Orienting of auditory spatial attention: effects of a lateralized tone cue.

Mondor and Bryden [8] (Neuropsychologia 29, 1179-1190, 1991) reported that the normal Right Ear Advantage for the identification of verbal material presented dichotically could be largely eliminated if subjects were cued to attend to and report from only one ear on each trial. In these experiments, the ear to be attended was cued by presentation of a tone to that ear only prior to each dichotic trial. The present series of studies were undertaken to determine whether this lateralized tone cue exerted its effect by orienting attention or by alerting the subject of the forthcoming trial. Results revealed that for both the right and left ears the facilitating effect of the cue was dependent on the accuracy of the location information it conveyed. Thus, the precueing technique originally employed by Mondor and Bryden as a means of controlling the contribution of attention to ear advantages was validated. It is concluded that the precueing technique provides a powerful means for specification of the extent to which attentional factors and hemispheric functional capabilities contribute to ear asymmetries.