Abstract

This study was intended to investigate the connection between emotional stimuli and brain activities by the use of ERP which is one of the central measures in psychophysiology. In this study, the affective primacy model was tested based on the LeDoux's neurophysiological model through the ERPs. As the subliminal ERP was assumed to be a direct brain index of unconscious processes, a comparison between the subliminal ERP and supraliminal ERP was made in order to examine the unconscious processing of emotional stimuli. 17 males and females participated in the experiment. The independent variables were three factors including stimulus types (emotional picture vs. neutral picture), sites(F3, F4, Cz, P3, P4), and presentation time(subliminal vs supraliminal). The results were differentiated by sex. Male subjects differentiated the stimulus types, and in addition, showed a left frontal superiority even for the subliminal condition. Even though female subjects showed a differentiated effect for the subliminal emotional stimuli, they failed to show frontal superiority, instead, the pervasive activation over the left hemisphere was menifested. Moreover, female subjects characteristically showed a lateralization effect including both the frontal asymmetry and the parietal asymmetry for the supraliminal emotional stimuli. They showed the frontal asymmetry, however, accompanied by the parietal asymmetry simultaneously. The results suggest lateralization effects rather than localization effects for the emotional stimuli. Some extraneous factors like sexual defenses and attitudes about the sexual stimuli should also be taken into consideration in discussing the overall results.