Jones and Berglas gave people positive feedback following a problem-solving test, regardless of actual performance. Half the participants had been given fairly easy problems, while the others were given difficult problems. Participants were then given the choice between a "performance-enhancing drug" and a drug that would inhibit it. Those participants who received the difficult problems were more likely to choose the impairing drug, and participants who faced easy problems were more likely to choose the enhancing drug. It is argued that the participants presented with hard problems, believing that their success had been due to chance, chose the impairing drug because they were looking for an external attribution (what might be called an "excuse") for expected poor performance in the future, as opposed to an internal attribution.