Ear advantage in dichotic listening and head size; model considerations

Abstract

The development of ear advantage in children seems to be established by age five. As children mature, binaural accuracy dramatically improves which is presumably due to increased capacity of the speech processor. At age five, the mean head size is 50.5 cm; and at one year it is 45 cm. Two models are postulated to explain dichotic listening are (1) a passive model suggesting that stimuli coming from the right ear arrives at the left hemisphere before information from the left ear and the one ear processing may interfere with the contralateral ear input under some conditions: and (2) an active model suggesting the verbal left hemisphere receives information from the right side of space and spatial localization and selective attention are critical. Two six‐year‐old females with normal intelligence and head sizes five standard deviations below the mean were given CVs with 0‐ and 30‐ms leg onsets through earphones and loudspeakers. The concepts of processing speed (mylinization) and capacity (dendritic aborization) are discussed in relation to the models in terms of redundancy, accuracy, and errors.