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.

This study was designed to determine if three diagnostic groups of Navajo children differed on intellectual dimensions as measured by the WISC-R. Subjects had been previously diagnosed by state certified professionals and were identified as nonhandicapped (NH) ( N = 113), educationally disadvantaged.(ED) ( N = 189), and learning disabled (LD) ( N = 150). N H group means on all WISC-R variables were significantly higher than the LD group means. The ED and the LD group means were similar on &he verbal measures, but the LD group scores were lower than the ED group scores on performance measures. The N H group demonstrated intellectual abilities and deficits similar to those reported for other primary-grade Navajo children who had not been referred for suspected handicapping conditions.