The development of auditory figure-ground discrimination and ear asymmetry under nonaural stimulus presentation

The development of auditory word discrimination ability in normal male children has been investigated. 56 school-children (14 from kindergarten and 14 each from second, fourth and sixth grades) were asked to discriminate 50 single-syllable words presented against four levels of background noise (0, +10, +20, and +30). Age, noise level, and ear were all significantly related to auditory word discrimination scores. The results of the study show that with increasing age there is increased ability to discriminate words in the presence of noise. However, although the older the child the greater his ability to discriminate, a far greater effect than age on discrimination is the signal-to-noise treatment level, a finding which suggests that knowledge of the treatment condition may be a better predictor of auditory discrimination scores than a child's age. An additional finding was a general right-ear superiority in the presence of noise, most consistently found under the 0 signal/noise condition for children in kindergarten and in second and fourth grades.