Abstract
In this paper, I clarify a process that produces power structure, under which some people choose a cooperative act by altruistic motive and other people choose an uncooperative act by selfish motive. By using evolutionary game models, I prove the following propositions: 1) When it is assumed that players can choose their payoff functions under the condition that the probability of continuation of the game is low, altruistic players who choose a cooperative act appear at a certain proportion, and the state is stable; 2) In that case, selfish players exploit altruistic players. Therefore, it is concluded that interactions with no constraints are able to produce power structure, and that selfish players exploit altruistic players in such power structure.
