The Nature of the Age Decrement in Performance on Dichotic Listening Tasks

Abstract

Previous experimental work has shown that when subjects of different ages are presented with a series of dichotic digits (as two simultaneous half-sets, one to each ear) there is an age decrement in the reproduction of the second half-set. It has been suggested that this result is due to the second half-set being involved in a short-term storage process and that this process declines in efficiency with age. It seemed equally possible however that the result was due to perceptual or attentional factors rather than memory factors. Two experiments were thus carried out in an attempt to specify the nature of the decrement. In the first, instructions as to which half-set to reproduce first were given before presentation of the digits. In the second experiment attention was equally divided between the ears by giving these instructions after presentation. An analysis of types of error in the first experiment suggested that attentional factors were more important but from a similar analysis in the second experiment it was concluded that memory factors were largely responsible for the age decrement.