Table 2.

Linear Mixed-Effects Models Probing the Relationship Between Age Group, Arousal Condition, and Pupil Dilation on Subjective Arousal Ratings for Sound Clips

Predictors	Estimate	S.E.	Wald’s 95% CI	t-value	p-value
Intercept	1.66	0.08	1.50, 1.82	20.46	< .001
Age	−0.06	0.08	−0.22, 0.10	−0.70	0.484
Arousal	2.16	0.029	2.10, 2.22	72.95	< .001
Pupil dilation	−20.12	64.24	−145.98, 105.74	−0.31	0.754
Age × Arousal	−0.28	0.03	−0.34, −0.23	−9.59	< .001
Age × Pupil dilation	1.95	64.24	−123.91, 127.81	0.03	0.976
Arousal × Pupil dilation	294.39	90.28	117.45, 471.35	3.26	0.001
Age × Arousal × Pupil dilation	25.36	90.28	−151.59, 202.34	0.28	0.779

Note. 95% confidence intervals were computed using confint.merMod function from the lme4 library in R. Age (1=young, −1=older), arousal (1=arousing, 0=non-arousing), and pupil dilation to sounds were modeled as fixed effects. The participant intercept was modeled as a random effect.