Individual differences in neurobehavioral measures of laterality and interhemispheric function as measured by dichotic listening

This article presents analysis of dichotic listening performance in 57 heal thy men and women aged 20 to 72 years. The data are presented as a means to cover 2 theoretical issues relevant to the biobehavioral study of laterali ty and interhemispheric relations. First, the sensitivity of dichotic liste ning performance to factors such as sex, age; and their interactions was ex amined. Dichotic listening asymmetry scores were found to vary as a functio n of sex, age, handedness, and family history of developmental language dis orders. The effects of sex and age were then explored in relation to a comp arison of nonforced and unilaterally focused test conditions. The results s uggest that even within a healthy, normative sample of human participants, individuals vary not only in their underlying perceptual asymmetries for au ditory input, but also in the manner in which such asymmetries interact wit h other higher order cognitive functions.