AbstractTwo studies were conducted to determine the kinds of questions people formulate for testing a hypothesis about another's personality. One group of subjects tested the hypothesis that the interviewee was an extrovert; another group tested the hypothesis that the interviewee was an introvert. Still another group was not provided with a hypothesis; instead, this group was asked to discriminate between an extroverted and an introverted interviewee. All subjects were free to formulate any kind of questions they wished. Analysis of the content of the questions performed by independent judges revealed that the great majority of the questions formulated by all of the groups either presented a choice between extroverted and introverted features or were open‐ended. The percentage of questions about features that were consistent with the hypothesis was not significantly greater than the percentage of questions about features that were inconsistent with the hypothesis. Furthermore, in all of the groups there were virtually no biased questions–questions that already assume that the hypothesis is true. Finally, the questions asked by subjects who entertained either the extrovert hypothesis or the introvert hypothesis were as diagnostic (as rated by independent judges) as were the questions asked by subjects whose task was to discriminate between extroverts and introverts. The results were shown to be consistent with the diagnosing strategy but not with the confirmatory strategy of information‐gath