Fig. 5.

Panel A: Grand-average pupil dilation responses (PDRs) for emotional novel sounds, neutral novel sounds, and standard sounds for each age group. Novel sounds evoked statistically significantly increased PDRs compared to standard sounds in both groups. Panel B: Mean reconstructed component time courses (component loadings scaled by standard deviation (SD) and component scores per condition and age group; strong colors; mm) reflecting the portion of the recorded waveform accounted for by each component. The chronologically later component explains most variance and is discussed to reflect the activity of the sympathetic pathway of the autonomic nervous system. The earlier component is considered to reflect the activity of the parasympathetic pathway of the autonomic nervous system. The grand-average PDRs (transparent colors) were added for reasons of convenience and are identical to Panel A. Panel C displays mean PCA component scores (error bars show the 95 % confidence interval) that reflect the amplitudes for each sound type and group. Emotional novel sounds elicited statistically significantly increased amplitude for the late component only. Note. ***p < .001 (t-test).