Abstract The hypothesis that degree, direction, and magnitude of sex difference in psychological differentiation is partially a function of cultural influence was tested. Ss were 120 ten-year-old boys and girls from Jewish populations differing in their fidelity to the cultural patterns of Eastern-European Jews. The less traditional group attained more differentiated scores on four measures—even when verbal ability was controlled. On two additional measures the differences did not reach statistical significance. Among both groups girls drew more sophisticated pictures on the Figure Drawing Test than did boys. Additionally, more traditional girls obtained more differentiated scores on Object Assembly—a direction of sex difference opposite to that usually obtained in Western cultures. On Block Design and Embedded Figures the higher scores attained by girls did not reach statistical significance. Sex differences on Rod and Frame were in the usual direction; i.e., boys obtained more differentiated scores than...