任何涉及交易的事件都可以是經濟學討論的對象。其中，交易雙方的誠信關係交易的均衡與效率，更是重要的議題。欺騙行為將導致交易成本的增加，因此抵銷交易所帶來的效率。若不考慮欺騙所帶來的不效率，則將高估交易的好處。若政府以相同邏輯制定相關之經濟政策，則可能造成錯誤決定，增加社會成本。
因此，本文將探討誠信對交易的影響，並根據其經濟意涵，提出改善交易效率的政策建議。然而，本文與傳統的欺騙理論不同之處在於，本文不僅加入心理特徵變數，更保有策略互動的架構，藉此讓理論更貼近實際行為。心理變數的功用在於引入欺騙行為所造成的心理成本。受騙方預期自己若被騙，將產生自尊心的扣損；施騙方預期自己若施騙，將產生罪惡感。再者，由於心理特徵屬於主觀的、且不易觀察的變數，故利用不完全訊息靜態賽局，將心理成本對應到彼此的類型，探討決策均衡。雙方皆不確知對手的類型，彷彿彼此皆面對一個採取混合策略的對手，再利用純策略貝氏均衡求解出彼此皆不後悔的決定。
本文最後指出，影響是否欺騙與相信的關鍵在於，共同訊息之種類。就訊息傳播的層面而言，媒體可以選擇揭露消費者或生產者的訊息。若現今的媒體影響力甚大，即交易雙方的態度受共同資訊影響甚大，則本文建議媒體應該多揭露「消費者捍衛自身權益」的新聞，而少揭露「生產者愛護自身商譽」的新聞。如此，將可以降低欺騙的機率與提高相信的機率。

When we talk about trade, everything could be considered by economics. The trust between trading counterparts determinant to the trading equilibrium and its efficiency is an important issue. On the other hand, deception will increase transaction cost which may cutback the benefit from trading; that is, the welfare will be overestimated once we ignore the inefficiency which deception causes. Therefore, if the government makes economic policies without taking deception problem into consideration, it might make wrong decisions, leading to higher social costs.
Due to the importance of trust, we want to explore theoretically the decision of deception, and further give some policy recommendations on improving trading efficiency.  Compared to the traditional deception theory, our model not only incorporates factors of mentality, which aim to describe the difference of personal characters, but also preserves the framework of strategic interaction. By doing so, our model can be more practical. Moreover, adding the mental variables can characterize the mental cost arisen from deception. For instance, someone will expect to experience the reduction of esteem if he or she is deceived, and will expect to have the feelings of guilt if he or she deceives. Further, since the mental characters are subjective and hard to be observed, our model indicates that people’s types can be represented by mental characters  which are their own private information . More specifically, players in a deception game don’t know each other’s types exactly. In this situation, people just like facing a person who chooses mixed strategies. By this way, we can get a pure strategy Bayesian equilibrium which warrants that no one will regret in the equilibrium.
  Based on the inference of the deception model, we find that the conjecture of the counterpart’s type is the key factor to determine whether deceive or not. At the view of information spreading, there are many ways to report the common knowledge, and especially media can report it relevant to consumers or producers. Recognizing the influence of media, we suggest that media should report more about “consumers’ tendency to fight for their right”, and less about “producers’ desire to value their reputation” so as to decrease the probability of deception and increase the probability of belief.

第一章  緒論	1
1.1  研究背景	1
1.2  研究目的	1
1.3  研究方法	3
1.4  研究架構	4
1.5  小結	5
第二章  文獻回顧	7
2.1  欺騙影響信任感	7
2.2  傳統模型	8
2.3  二元模型-包含心理因素與外在因素	9
第三章  研究方法與基本模型建立	14
3.1 基本假設與模型設計	14
3.2  一期模型	17
第四章  多期模型	29
4.1  本性與經驗	30
4.2  教育的作用	31
4.3  罪惡感的變動	32
4.4  欺騙模型心理變數的跨期變化	32
第五章  結論	37
參考文獻	39
附錄	41
數學附錄一	41
數學附錄二	47

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