On Mental Transformations

The paper presents an alternative interpretation of the experimental data published by Kahneman and Tversky in their 1992 study "Advances in Prospect Theory”, which describes the Cumulative version of their Prospect Theory from 1979. It was assumed that, apart from the operations made during the initial stage of problem resolution, which Prospect Theory defines as Editing (here generalized as Mental Adaptation), other mental transformations such as Prospect Scaling (resulting from Focused Attention) and Logarithmic Perception of Financial Stimuli should be considered when analyzing the experimental data. This led to the design of an explicit, simple and symmetric solution without the use of the probability weighting function. The double S-type function obtained (the aspiration function) resembles the utility curve specified by the Markowitz hypothesis (1952) and substitutes the fourfold pattern of risk attitudes introduced by Cumulative Prospect Theory. The results presented constitute a basis for negating Prospect Theory as a theory which correctly describes how decisions are made under conditions of risk and may signal a return to a description of people’s behavior that only relies on the utility-like function.