Predictability of hand skill and cognitive abilities from craniofacial width in right- and left-handed men and women: Relation of skeletal structure to cerebral function

Recently, a family of homeobox genes involved in brain and craniofa-cial development was identified. In light of this genetic background, we hypothesized that some functional characteristics of human brain (hand skill, cognition) may be linked to some structural characteristics of human skull (e.g., craniofacial width) in humans. Hand preference was assessed by Oldfield’s Handedness Questionnaire. Hand skill was mea-sured by Peg Moving Task. Face width was measured from the antero-posterior cephalograms (x-ray) using right (R) and left (L) zygomatic points. Intelligence “g ” was assessed by Cattell’s Culture Fair Intelli-gence Test; the perceptual-verbal ability was assessed by “Finding A’s Test”; the spatial ability was assessed by the mental rotation task, in right- and left-handed men and women. The percentages of right-