Our Cro-Magnon anthropologist, then, would conclude that the social environment of the EEA would be defined by an acute tendency to care, by highly coordinated, face-to-face social exchanges, by the need to reconcile and the flattening of social hierarchies, by perpetually negotiated conflicts of interests, and by the emergence of the tendency toward sexual monogamy. It is these properties of our early social existence that gave rise to the moral emotions, of interest to Darwin but long ignored by the science of emotion that he inspired. Compassion, embarrassment, awe, love, and gratitude emerged in the recurring social interactions of early hominid social life: the attending to vulnerable offspring, the playful exchanges between kith and kin, the status moves and negotiations, the courtships and flirtations between current and potential sexual partners. These emotions were wired into the body and our social life through processes of natural and sexual selection. They evolved into the language of human social life, the species-characteristic patterns of parent-offspring relations, relations between mates and allies, dominant and subordinate members of hierarchies, and in mating relationships. These emotions became our ethical guides to help us fold into stable, cooperative communities. They operated according to three general principles, revealed in a tournament that pitted the brightest mathematicians and computer hacks against one another in an attempt to discover what strategies prevail in the survival of the fittest.
THE WISDOM OF TIT-FOR-TAT AND THE GREAT SHIFT
In
Axelrod himself was taken aback by striking acts of cooperation that confound assumptions about self-preservation and self-interest. In the trenches of World War I, for example, British and French soldiers were separated from their enemies, the Germans, by a few hundred yards of burned-out, treeless, muddy no-man’s-land. Brutal assaults by one side were typically met with equally fierce, lethal attacks by the other. And, yet, in these nightmarish patches of annihilation, cooperation emerged. The two sides flew certain special flags, signaling nonconfrontation. They made verbal agreements not to shoot at each other. They evolved patterns of firing their weapons in purely symbolic, harmless ways, to signal nonlethal intent. All of these cooperative strategies allowed the soldiers to eat meals peacefully and to enjoy long periods of nonengagement. On special occasions, the warring sides even fraternized with one another. In fact, cooperation became so pervasive that commanding generals had to intervene, demanding a return to deadly combat.
From historical anecdote Axelrod turned to the prisoner’s dilemma game (see table below) to answer his question about the evolution of cooperation. He conducted a tournament in which players—cold war strategists, psychologists, prize-winning mathematicians, computer specialists, and other aficionados of the game—were invited to submit computer programs that specified what choice to make on a certain round of the prisoner’s dilemma game, given what had happened in previous rounds. In Axelrod’s first tournament, fourteen different strategies were submitted. Each was subsequently pitted against the others for 200 rounds. Here the game really mirrors human social life. Individuals with different strategic approaches went toe-to-toe with one another, much as bullies and altruists do on the grammar-school playground, Machiavellians and kindhearted colleagues do at work, hawks and doves do in foreign policy debate, and presumably our hominid predecessors—genetically prone, through random mutation, to cooperate or compete—did. Who prevailed?
THE PRISONER’S DILEMMA GAME (PDG)
PARTNER’S ACTION
COOPERATE
COMPETE
YOUR ACTION
COOPERATE
5,5
0,8
COMPETE
8,0
2,2