The relationship between laterality and numerical and spatial ability

Hypotheses derived from right shift theory concerning the relationship between laterality and mathematical ability were investigated. This was done by dividing a group of 129 subjects into subgroups with presumably different distributions of the rs ++, rs +- and rs -- genotypes on the basis of their manual skills and then assessing their numerical and spatial abilities. No relationship was found between laterality and ability when the group as a whole were considered, but some marginal effects were found for numerical ability when data for a subgroup of 96 young female subjects were analysed separately. The results did not, however, conform to the predictions of right shift theory.