Uncertainty and its perception: experimental study of the numeric expression of uncertainty in two decisional contexts

According to a consolidated tradition of research about the psychology of decisions (Newell, Lagnado & Shanks, 2007) and the psychometric psychology (Sartori, 2008), the present study aims at analysing the preferences of individuals between the main numeric expressions of uncertainty: the probabilistic form (expressed by percentages) and the fractional form (expressed by fractions). The purpose is to verify a different management of credit on the basis of a different expression of the representation of risk. The scientific outline refers to the most relevant studies in the field of decision making, which show the demonstrations and the experiments carried out by different authors starting from the investigations by Kahneman and Tversky. These results joined in their most accredited two theories: the Framing Effect and the Cumulative Prospect Theory, an evolution of the Prospect Theory. The following survey is designed to experimentally demonstrate the change in preferences on the basis of a different numeric representation of uncertainty. The study considers a generic sample of 100 individuals who were submitted two questionnaires especially designed. The obtained data were drawn up with statistic means in order to find out common norms in decision-making processes. The results showed the tendency of individuals to assign a different preference on the basis of the numeric representation, probabilistic or fractional. Referring to this feedback, one hypothesis is proposed as well as a new theory linked to the informative context of the options is presented.