two food items are traded, a less favored cucumber and the much desired grape. If a capuchin gets a cucumber but sees his companion being handed a grape the monkey throws a fit. The behavior suggest that monkeys have evolved a sense of fair play, something which may be an essential attribute for living in social groups. It is a most interesting piece of research and also well reported.
To summarize Mr. Wade writes
"Selfishness might seem the best way for an individual to get the most genes into the next generation, evolution's only coin of success. But biologists have come to understand how cooperative behavior, under certain definable conditions, can have a greater genetic payoff and therefore how genes that foster such behavior could be favored by evolution"
This point needs clarification since biology has seen a bitter debate about selfish genes and genetic determinism. The way Mr. Wade put it seems to imply that selfish behavior exhibited by an individual is the more successful strategy in animals and co-operation can evolve only under certain conditions. But I doubt if there is any data to suggest that any one of these behaviors is more common than the other in social animals. An individual may show kindness and generosity towards kin and be a selfish brute to strangers. In fact I would guess that co-operation at least within kin is more common. The term “selfishness” in his article really reflects the metaphorical motives of genes and not the real motives of individuals. These are not necessarily the same motives. Both selfish and co-operative behaviors are contingent strategies which have evolved in certain circumstances such as living in highly social groups. Which one is employed depends upon an unconscious cost-benefit analysis of the greatest chance of reproductive success. The ultimate causation of both these behaviors is the gene's metaphorical selfish motive in getting the most copies of itself into the next generation. Thus ‘selfish genes’ (ultimate level) don't automatically produce selfish behavior (proximate level).
This clarification of the meaning of “Selfishness” is crucial since one of the biggest misapprehensions about evolution is that if genes have selfish motives then individuals will always behave selfishly with the obvious distasteful implications for human behavior. This need not be so since "selfishness" is the genes metaphorical motive which can lead to a wide range of behaviors ranging from selfishness to altruism in individuals.