Do visual field asymmetries intercorrelate?

Lateralized word and bargraph recognition tasks were presented to 22 right-handed and 15 left-handed subjects. The correlation between the opposite reaction time asymmetries for the tasks was significant, and indicated that individual subjects generally showed strong lateralization for one task and weak lateralization for the other. The results are viewed as inconsistent with models of individual differences in hemispheric function that stress strong hemisphericity, lateralization strength, or independent functions. However, they are consistent with a model stressing weak hemisphericity. Also potentially consistent with the results is the neurodevelopmental theory of Geschwind and Galaburda (Cerebral Lateralization: Biological Mechanisms, Associations and Pathology, MIT Press, Cambridge, Massachusetts, 1987), if it is assumed that the lateralized functions reflected by the tasks are subserved by homologous anatomical areas. Compared to right-handers, left-handers tended to produce a smaller correlation between the tasks, as well as weaker hand preferences, and smaller and less reliable field asymmetries.