Abstract: The humans experience emotion at apparently distinct valence strength which, however, is out of the research focus until recent years. Through manipulating the valence strength of emotional stimuli, we systematically addressed the human susceptibility to the valence strength of emotional stimuli from the perspectives of the emotion susceptibility itself, the emotion impact on higher cognition and the individual specialty. The results showed that the human brain is more sensitive to the valence strength of unpleasant versus pleasant stimuli, which may be associated with the emotion alerting function of the right amygdale/hippocampus. Secondly, consistent with the above findings, unpleasant emotion induction of diverse strength impacts higher cognition, such as novelty processing, target detection and behavioral inhibitory control, differently at each stage of the processing stream. Thirdly, there are significant individual differences in brain susceptibility to emotional events. Compared to males, females are more susceptible to mildly unpleasant events. Moreover, compared with ambiverts, extraverts are more susceptible to pleasant stimuli regardless of emotion intensity, and are less susceptible to unpleasant stimuli of decreased valence strength.

Key words: emotion, susceptibility, valence strength, gender, extraversion