Guessing the beliefs

A decision maker facing Knightian uncertainty is about to tell if he prefers an act X or Y. Two agents try to guess what he is going to do. All of them have preferences that achieve a separation of utility from beliefs. The only thing that the two agents do not know is the beliefs, so they evaluate them. We give a definition of “guessing better” and deal with its implications. We study particular cases as subjective expected utility and Choquet expected utility.