Music Valence Can Affect Dichotic Listening Performance

Background and Aim: Music can regulate the activity of brain structures that play a significant role in emotions. The perceived emotion techniques such as dichotic listening clarify the relationships between auditory emotional stimuli and hemispheric asymmetries in the auditory modality. We examined the impact of pleasantness/unpleasantness of music by Acceptable Noise Level (ANL) as a subjective measure of listeners’ willingness to accept background noise. 
Methods: In this study, 32 participants rated their pleasantness with about ten songs; then, we considered the effect of preferred pleasant and unpleasant music on dichotic music listening and acceptable background noise. There were six forced attention conditions to calculate ANL, followed by measuring the most comfortable level and background noise level for each condition. 
Results: The pairwise comparison analyses revealed significantly higher ANL in forced attention to pleasant music than to speech (p<0.004) and unpleasant music to the left ear (p≤0.05). The mean ANLs difference in 2 groups of right ear advantage and left ear advantage showed significant intra-hemispheric differences in the forced pleasant music attention than the forced unpleasant music attention conditions (p<0.007), and forced speech conditions (p=0.001), only in the left ear advantage group. In addition, the interaction between conditions and groups showed interhemispheric asymmetry. 
Conclusion: Music valence and intra- and interhemispheric differences can affect the ANL dichotic processing and, consequently, lower noise tolerance (higher ANL) in forced pleasant music attention conditions. 
Keywords: Acceptable noise level; dichotic listening test; music valence; functional laterality