The anisotropic properties of space have received intermittent study for some time. Takala (i i) in his summary of the pertinent literature and also in his own experimental work pointed up the fact that observers often exaggerate or minimize certain spatial dimensions. Thus, conditions may lead an observer to enhance the vertical at the expense of the horizontal or to highlight the left half of a perceived space as contrasted to the right half. Takala found indications that individuals may differ consistently in their mode of anisotropic distortion over a range of situations. There may be individual tendencies to impart spatial directionalities or vectors to experiences without any reality basis for doing so. This paper concerns itself with developmental sex differences in rightleft anisotropy. In speculative discussions of sex differences it has sometimes been suggested that the left is associated with a feminine orientation and the right with a masculine orientation. A spatial asymmetry is posited in terms of the difference in masculinity-femininity assigned to the right as compared to the left sectors of space. Indeed, Sandstrom (xo) and Bennett (x) have both found indications that in adjusting a luminous rod to the vertical in a dark room adult women are inclined to manifest a left, and adult men a right, bias in their judgments. Wapner and Werner (12) have reported that up to the age of io there is no real difference between the sexes in the right-left directionality of constant errors made while adjusting a luminous rod to the vertical. However, they noted that in the age range 10 to 17 boys significantly more often located the vertical to the right, and girls to the left, of true vertical. Chateau (4) has observed in preadolescents and adolescents that boys are more likely than girls to prefer right turns in a maze.