A Quantum Framework for 'Sour Grapes' in Cognitive Dissonance

This paper elaborates on a well-known and widespread bias -'cognitive dissonance'. The bias occurs when a person has conflicting cognitions framed by his/her values, beliefs etc. In such complex situations the individual choices and actions become emotionally tinted and thus inconsistent with the postulates of rational homo economicus. We evidence that classical probabilistic updating of information does not work correctly: hidden factors and motivations come into play to balance the conflicting cognitions and restore mental harmony. To support this inference we present a scheme of a 'gedanken experiment' in combination with known statistical data from a real experiment, the forbidden toy paradigm. Our findings show that the phenomenon of cognitive dissonance is a source of probabilistic non-classicality directly violating Bayes formula for conditional probability and so the law of total probability. Furthermore, we aim to show with the help of the quantum framework that the quantum probability formula and Hilbert space state representation of observables can well account for the 'incorrect behavior' among participants.