Culture and brain organization.

The second half of the twentieth century has seen an explosion in research developments in the area of cognitive neuropsychology. One of the sources of this explosion are the spectacular findings showing the perceptual and performance asymmetries of the disconnected hemispheres of the split-brain patients from Roger Sperry’s lab, which spawned enormous interest in hemispheric specialization. Studies of the laterality patterns in the physiological substrate and the behavior of brain-damaged and healthy participants have resulted in a general picture of hemispheric abilities—that is, we have a model of a modal brain with a map of its functional architecture. The study of individual differences in brain laterality has focused on specific biological factors such as handedness and sex and has begun to delimit their effects on the organization of cognitive abilities, performance asymmetries, and morphological differences in brain structures (e.g., Clarke, Lufkin, & Zaidel, 1993; Eviatar, Hellige, & Zaidel, 1997). In this essay I would like to argue that as a complement to biological characteristics, the study of the effects of learned behaviors that constitute culture on brain organization can be crucial in delimiting the manner in which higher cognitive processes are related to brain organization. This is a somewhat Whorfian view, in which the search is for crucial dimensions of culture that interact, or co-occur with systematic differences in functional architecture of cognitive functions in the cerebral hemispheres. Language is the most promising dimension, because linguistic and psycholinguistic models allow us to talk about both similarities and differences between languages in principled ways. Focusing on language is useful because it is the faculty about which we know the most, and it enables us to better delineate the seam between organizational principles that are or are not susceptible to different learning environments and strategies. The problem with the modal model of the functional architecture of the