The influence of attention on the dichotic REA with normal and learning disabled children.

Recently, Mondor and Bryden (Neuropsychologia, 29, 1179-1190, 1991; Percept. Psychophys. 52, 393-402, 1992) developed a lateralized cueing technique which appears to be a more powerful method than is the forced-attention technique (Bryden, 1978) of controlling the contribution of attentional biases to auditory perceptual asymmetries. This lateralized cueing technique was used to determine the influence of attentional biases on perceptual asymmetries obtained for normal and specific learning disabled (LD) children. Subjects were instructed to attend to, and report from, only the ear in which the cue sounded. The interval between the onset of the cue and the onset of the dichotic trial is varied so as to control the amount of time available to subjects to allocate attention to the cued ear. Results indicated that, for normal children capable of performing the task at a better than chance level, a large REA apparent at 150 msec Stimulus Onset Asynchromy (SOA) was attenuated at longer cueing intervals (450 and 750 msec SOA). For LD children, the magnitude of the initial REA appeared to be attenuated at 450 msec SOA. Thus, these data demonstrate that for normal children as well as for children with specific learning disabilities, attentional factors may contribute to the magnitude of the REA.