EFFECTS OF ESTROGEN CHANGES DURING THE MENSTRUAL-CYCLE ON SPATIAL PERFORMANCE

Four sequential, interrelated studies of the relationship of menstrual cycle phase to three-dimensional mental rotations performance were conducted, using both between- and within-subjects designs. All studies showed significant increases in mean mental rotations scores during the menstrual period phase, when estrogen levels were at their lowest. Effects occurred only for mental rotations; relationships with hormonal status did not occur for control tests, which were not of a spatial nature, and a different spatial test (Space Relations). Findings are discussed as they relate to ontogenetic development and evolutionary origins of sex-specific differences in spatial behaviors.