From an article by Fareed Zakaria in the fall issue of Political Science Quarterly:
Soviet adventurism in the 1970s ... was bound to provoke an American response. And the speed and forcefulness of Reagan's response may have helped make the Soviet Union realize its blunder and begin correcting it.
In 1980 Robert Axelrod ran two tournaments for computer programs to determine what pattern of behavior one should use to elicit cooperation from an adversary. He was surprised to find that the strategy that won both tournaments was the shortest and simplest -- a program called Tit for Tat -- which consistently beat out highly sophisticated and nuanced alternative strategies. Analyzing its success, he suggested some rules to induce cooperation from a rival. First, be nice; don't be the first to stop cooperating. If you "defect," that is, stop cooperating, your adversary is likely to retaliate ... . Second, always reciprocate both defection and cooperation... . Third, don't be too clever. Highly complex strategies are incomprehensible, and if you appear unresponsive your adversary has no incentive to cooperate with you. Tit for Tat's great success is its clarity ... .
The Reagan strategy of containment followed strikingly similar lines. In response to what it saw as American cooperation during detente, Soviet expansionism in Southeast Asia, Africa and Afghanistan was viewed as rank defection. The Reagan strategy was to retaliate against this defection with the utmost clarity. When by 1986 the Soviet Union began cooperating, the administration held few grudges and quickly reciprocated that cooperation. The straightforwardness of this strategy -- which some saw as crudeness -- may go a long way in explaining the now blossoming partnership between the Soviet Union and the United States.