HEMISPHERIC ASYMMETRY IN EARLY LIFE: TACTILE PROCESSING

The present series of studies are designed to explore the early development of right hemispheric specialization for tactual processing, an area of research which, in infants and young children, has received scant attention. These studies build upon our earlier work in which, using a newly developed measure of cross-modal transfer we found a right hemispheric superiority for tactual procesing of form in children as young as two years of age. Since cerebral lateralization is a particularly salient aspect of information processing among adults, understanding how and when young children develop similar asymmetries may contribute to our understanding of early brain function. Six studies of tactual processing are designed to assess (1) the replicability of our initial findings in right-handed children aged 1-5 years, the likelihood that the left hand advantage found initially reflects a right hemisphere advantage for processing forms globally, as spatially organized wholes, and the extent to which tactual processing is similarly lateralized in left handers, (2) the role of differential tactile thresholds and finger dexterity in the left hand advantage, (3) the degree to which hemispheric asymmetries increase from 1- to 2- years, a period singled out for intensive study in view of our initial failure to find any indication of hemispheric specialization in infants as young as one year of age, (4) the specificity of the interference found in our initial studies when music was introduced during palpation, (5) the developmental course of lateralization for speech and music processing (medoly recognition), and (6) the extent to which the presence of asymmetries may be underestimated in the cross-modal paradigm. The long range goal of this research is to understand better (a) the degree of lateralization present early in life for tactual processing (b) developmental changes or continuities in functional cerebral organization and (c) the implications of early asymmetries for perceptual and cognitive functioning.