Shared and distinct mechanisms of individual and expertise-group perception of expressed arousal in four works

We compare the continuously perceived expressed arousal of four three-minute musical extracts (three electroacoustic, one acoustic - for piano), for inter-individual and inter-expertise-group differences. Participants are electroacoustic musicians, generalist musicians, and non-musicians. Time series analysis methods are used, including cross-sectional time series analysis. The prevalence of stasis in individual responses is described. Then we determine whether group average responses differ between groups. Finally we define the inter-individual variation in responses, and how this impacts the detection of group differences. We find that inter-individual variations in each expertise group are large, and can overwhelm inter-group differences. There are substantial variations between the pieces, related to the extent of acoustic intensity changes, and distinguishing the instrumental and electroacoustic works. Nevertheless, a single optimised "parent" model of the influence of acoustic profiles on perceived arousal has predictive power for all four pieces. This includes acoustic intensity, spectral flatness, and autoregression. The pieces share mechanisms, and show differences, in how they evoke perceptions of expressed arousal.