The efficient market hypothesis (EMH), based on rational expectations and market equilibrium, is the dominant perspective for modelling economic markets. However, the most notable critique of the EMH is the inability to model periods of out-of-equilibrium behaviour in the absence of any significant external news. When such dynamics emerge endogenously, the traditional economic frameworks provide no explanation for such behaviour and the deviation from equilibrium. This work offers an alternate perspective explaining the endogenous emergence of punctuated out-of-equilibrium dynamics based on bounded rational agents. In a concise market entrance game, we show how boundedly rational strategic reasoning can lead to endogenously emerging crises, exhibiting fat tails in "returns". We also show how other common stylised facts of economic markets, such as clustered volatility, can be explained due to agent diversity (or lack thereof) and the varying learning updates across the agents. This work explains various stylised facts and crisis emergence in economic markets, in the absence of any external news, based purely on agent interactions and bounded rational reasoning.
翻译:以合理期望和市场平衡为基础的高效市场假设(EMH)是模拟经济市场的主要观点,然而,对EMH最显著的批评是,在没有重大外部新闻的情况下,无法模拟不平衡行为期的模型。当这种动态出现时,传统经济框架无法解释这种行为和偏离平衡的情况。这项工作提供了另一种观点,解释基于受约束的合理因素的自发平衡动态的内在出现。在简洁的市场进入游戏中,我们展示了狭隘的理性战略推理会如何导致内生危机,在“回报”中表现出脂肪尾巴。我们还展示了经济市场的其他常见的板块化事实,如集束波动,如何被解释为代理人的多样性(或缺乏这种多样性)以及代理人之间不同的学习最新情况。这项工作解释了在没有任何外部新闻的情况下,纯粹基于代理人互动和封闭的理性推理,各种僵化的事实和在经济市场上的危机出现。