Subclassification of non-pathological left-handers poses problems for theories of handedness

The throwing performance of 104 right-handers, and 96 left-handers with inconsistent and consistent hand preferences, as classified by the procedure used by Ponton (Neuropsychologia 25, 305-311, 1987), was examined. Left-handers with inconsistent hand preference write with the left, tap faster with the left, and perform better with the left on the Purdue Pegboard task (Peters and Servos, 1989), but are stronger in the right hand and throw better with the right hand. In the other two groups, strength and skill activities are laterally congruent. This poses difficulties for theories of handedness.