Tit for tat

Tit for tat (or tit-for-tat) is an English saying dating to 1556, from "tip for tap", meaning "blow for blow," i.e., retaliation in kind—or more broadly, an equivalent to an action given in return. It has related meanings and use as a concept in biology, social psychology, business, as well as in the mathematical area of game theory. The concept in its various forms has found use in the real world in attempting to explain a form of reciprocated altruism in animal communities, and as a strategy for managing activities in technology areas.

Tit for tat is an English expression that is used to refer to "retaliation in kind", or more broadly, for any "equivalent [to an action] given in return." It is thought to have evolved from the earlier expression, "tip for tap," where the connotation of "tip" is "blow", as in to strike physically (e.g., as in "blow for blow"); its reported first appearance was in 1556.

"Tit for tat" has been used to describe the concept behind how groups of animals have come to live in largely or entirely cooperative societies, rather than the individualistic "red in tooth and claw" way that might be expected from individuals engaged in a Hobbesian state of nature. This, and particularly its application to human society and politics, is the subject of Robert Axelrod's book The Evolution of Cooperation.

The tit-for-tat strategy has been of beneficial use to social psychologists and sociologists in studying effective techniques to reduce conflict. Research has indicated that when individuals who have been in competition for a period of time no longer trust one another, the most effective competition reverser is the use of the tit-for-tat strategy. Individuals commonly engage in behavioral assimilation, a process in which they tend to match their own behaviors to those displayed by cooperating or competing group members. If the tit-for-tat strategy begins with cooperation, then cooperation therefore ensues. On the other hand, if the other party competes, then the tit-for-tat strategy will lead the other party to compete as well. Each action by the other member is countered with a matching response, competition with competition and cooperation with cooperation.

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