在總體經濟學中，跨期替代分析方法佔有相當重要的地位。其中跨期替代彈性(the
elasticity of intertemporal substitution, EIS)的大小，間接或者直接影響總體經濟中的許多層面，直覺上，例如跨期替代彈性越大，對個人而言，是對當期消費的機會成本提升，使延後消費的意願上升，同時增加個人儲蓄，在正常金融市場情況之下，個人儲蓄金額的增加，將使市場資金的供給量增多，使得企業或個人的投資機會成本降低，經由總體經濟中間接或直接的影響下，則總體經濟成長率應會上升。其中，當消費者效用函數為固定風險趨避係數(constant coefficient of relative risk aversion, CRRA)且具有跨期分割與可加性的特性，加上在傳統經濟學中，假設每個人皆為完全理性的前提下，經由跨期替代分析方法推導後，可以得到相對風險趨避係數(the coefficient of relative risk aversion, RRA)與跨期替代彈性(the elasticity of intertemporal substitution, EIS)恰好是倒數關係。

在過去相關研究中，Hansen and Singleton (1983)推估出跨期替代彈性值較大且顯著，但Hall (1988)強調，若考慮資料的時間加總問題(time aggregation problem)，
則前者估計出跨期替代彈性在統計上則不再是顯著；Hall亦於結論提出跨期替代彈性為小於或等於0.1，甚至比0小。在經濟意義上，代表股票市場中投資人的相對風險趨避程度(RRA)極大，直覺上，是不合理的現象，這也是著名的彈性迷思(elasticity puzzle)。於是Epstein and Zin (1991)嘗試建議並修正效用函數為不具時間分割性(non-time separable utility)的效用函數，並得到跨期替代彈性(EIS)與相對風險趨避係數(RRA)互為倒數關係，不復存在的結論。這也說明影響彈性迷思(elasticity puzzle)的原因有許多，其中之一，可能為設定不同形式效用函數所造成。

在傳統經濟模型中，假設完全理性的個人決策行為之下，利用跨期替代方法，可以得到跨期替代彈性(EIS)與相對風險趨避程度(RRA)互為倒數關係後，又得到隱含風險趨避程度為無窮大的推估結論。這也是本研究想要來探究的問題，即是彈性迷思(elasticity puzzle)究竟是假設所造成，或者是因為由個體資料加總成總體資料，所產生的謬誤。

因此，本研究與其他研究不同之處，在於利用建構時間可分離形式的效用函數(time-separable utility)模型基礎，以遺傳演算(Genetic Algorithms)方法，建構有限理性的人工股票市場進行模擬，其中，模擬方式為設定不同代理人(agent)有不同程度的預測能力，代表其理性程度的差異的表現。

本研究發現在有限理性異質性個人的人工股票市場下，相對風險趨避程度係數(RRA)與跨期替代彈性(EIS)不為倒數關係，且設定不同代理人不同的預測能力，亦會影響跨期替代彈性(EIS)的推估數值大小。

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