Introversion/extroversion, time stress, and caffeine: effect on verbal performance

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Science  09 Apr 1976:
Vol. 192, Issue 4235, pp. 149-150
DOI: 10.1126/science.1257762


Time pressure and caffeine differentially affected the performance of introverts on verbal ability tests similar to the Graduate Record Examination. With time pressure and 200 milligrams of caffeine, the performance of introverts fell by 0.63 standard deviation, but extroverts by 0.44 standard deviation.