On the relation between irrationality and probability estimates in a game of chance

Based on Rational Emotive Behavior Therapy (REBT) we tested the hitherto unexplored assumption that irrationality as conceptualized by REBT (demandingness, self evaluation, low frustration tolerance), is associated with erroneous statistical reasoning. We assessed trait irrationality of 216 respondents and individual estimates of future winning probabilities in the context of the Wortman (1975) perceived control design. Results indicate that an increased (i.e., unrealistically optimistic) as well as a decreased (i.e., unrealistically pessimistic) estimation of future winnings is associated with irrationality. Findings substantiate an association between erroneous probability estimates and therapeutically relevant cognitions which do not imply any mathematical or statistical contents.