Fig. 1
From: Mothers’ pupillary responses to infant facial expressions
Examples of infant face stimuli from each stimulus category defined by the intensity and valence of the facial expression of emotion. Randomized pixels (on the right), derived from all face stimuli were used as a pre-stimulus display. In the control experiment (Experiment 2) randomized face pixels, derived from each face stimulus individually, were used in place of the face stimuli in the “non-face” condition