POSTURAL ASYMMETRIES AND LANGUAGE LATERALIZATION IN HUMANS (HOMO-SAPIENS)

Is hemispheric specialization for speech more closely related to left hemisphere specialization for manual skill and sequencing, as is usual ly supposed, or to control of asymmetries in whole body posture, as re cent findings of right-handedness in nonhuman primates suggest? This q uestion can be evaluated in the 10% of humans who have mixed handednes s and footedness. Footedness entails postural asymmetry, and persons w ith mixed limb preferences often prefer the hand ipsilateral to the pr eferred foot in asymmetrical actions for which whole body postural adj ustments are obligatory (e.g., throwing). The dichotic listening test, an indicator of language laterality, was administered to 4 groups of 48 persons with the 4 possible combinations of hand and foot preferenc e. As in 2 past studies, language lateralization was somewhat more str ongly related to postural asymmetries than to asymmetries in manual sk ill and sequencing.