Left-handers and right-handers compared on performance and preference measures of lateral dominance

Ninety-three right-handed and 53 left-handed adults were compared on a range of performance and preference measures of handedness and footedness. Performance measures included tests of accuracy, speed, and strength. Non-parametric statistical procedures were used to determine whether left-handers (LHs) were less lateralized than right-handers (RHs), and whether distributions for LHs were the mirror images of those for RHs. On performance measures, the distributions for LHs and RHs were generally normal and similar in central tendency, shape, and range. However, on preference measures, distributions were J-shaped, and LHs were significantly less lateralized and more widely dispersed than RHs. Correlations among performance measures were generally low for all subjects. Sex and familial left-handedness did not significantly moderate the responses of these right- and left-handers on performance or preference measures of lateral dominance.