本文主要在探討不完整訊息下加入群眾影響的個人決策行為，以二階段的訊息賽局模型為架構分別探討「單一訊息」與「雙重訊息」影響下的決策差異。其中雙重訊息係為具成本的訊息（signaling）與不具成本的空談訊息（cheap talk）二種，而空談訊息的來源為群眾的觀感或經驗談，此類訊息的數量多寡與正、負面向皆會對訊息接收者的決策報酬造成影響進而改變訊息接收者的決策行為。此外，在二個模型中皆引入了外生給定的行為成本（市場價格），使得均衡策略是有條件式的存在，即使在同樣的行為成本（市場價格）下，單一訊息模型與雙重訊息模型中的均衡策略也不盡相同。結果將可反應出：在不完整訊息下，訊息接收者的決策行為明顯受到群眾訊息數量與正、負面向的影響，當訊息接收者接收到群眾正面觀感的訊息時，即使面對較高的行為成本（市場價格）亦將採取採納的行動，而訊息發送者則可利用此結果擴大群眾訊息的影響，獲得更大的收益。

The thesis discussed decision maker’s behavior under herding of incomplete information. We consider two-stage signaling games to analyze the differences of decisions between the one signaling game and two signaling game. Two signals include both cost signaling and costless signaling, the former is signaling with cost and the latter is the cheap talk. The cheap talk comes from public who just talk straight about their perceptions, impressions and experiences. The quantities and the perception dimensions of that kind of information will affect receivers’ payoff and also the decision behaviors. An exogenous price is also considered that affects equilibriums existence. For the same price, decision behavior may act differently in the case one signaling game and that two signaling game. The result shows that : in the incomplete information, the quantities and the perception dimensions of public information will obviously affect decision behavior and receivers will accept senders even at higher price. This leads senders to expand herding effect to acquire more profit.

目       次

第一章	緒論 …………………………………… 1
第二章	單一訊息賽局 ………………………… 4
第一節	模型設定 ……………………………… 4
第二節	單一訊息賽局均衡………………………9
第三節	小結…………………………………… 15
第三章	雙重訊息賽局 ………………………  17
第一節	模型設定 ………………………………17
第二節	雙重訊息賽局均衡…………………… 23
第三節	小結…………………………………… 37
第四章	結論 …………………………………  41
參考文獻 ………………………………………… 43
附錄A：單一訊息賽局均衡求解………………   44
附錄B：雙重訊息賽局均衡求解………………   54

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