Relationships among multiple task asymmetries. II. A large-sample factor analysis

Samples from published and unpublished factor analytic studies of multiple task asymmetry are combined to produce a large-sample factor analysis of 10 measures, prescreened for significant asymmetry and acceptable reliability, from 9 lateralized tasks. A full correlational matrix is presented, with task pairings having sample sizes ranging from 103 to 479 (mean N = 290). Both significant positive and significant negative correlations between measures are found. Extraction and oblique rotation of five factors fails to reveal any evidence of a global relationship among lateral difference measures, and principal-components analysis likewise fails to reveal a component to which all measures correlate positively. However, evidence for local structure is found. Results are interpreted in terms of dissociable hemispheric processes, and consideration is given of the possible existence of modality-specific characteristic perceptual asymmetry and of single versus multiple determination of lateral differences.