無知之幕：一個探討風險偏好與社會偏好的實驗

The Veil of Ignorance: An Experiment Investigating Risk and Social Preferences

羅盛華(Sheng-Hua Luo)

指導教授 ： 黃貞穎

國立臺灣大學/社會科學院/經濟學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.02902

摘要

本文以一個實驗探討人在無知之幕（Veil of Ignorance, VOI）之後的選擇是否可以由單純的風險偏好來解釋。受試者面對一系列彩券的選擇，每一次選擇都包含一個固定金額的選項以及一個具有風險的選項。一半的題目中，受試者的選擇只會影響自己的報酬；另一半的題目當中則是同時為自己以及另一位實驗參與者做出選擇，彩券的兩個獎項:大獎與小獎都會有人得到,若自己得到了大獎則會有另一位實驗參與者得到小獎,反之亦然。如果人在無知之幕背後的選擇完全可以由風險偏好所解釋，我們預期在兩種實驗環境中選擇將很近似。
另外一種可能是,受試者在無知之幕後面的偏好同時有風險偏好以及社會偏好,例如不均趨避(inequality aversion)，亦即受試者不喜歡見到自己和別人的報酬有所差距。
因此當實驗環境是幫自己與另一位實驗參與者共同做出選擇時，由於不希望見到報酬實現時自己的報酬和其他實驗參與者的報酬差太多，選擇時即會更傾向選擇無風險的固定金額選項。這個選項不僅表示自己的報酬無不確定性，同時也表示自己和另外一位實驗參與者的報酬必定相同。

關鍵字

實驗經濟學 ； 風險 ； 社會偏好

並列摘要

Using an experiment we hope to check whether decisions behind the veil of ignorance can be explained by pure risk preferences. Subjects faced a series of choices between two options, one risky lottery and one which gives a given amount of money with certainty. In half of the trials a subject’s decisions affect only his own payoff; in the other half he has to choose for himself and another participant in the experiment: both outcomes of the lottery will be won by a person; if the subjects wins the higher prize the other participant will win the lower prize and vice versa. If a subject’s decisions behind the veil of ignorance can be fully explained by his risk preference, we expect his behavior in the two experimental environments to be pretty similar.
Another possibility is, a subject’s preference behind the veil of ignorance include both risk preference and social preference, for example, inequality aversion, that is, the subject does dislikes to see there being a difference between his and another one’s payoffs.
Therefore, when the environment is to choose for himself and another participant, not hoping to see much difference between his own payoff and another’s when they are realized, when making decisions the subject tends to choose the riskless option. This option not only guarantees that there is no uncertainty in his payoff, but also that his and another participant’s payoffs will be the same.

並列關鍵字

risk preference ； social preference ； experimental economics

參考文獻

RAWLS, J. (1971). A theory of justice. Cambridge, MA, Belknap Press of Harvard University Press.

FEHR, E., & SCHMIDT, K. M. (1999). A Theory of Fairness, Competition, and Cooperation. The Quarterly Journal of Economics. 114, 817-868.

SCHILDBERG-HORISCH, H. (2010). Is the veil of ignorance only a concept about risk? An experiment. Journal of Public Economics. 94, 1062-1066