Hemispheric differences in the perception of positive and negative faces.

Thirty-two right-handed subjects (15 males and 17 females) participated in a study investigating the effects of the perception of positive and negative emotional stimuli on choice reaction time. Slides of faces showing positive (happy, surprise) or negative (anger, disgust, sadness) affect were presented via a tachistoscope to either the right or left visual field. A 2 X 2 X 2 X 2 mixed analysis of variance with repeated measures over the factors of hand used by visual field by affect across sex of subject revealed a main effect for visual field (with slightly faster responses to stimuli presented in the right visual field) and a strong affect by visual field interaction with positive facial slides identified more quickly than negative facial slides when presented to the right visual field.