Hemispheric asymmetry as a function of handedness: perception of facial affect stimuli.

Hemispheric asymmetry in 14 left- and 14 right-handed persons shown tachistoscopically presented emotional stimuli to left and right visual fields was examined using a forced-choice, reaction-time paradigm in which subjects were asked to identify positive and negative faces. Neutral faces were included within the two-alternative forced-choice paradigm. Reaction time and response-bias measures were recorded. Analysis indicated differential lateralization for left-handed and right-handed subjects with respect to neutral affective stimuli. While right-handed subjects' perceptions of neutral stimuli remained consistent across visual fields, left-handed ones identified neutral stimuli as more positive (happy) when presented to the left visual field and negative (angry) when presented to the right visual field. Implications for differential lateralization patterns among left- and right-handed adults are discussed.