Figure 5.

The effect of an increase in stimulus radiance. (a) Group average pupil responses (± SEM) for each stimulus condition from session 3 (n = 21 subjects). (b) Group average responses from session 3 (background luminance for Mel and LMS were ∼270 cd/m² and ∼90 cd/m², respectively) in dotted lines are plotted on top of group average responses from sessions 1 and 2 combined (n = 30 subjects; background luminance for Mel and LMS were ∼110 cd/m² and ∼40 cd/m², respectively). Although the change in stimulus radiance did not alter the pupil response to the silent substitution stimuli, the pupil response to the PIPR stimuli was increased.