Lateral asymmetry of positive and negative emotions.

This reaction time study examined whether the left and right hemispheres are differentially specialized to process positive and negative affect respectively in adult females and males. Either happy or sad facial expressions of emotion were presented simultaneously with neutral facial expressions to the two visual fields. Happy faces were responded to more rapidly in the left visual field-right hemisphere with no visual field differences for sad faces. Females were superior to males when emotional facial stimuli were presented to the left visual field and were more accurate in recognizing sad faces compared to happy ones.