Fig. 3.

Mean pupil dilation (i.e., change in pupil diameter from the first 500 ms to the second half of the trial) for faces (top) and cartoons (bottom), plotted in (A) as a function of stimulus. Error bars indicate ±1 SE. Raw change in pupil diameter plotted in (B) as a function of time. NB: Face videos elicited larger dilations despite the fact that they were slightly more luminous, on average, than cartoon videos (pupil constriction would be expected if the pupillary changes were simply due to a light-reflex response).