Cognitive Ability and Hemispheric Indecision - Two Surpluses and a Deficit

This paper re-examines a finding by Crow et al. (1998) showing that equal skill of right and left hands – hemispheric indecision - is associated with deficits in cognitive ability. This is consistent with the idea that failure to develop dominance of one hemisphere is associated with various pathologies such as learning difficulties. Using the same data, the British National Child Development Study, we find strong evidence of both surpluses and a deficit associated with this indecision. So no general association between indecision and cognitive ability can be drawn from this data.