This study has a bearing on the question of sex differences in temperament, and brings out different results from similar studies made previously. The subjects were students at the University of Minnesota, and the instrument of measurement was Freyd's list of 54 introvert traits. The data gathered show that under the conditions of this study there is little or no difference between men and women in introversion and extroversion. Certain sex differences in temperament appeared, aside from the matter of introversion and extroversion. Sex differences in temperament and introvert-extrovert differences did not run parallel to each other, but acted as independent variables. (PsycINFO Database Record (c) 2006 APA, all rights reserved)