Utilities in the 2-4-6 task.

The Wason 2-4-6 task was embedded in a practical reasoning scenario where number sequences had well-defined utilities in the process of achieving a goal. Reasoners' hypothesis-testing behavior was clearly goal-driven and was significantly influenced by whether the utilities favored positive or negative sequences. In the version of the scenario where generating positive sequences had greater benefits than generating negative ones, participants performed poorly at the task as measured by their ability to guess the correct rule and by the nature and number of triples tested before making an announcement. In contrast, the scenario that assigned a greater utility to the production of negative sequences fostered significantly more diligent and creative hypothesis-testing behavior, and participants were significantly more likely to discover the rule. These results suggest that the poor performance observed in Wason's traditional 2-4-6 task reflects a hypothesis-testing process that by default assigns greater utility to the production of sequences that conform to the initial triple, and hence receive positive feedback. However, reasoners are not averse to producing negative sequences, and understand their implication, if their utility is made relevant in the process of achieving goals.