Faglioni, Spinnler, and Vignolo (1969)
FAGLIONI, P., H. Spinnler, and L. A. Vignolo. “Contrasting Behavior of Right and Left Hemisphere-Damaged Patients on a Discriminative and a Semantic Task of Auditory Recognition.” Cortex 5/4 (1969): 366-89.
Reports on experiments designed to test for differences in performance between left-brain-damaged, right-brain-damaged, and control subjects on a group of five tests. The main tests of interest to the current program are the “meaningless sounds discrimination test,” and the “meaningful sounds identification test.” The meaningless sounds test consisted of blended sounds derived from 2 separate radio sound-effect tracks. The meaningful sounds consisted of sounds normally identified with a specific source, i.e. meowing: a cat; bleating: a goat. On the former, subjects were presented with two stimuli, and asked whether they were the same or different. On the latter, subjects were asked to name (or point to a picture, in the case where voluntary speech was impaired) the logical source of each sound. Neither of these tests used human vocal sounds. However, it was found that discriminations within each of these two groups was subtended by a different hemisphere.
It was assumed that performance on the Meaningless Sounds Discrimination Test reflected the ability to discriminate differences among acoustic patterns, while performance on the Meaningful Sounds Identification Test reflected the ability to identify the exact meaning of naturally-occurring sounds. (371)
It is apparent that failure on each test was specifically associated with damage to a different hemisphere. On the Meaningless Sounds test, the left hemisphere-damaged group did as well as the controls, while the performance of the right group was significantly inferior to that of the other two groups. The reverse occurred with the Meaningful Sounds Test, on which the right brain-damaged group obtained the same mean score as the controls, while the left brain-damaged patients performed significantly worse that the other two groups. (374)
Significantly, it was found that aphasic patients, although language-impaired performed equal with the controls in terms of the meaningless sounds test. This showed that their deficits were not due to damage to any central auditory processor, but rather specific to the aligning of sounds with meaning. Likewise, the fact that the right-hemisphere patients performed normally on the sound source identification task, but had difficulty comparing novel and unfamiliar sounds, suggests that there are redundant mechanisms at work under different auditory situations.
