Fig. 3.

Correlation matrix showing the relationship between the baseline arousal indices. Histograms showing the distribution of each variable are shown diagonally on the 1:1 line. Below this line, scatterplots show the relationships between variables. Linear regression lines have been drawn in black. Above the 1:1 line, the Pearson’s product moment correlation shows the relationship between the two variables. The stars show the significance levels of the bivariate correlation: **p(2-tailed) < .01, *p < .05, and (*)p < .10. The autonomic measures used to compare with the pupil size recording have been obtained from a different section of the testing battery, as described in Section 3.