The 'expected utility hypothesis' is one of the foundations of classical
approaches to economics and decision theory and Savage's 'Sure-Thing Principle'
is a fundamental element of it. It has been put forward that real-life
situations exist, illustrated by the 'Allais' and 'Ellsberg paradoxes', in
which the Sure-Thing Principle is violated, and where also the expected utility
hypothesis does not hold. We have recently presented strong arguments for the
presence of a double layer structure, a 'classical logical' and a 'quantum
conceptual', in human thought and that the quantum conceptual mode is
responsible of the above violation. We consider in this paper the Ellsberg
paradox, perform an experiment with real test subjects on the situation
considered by Ellsberg, and use the collected data to elaborate a model for the
conceptual landscape surrounding the decision situation of the paradox. We show
that it is the conceptual landscape which gives rise to a violation of the
Sure-Thing Principle and leads to the paradoxical situation discovered by
Ellsberg.Comment: 11 page
