The Experimental Study On The Source Of Difficulties In MHD And The Facilitation Effects

An extremely hard conditional probability problem, known as the Monty Hall dilemma(MHD). This problem stirred much controversy when it first appeared in Marilyn Vos Savant's column in Panade magazine (September 9,1990). About 90% of the general public can't solve this problem, including university students and teachers. MHD problem (or three-door problem) is a famous example of a "cognitive illusion". From then on more and more psychologists were interested in the problem and committed themselves on it. They adopted various experimental methods in order to increase the proportion of correct reasoning and explain what makes it difficult. They found many interesting results. There are several theories about the causes of Monty Hall Dilemma's difficulty. They are natural frequencies theory, mental models theory, the collider principle in causal reasoning and the less-is-more effect theory. This article designed two experiments to study about the source of difficulties in MHD and the facilitation effects. In experiment 1, we guided participants to represent the three-door problem by two-step and two-group way. We expected in this way could make participants be able to understand the internal relation of the problem and solve it correctly. Moreover, we expected there is a facilitation effect on the solution of the transfer problem. In experiment 2, we changed the adversary game of Tubau(2003) that took the form of a card game between two participants(decision maker and informant). We added the third person in game to open a non-ace for showing it to the decision maker. By doing so, we ensure that the information amount given to both adversaries is equivalent. We expected this manipulation result in less correct responses to game. This result shows that the information amount given to both adversaries is one of factors that influence the experimental results under competition circumstances.This experimental study chose the undergraduates from Chongqing University as participants, Then, the article came to the conclusion as follows:(1) The participants' performance was improved through representing three-door problem's structure as a whole by two-step and two-group way.(2) There was not a significant facilitation effect on the solution of the complex realistic problem.(3) In the adversary game of Tubau(2003 ), the information amount given to both adversaries is one of factors that influence the experimental results.(4) The MHD problem was presented in the form of an adversary game that make more participants represent and solve problem correctly.