Prospect theory (PT) is the dominant descriptive theory of decision making under risk today. For the modeling of choices, PT relies on a psychologically founded separation of risk attitudes into attitudes towards outcomes, captured in a value function; and attitudes towards probabilities,...

We test the effect of stake size on ambiguity attitudes. Compared to a baseline condition, we find subjects to be more ambiguity seeking for small-probability gains and large-probability losses under high stakes. They are also more ambiguity averse for large-probability gains and...

We examine situations in which a decision maker decides for another person as well as herself under conditions of payoff equality, and compare such decisions under responsibility to individual decisions. Estimating a structural model we find that responsibility leaves utility curvature...