Cognitive sex differences have been demonstrated in humans: men usually outperform women on spatial ability (Linn & Peterson, 1985; Gladue et al., 1990; Mann et al., 1990; Gouchie & Kimura, 1991; Gladue & Bailey, 1995; Halpern & Tan, 2001; Tan et al., 2003a, b; Herlitz & Lovén, 2009); women outperform men on verbal tasks (Hyde & Linn, 1988; Mann et al., 1990; Halpern & Tan, 2001; Tan et al., 20...