Cognitive and affective relations in perception of auditory stimuli in the presence of music.

Abstract

The present study explores the parallel between the affective and the masking effect of music on the auditory perception under passive and selective listening conditions. Seven subjects took part in the experiments. An auditory frequency discrimination task (target 1000 Hz tones, probability 20%; standard 1550 Hz tones) in a dichotic listening environment was employed. Music was presented binaurally through the same headphones. The investigation of the masking effect of music is extended by reporting the interaural and the interhemispheric asymmetry as revealed by the background EEG activity and the N1-P2 responses of the ERPs, recorded from C 3 and C 4 derivations. Connotative meaning of the auditory stimuli was measured over five scales of adjectives on a semantic differential. The variations in the background EEG activity and the N1-P2 amplitude, as well as their interhemispheric distribution under the passive condition with music, describe a brain state of hearing through relaxation with rather positive connotative meaning. Under selective listening the N1-P2 responses demonstrated a right ear/ left hemisphere advantage that was further enhanced with music. The perceived positive emotionality under the selective listening was reduced as compared to the passive condition, without any ear-attended differences. An attention-related increase of the N1-P2 responses with music was found over the right hemisphere, and particularly, in the left ear, indicating a greater processing effort under the more difficult discrimination. These findings suggest that the connotative meaning depends on the task performed. The most relevant scale for rating the affective meaning of tonal sequences in the presence of music was found to be the category pleasant-unpleasant.