Ellsberg thought experiments and empirical confirmation of Ellsberg preferences pose serious challenges to subjective expected utility theory (SEUT). We have recently elaborated a quantum-theoretic framework for human decisions under uncertainty which satisfactorily copes with the Ellsberg paradox and other puzzles of SEUT. We apply here the quantum-theoretic framework to the Ellsberg two-urn example, showing that the paradox can be explained by assuming a state change of the conceptual entity that is the object of the decision (decision-making, or DM, entity) and representing subjective probabilities by quantum probabilities. We also model the empirical data we collected in a DM test on human participants within the theoretic framework above. The obtained results are relevant, as they provide a line to model real life, e.g., financial and medical, decisions that show the same empirical patterns as the two-urn experiment.interpretation of a wide range of cognitive phenomena in terms of standard logic and probability theory. On the other side, Kahneman, Tversky and other authors suggested that these empirical deviations from classicality are "true errors" of human reasoning, whence the use of terms like "effect", "fallacy", "paradox", "contradiction", etc., to refer to such phenomena [4,5]. 1 An innovative aspect of the Kahneman-Tversky programme of judgement heuristics and individual biases was the use of non-Kolmogorovian structures to represent probabilities. In that regard, the research on the foundations of quantum theory has unveiled both the conceptual and mathematical differences between classical and quantum structures, e.g., context-dependent situations crucially need a non-Kolmogorovian quantum-like model of probability (see, e.g., [7,8,9]). This was the starting point of a successful research that applies the mathematical formalism of quantum theory, detached from any physical interpretation, to model situations in cognition and economics that cannot be modelled by classical structures (see, e.g., [6,7,8,9,10]).Why are classical structures problematical in SEUT? In 1961, Daniel Ellsberg proposed a series of DM experiments whose results do not agree with the predictions of SEUT, as far as concrete decisions are mainly influenced by psychological factors, like ambiguity aversion, rather than by the need of maximizing EU [11]. The consequence is that one cannot represent Ellsberg preferences by maximization of EU with respect to a unique Kolmogorovian probability measure, which generates the famous Ellsberg paradox. Ellsberg preferences have been empirically confirmed several times against the predictions of SEUT and its main extensions, in simple DM tests, but also in more complex real life DM situations (see, e.g., [12]).How does the research on quantum structures relate to the pitfalls of SEUT? The answer comes from a 20-year research on the foundations of quantum physics, the origin of quantum structures and the conceptual and mathematical differences between classical and quantum theories. Indeed, we...