基於凱因斯選美競賽概念我們知道，如果要掌握金融市場的整個運作過程，除了要了解市場參與者所持有的信念外，更要進一步去了解市場參與者對其他市場參與者的信念的可能看法，也就是所謂的高階信念。因此，本篇研究的主要目的是嘗試描述高階預期概念在資產定價模型中所扮演的角色，同時也可以檢驗凱因斯的選美競賽理論是否可以幫助我們了解資產價格的形成過程。第二個目的是利用資產定價模型進一步去檢視市場交易者是否對公開訊息有過度反應的現象。 透過建立噪音的理性預期模型來推導外匯價格的預期形成過程發現，外匯價格所傳遞的訊息為偏誤的訊息，亦即在供給衝擊下的平均外匯價格並不會完全反映外匯真實價值，其反映的是外匯資產真實價值及公開訊息的線性組合。此外，經過進一步研究後發現，外匯價格的預期受公開訊息的影響程度遠大於真實訊息，亦即市場上的外匯價格預期對公開訊息有過度反應的現象。 另外，模型的研究結果指出，造成市場參與者對於公開訊息產生過度反應的原因有：投機者的人數比例、投機者的風險愛好程度以及私有訊息的精確度等三項。 / Based on Keynes’s beauty contest theory, if you want to know the operation of financial market, you should understand market participants' beliefs and market participants' beliefs about other market participants’ beliefs, which is called the higher order beliefs. The goal of the paper is to illuminate the role of higher order expectations in the asset pricing model, and thereby to explore the extent to which Keynes’s beauty contest theory is useful in thinking about asset prices. The second goal of this paper is to use the asset pricing model to examine whether market participants overreact to public information. By setting up the noisy rational expectations model, we know that exchange rate is biased signal of the underlying fundamental value. Mean exchange rate taken over realization of the supply shocks are given by convex combination of the true value and public information. Moreover, the distribution of exchange rates is biased towards public information relative to the true value. That is, there is an overreaction to public information. Finally, the model indicates that there are three factors to explain why market participants overreact to public information. These factors are the proportion of speculators, the risk aversion of speculators and the precision of private information.