Sex difference research has been plagued with a myriad of problems,. Specifically, intelligence testing, if dependent on measurement of spatial or verbal proficiency, may not be an accurate indicator of native ability. Similarly, infrequent replication of studies, studies that only include subjects of one sex yet imply sex differences, and poor test validity are issues that concern the researcher. Cultural expectations may largely account for sex role differences and ethnic stereotyping, although causes are elusive. According to the review of research conducted by Maccoby and Jacklin (1974), the following myths may be defined: Girls are more social, "suggestable," auditory, and affected by heredity than boys; girls are better at rote learning and have lower self esteem than boys; boys are more analytic, achievement oriented, and affected by environment than girls. Research "realities" include evidence that while girls have greater verbal ability than boys, boys excel in visual-spatial ability, mathematical ability, and are more aggressive than girls. The physiological basis for these differences (such as brain lateralization, hormones, etc.) has not been substantiated. Rather, the notion of cultural reinforcement seems much more realistic. (KS)