Dichotic ear preference of affective speech

Includes bibliographical references (pages 49-56)Experiments on dichotic listening have suggested that the perception of verbal stimuli depends on unilateral processors located in the dominant hemisphere. The purpose of this study was to see if affective speech is processed in a similar way to other verbal stimuli. The claim was that the automatic and propositional levels of speech are processed differently. While the propositional level of speech is processed only in the left hemisphere, the automatic level of speech is processed in both hemispheres. This hypothesis is based on evidence from aphasia, in which, the automatic language is often preserved while propositional speech is lost. A dichotic listening test composed of 20 pairs of emotional vs. neutral words was administered to 22 adults. Normal hearing was varified by means of the Speech Reception Threshold test. Subjects were first given the SRT test, then a dichotic nonsense syllable test and then a dichotic test of emotional vs. neutral words. All dichotic tests were administered at 70 db above the threshold for the SRT words. Data analysis revealed a REA for all words presented. To further analyze the ear advantage for the two types of words presented, a two way analysis of variance (right vs. left ear, emotional vs. neutral words) was performed. It revealed a significant REA and a significant advantage for emotional words. In addition, an interaction between the variables was also demonstrated