Body asymmetry and intellectual pattern

Abstract

Young men and women who had made self-inspections of direction of testicular-or breast-size asymmetry, were evaluated on a battery of cognitive tests. Tests were categorized as Masculine (generally performed better by men), Feminine (better by women), or Neutral (favouring neither). Men and women with larger right sides performed relatively better on Masculine tasks, whereas those with larger left sides performed relatively better on Feminine tasks. The findings are interpreted to mean that gonadal/somatic asymmetry may be a marker of early development of certain sexually dimorphic neural systems, whether or not it directly reflects brain hemispheric asymmetry. The data suggest a significant biological contribution to intellectual pattern.