Comportamento de Escolha: Uma estimativa de probabilidades subjetivas de descrições nominais com recompensas hipotéticas

Abstract

In most of the time, people tend to describe frequency or probability of events with words instead of numbers. The description of an event with words may lead to misunderstanding its actual probability. These descriptions have been used in several psychological instruments, but there are no systematic investigations on how different individuals may be affected by them. The aim of present work was to estimate equivalent numerical probabilities to the chances to receive a probable hypothetical amount of money presented with nominal descriptions for 33 undergraduate students. The task consisted in choices between a large amount of money and small amounts, which was adjusted up and down. The experiment was divided in two phases: in one the chances to receive the large amount was presented with percentage (10% to 90%), and in the other, the chances were presented with words. A power function showed to be a better description of individual indifference values than a hyperbolic one. The free parameters calculated from linear regression obtained with numerical probabilities were used to estimate the equivalent probabilities to nominal descriptions. The results showed that both estimated probabilities and indifference values were variable among participants. Some differences came from conditions as well as adjusting exposition order. These results reinforce the necessity to use quantitative measures in psychological evaluation instruments, so it can be more sensitive to these differences.