This paper examines data from the Norwegian television game show Joker, where contestants make well-specified choices under risk. The game involves very large stakes, randomly drawn contestants, and ample opportunities for learning. Central models of risk choice, including expected utility theory, give a simple prediction of choice under weak conditions, as one decision is always first-order stochastically dominating. We document frequent, systematic and costly violations of dominance. Many contestants appear to have a systematic expectation bias that can be related to Tversky and Kahneman's (Cogn. Psychol. 5(2):207-232, 1973) “availability heuristic”. In addition, contestants seem to make systematic calculation errors that are well captured by the so-called Fechner model.
