Pupil dilation when viewing strangers: Can testosterone moderate prejudice?

Undergraduate students, 27 white and 27 black, provided saliva samples for testosterone assay, completed measures of prejudice, and viewed pictures of black and white target persons. Pupil dilation was measured continuously while participants viewed the pictures and thought about meeting the persons whom they were seeing. Testosterone interacted with prejudice, such that prejudiced individuals who were low in testosterone showed large pupil dilation and prejudiced individuals who were high in testosterone showed small pupil dilation. The interaction of testosterone with prejudice in affecting dilation was not related to the race either of the participant, or of the target being viewed.