The sociology of emotions was formed at 1970's in U.S.A. in order to analyze emotional behavior. It uses the concept of 'emotion norms' that distinguish just emotions from unjust ones. In modern society, emotion norms prevent persons that feel unjust emotions from expressing those emotions.
'Emotion system' is external to law system that presumes persons who behave rationally. But the law system has to concern emotion system because both relate social order. There is a route that social just emotions reflect the law system (ex, revenge emotions, family emotions). And there is a route that the law system provides justice of emotions and makes people give up the unjust emotional expressions.
Recently, 'the emotional naturalism' is spreading over the Japanese society, that is the idea the emotional expressions provide people the true self. Consequently, the emotion norms become weak, and the opportunities of bare emotional expression are increasing. That trend leads the increase of crimes by unreasonable motives, reinforcement of revenge emotions of survivors and the increase of hatred between family members. So the gap is appearing between law system and emotion system.
