P OPULAE thinking assumes conspicuous differences between the sexes in most traits. The nature and the extent of sex differences in abstract intelligence have received the attention of numerous psychologists. Tennan, Hollingworth, Whipple, and others have presented and discussed sex differences in this regard. (1) Summaries and discussions of miscellaneous studies of sex differences have been published recently by Allen, by Boynton, and by Groodenough.(2)Thorndike pointed out many years ago that the most striking fact about the sexes in most traits is the similarity as revealed in the amount of overlapping of distribution surfaces. (3) Miss Goodenough in a recent summary of representative studies in sex differences asserts: "The most outstanding impression which one gains from a comparison of these studies is the inconsistency of the various findings." (2 c, p. 441) The inconsistency of the earlier findings was perhaps due in part to crudity of techniques. The more recent investigations which employ more refined technique reveal consistent sex differences in certain traits. Goodenough summarizes the findings to date:"A slight superiority of females over males in general linguistic ability has been reported by practically all investigators in this field." (2 c, p. 444) "Studies made in the upper elementary grades and in high schools and colleges show a consistent difference in favor of the boys on practically all tests involving the use of number." (2 e, p. 449) "Data from a large number of sources show a consistent superiority of females over males in memory tests." (2 c, p. 450) "The weight of evidence . . . seems to point to the conclusion that boys have acquired a truly wider range of general information than have girls by the time they arrive at the beginning of the grammer school period, and there is some reason to believe that some degree of sex differentiation in this respect may be observed even during the pre-school period." (2 c, p. 453)"That boys and men on the average . . . greatly exceed women and girls in the ability to manipulate mechanical contrivances is not only a matter of common observation but has been brought out very clearly in an extensive investigation on me-
