Handedness, health and cognitive development: evidence from children in the National Longitudinal Survey of Youth

Using data from the child supplement of the US National Longitudinal Survey of Youth, and fitting three-level random-effects models of child health and cognitive development, we test whether left-handed children have different outcomes from those of their right-handed counterparts. The health measures cover both physical health and mental health, and the cognitive development test scores span vocabulary, mathematics, reading and comprehension. Overall we find little evidence to suggest that left-handed children have a significantly higher probability of experiencing injury, illness or behavioural problems. In contrast, we find that lefthanded children have significantly lower cognitive development test scores than right-handed children for all areas of development with the exception of reading. Moreover, we find no strong evidence that the left-handedness effect differs by gender or age.