Developmental changes in the pattern of ear asymmetry as revealed by a dichotic listening task

Dichotic listening performance in 63 right-handed and 91 left-handed school-age children at various age levels were examined. Contrary to most previous research, a developmental change in the pattern of ear asymmetry was found most pronounced in right-handers. An increasing proportion of children with right-ear advantage was found across age at the same time as the magnitude of this ear asymmetry decreased with increasing age. These results, however, were found only when the number of correct responses from the left and right ear were treated as relational data, and the pattern of ear asymmetry was calculated for each subject individually. When calculated as group means for each ear separately, the common finding of no developmental change in the pattern of ear asymmetry was revealed. The results are discussed in relation to research on myelogenetic correlates in linguistic development and on research concerned with different subgroups of dyslexia, as well as previous studies of developmental aspects of dichotic listening. Against this background it is suggested that a two-dimensional theory must be used in interpreting developmental data in dichotic listening.