Right and left handedness defined: a multivariate approach using hand preference and hand performance measures.

Abstract

Writing hand was highly correlated with scores from a hand preference inventory. In contrast, the use of a single hand performance measure, finger tapping or pegboard, did not always correctly classify an individual as right- or left-handed. However, when both of these hand performance measures were used together. individuals were correctly classified as right- or left-handed. Using this approach, two approximately non-overlapping groups, right- and left-handers, emerged. Thus, handedness is probably not a one-dimensional trait or behavior, and must be defined using multiple measures that assess different aspects of hand preference and performance. The implications for hemispheric specialization of language and neural asymmetry research are discussed.