Finanças comportamentais: um estudo descritivo dos vieses ancoragem e falácia da conjunção

Abstract

The literature oriented to behavioral process study involved in decision making and choosing situations shows that many times people make judgement mistakes. Among these judgement mistakes noticed in choosing situations, two bias situations are largely documented in behavioral and psychological literature: The Anchoring with insufficient adjustment and the Conjuction Fallacy. In general, the Anchoring is the behavior by which people make their estimatives motivated by base value or suggestions. The Conjunction Fallacy takes place when the conjunction of two events is assessed as more probable of happening than a single one. The purpose of this paper is to make a study to investigate which are the evidences of the Anchoring and The Conjunction Fallacy in the decision making process of investors, analysts, and investment professionals in capital market in Minas Gerais. Moreover, if these behaviors could be related among one another, fundamenting in theoretical assumptions presented by Amos Tversky and Daniel Kahneman, in 1974, in which three metaheuristic cognitives commonly used in judgement procedures, and in 1983, where the author exemplifies the occurrence of Conjunction Fallacy. For analysis, a virtual questionnarie for the investors, analysts, and investment professionals in capital market in Minas Gerais was used as a research tool. A sample method was used for judgement, which is characterized by non probabilistic samples, using the people from Analysts and Investment Professionals Association in Capital Market in the State of Minas Gerais (APIMEC-MG) and people registered in a broker in the city of Uberlândia, making use of all valid answers. For analysis, a statistical method with hypothesis test was used to compare with the mean obtained in the different questions of Anchoring, the unilateral hypothesis test of mean index to diagnose the Conjunction Fallacy bias, and the tetrachoric correlation test to measure the correlation of the two bias situations. The results found show that there were no evidences of Anchoring with insufficient adjustment bias nor Conjunction Fallacy bias among the interviewees. Moreover, it was also noticed that there is no correlation of behavior among investors, analysts, and investment professionals in capital market in Minas Gerais in showing evidence of both biases.