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Cognitive Hierarchy Theory (CHT) is a behavioral model originating in behavioral economics and game theory that attempts to describe human thought processes in strategic games. CHT aims to improve upon the accuracy of predictions made by standard analytic methods (including backwards induction and iterated elimination of dominated strategies), which can deviate considerably from actual experimental outcomes. ==Framework== Like other theories, Cognitive Hierarchy Theory assumes that players in strategic games base their decisions on their predictions about the likely actions of other players. According to CHT, players in strategic games can be categorized by the "depth" of their strategic thought.〔Nagel, Rosemarie. "Unraveling in Guessing Games: An Experimental Study". The American Economic Review, Vol. 85, Issue 5. December 1995〕 It is thus heavily focused on bounded rationality. A completely non-strategic player will choose actions without regard to the actions of other players. Such a player is said to have zero-order beliefs and may also be called a level zero player. A slightly more sophisticated (level one) player believes that the other players will act non-strategically; his or her action will be the best response consistent with those first-order beliefs. An even more sophisticated (level two) player acts on the belief that the other players are level one. This pattern continues for higher-level players, but each player has only a finite depth of reasoning, meaning that individual players have a limit to the depth to which they can reason strategically. In its basic form, CHT implies that each player believes that he or she is the most sophisticated person in the game. Players at some level k will neglect the fact that other players could also be level-k, or even higher. This has been attributed to many factors, such as "maintenance costs" or simply overconfidence.〔Stahl, Dale and Wilson, Paul. "On Players' Models of Other Players: Theory and Experimental Evidence". Games and Economic Behavior. 10, 1995〕 Some theorists, 〔Camerer, Colin F., Teck-Hua Ho and Juin-Kuan Chong. "A Cognitive Hierarchy Model of Games". The Quarterly Journal of Economics. Aug. 2004〕〔 have noted that players do not necessarily fall under the archetypes above. Instead, a player can act under the assumption that some percentage of the population fits each archetype, and act accordingly to find the best response. For example, in the Keynesian Beauty Contest described below, a player might believe that half the players are level-zero, and half are level-one. This player would select a number about halfway between the guesses of the archetypal level-one and level-two players. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cognitive Hierarchy Theory」の詳細全文を読む スポンサード リンク
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