Acculturation and the lateralization of speech in the bilingual Native American

Previous reports have suggested that bilingual Native Americans differentiate cognitively in processing their sociologically dominant and non-dominant language. Specifically, there is some evidence that receptive speech functions may be lateralized to the right cerebral hemisphere. To test the notion that this differential specialization may be due to socio-cultural influences, receptive and expressive speech lateralization was examined in a population of acculturated bilingual Native Americans. An analysis of dichotic listening and time-sharing asymmetries indicated that despite evidence for an initial appositional tendency, the Native American subjects were lateralized to the left cerebral hemisphere for both receptive and expressive speech. It is proposed that shifts in the attended perceptual field occur as Native Americans mature perhaps due to an increasing familiarity with a second culture and more propositionally oriented language.