A reassessment of the time-sharing paradigm with ANCOVA.
The purpose of this note is to follow up on the suggestion by Willis and Goodwin (1987) (Neuropsychologia, 25, 719-724) that analysis of covariance is the proper statistical control to eliminate the confound provided by the "initial values problem" inherent in the time-sharing paradigm. The discrepancy between baseline tapping speed of the dominant versus nondominant hand can affect concurrent tapping disruption rates independently of laterality factors. A re-analysis of previous time-sharing data showed that significant laterality main effects and interactions as shown by ANOVA are eliminated with ANCOVA procedures. Thus, when the initial-values problem is statistically controlled, the laterality effect of asymmetrical hand disruption disappears. This result seriously questions the continued use of the time-sharing paradigm as a behavioral index of language lateralization.
Sussman
H M
HM
University of Texas at Austin.
D000328:Adult; D000704:Analysis of Variance; D001288:Attention; D004292:Dominance, Cerebral; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009048:Motor Skills; D014705:Verbal Behavior