Laterality Effects in Dichotic Listening

Abstract

THE hypothesis of a laterality effect in dichotic listening (D-L) has been challenged by Oxbury, Oxbury and Gardiner¹. The authors concluded that the right ear superiority may have been the result of an attentional bias toward the right ear when free recall methods are used. This argument is based on the following data. When different half-spans of digits are presented in simultaneous pairs to each ear through stereo headphones, and at rapid rates, Ss tend to recall the messages (under free recall) by an ear order of report rather than by a temporal order of report². Furthermore, information presented to the ear reported first (perceptual channel) is more accurately recalled than information presented to the ear reported second (delayed or storage channel). If therefore Ss, under free recall, tend to report more often from the right ear first, an ear asymmetry in favour of the right ear would be expected because of the failure to control for a bias in the order in which messages are reported. This hypothesis also assumes that the right ear superiority should disappear when the order of report is controlled^1,3.