Processing emotional stimuli: Comparison of saccadic and manual choice-reaction times

We compared the speed of discrimination for emotional and neutral faces in four experiments, using a forced-choice saccadic and manual reaction time task. Unmasked, brief (20 ms) bilateral presentation of schematic (Exp. 1) or naturalistic (Exp. 2) emotional/neutral face pairs, led to shorter discrimination of emotional stimuli in saccadic localisation task. When the effect of interference from emotional stimuli is ruled out by showing a pairing of the emotional or neutral face with an outline face, faster saccadic discrimination was obtained for fearful facial expression only (Exp. 3). The manual discrimination reaction time was not significantly different for emotional versus neutral stimuli. To explore the absence of a manual RT effect we manipulated the stimulus duration (20 ms vs. 500 ms: Exp. 4). Faster saccadic discrimination of emotional stimuli was observed at both durations. For manual responses, emotional bias was observed only at the longest duration (500 ms). Overall, comparison of saccadic and manual responses shows that faster discrimination of emotional/neutral stimuli can be carried out within the oculomotor system. In addition, emotional stimuli are processed preferentially to neutral face stimuli.