We provide the first tests to distinguish whether individual investors equally balance their overall portfolios (naïve portfolio diversification--NPD) or engage in naïve buying diversification (NBD)--equally balancing values in same-day purchases of multiple assets. We find NBD in purchases of...

A decision maker constructs a convex set of nonnegative martingales to use as likelihood ratios that represent parametric alternatives to a baseline model and also non-parametric models statistically close to both the baseline model and the parametric alternatives. Max-min expected utility over...

One of the most complex systems is the human brain whose formalized functioning is characterized by decision theory. We present a quot;Quantum Decision Theoryquot; of decision making, based on the mathematical theory of separable Hilbert spaces. This mathematical structure captures the effect of...

Quantum decision theory (QDT) is a recently developed theory of decision making based on the mathematics of Hilbert spaces, a framework known in physics for its application to quantum mechanics. This framework formalizes the concept of uncertainty and other effects that are particularly manifest...

We present the first calibration of quantum decision theory (QDT) to an empirical data set. The data comprise 91 choices between two lotteries (two "prospects") presented in 91 random pairs made by 142 subjects offered at two separated times. First, we quantitatively account for the fraction of...

We prove the existence of Pareto optimal allocations within sets of acceptable allocations when decision makers have probabilistic sophisticated variational preferences defined on random endowments in L1. Pareto optimal allocations, variational preferences, probabilistic sophistication,...

Decision making of agents who are members of a society is analyzed from the point of view of quantum decision theory. This generalizes the approach, developed earlier by the authors for separate individuals, to decision making under the influence of social interactions. The generalized approach...

This paper discusses health economics as a behavioral science and as input into health policy and health services research. I illustrate the dual role with data on publications and citations of two leading health economics journals and three leading American health economists. Five important,...