ハイパーゲームによる搾取のモデル化とモデルケース分析

抄録

This paper analyzes exploitation arising from persistent misperceptions using hypergame theory. We define exploitation as a stable outcome in which an exploited player's subjective equilibrium is preserved while the realized outcome deviates from the equilibrium of the base game, generating a payoff gain for the exploiting player and a payoff loss for the exploited player. We formalize this phenomenon as Hyper Exploitation and examine its properties in both normal-form and extensive-form games. In particular, we prove that in a two-player complete-information extensive-form game with ordinal utilities, where the exploited player misperceives only the opponent's payoff, Hyper Exploitation cannot occur when the exploited player moves last. We then illustrate the mechanism with a stylized buyer-supplier price negotiation model. A supplier's misperception about the buyer's incentive to terminate the relationship makes a price cut subjectively rational and self-confirming, enabling a stable payoff transfer even without deliberate manipulation. The proposed framework clarifies when misperceptions can be sustained and how they can structurally lock in unequal outcomes.