2008 年 16 巻 1 号 p. 25-35
This paper proposes an evolutionary hierarchical hypothesis that feelings in humans consist of four levels of emotion based on brain structure, brain functions, brain evolution and emotional evolution. Feelings in humans are composed of primitive emotion, basic emotion, social feeling and intellectual feeling, with respect to evolution. Primitive emotion is composed of pleasure and unpleasure, that are affected by body homeostasis in relation to environment. Basic emotion is composed of joy, anger, fear, disgust and acceptance or love, that are strongly dependent on survival of predator-prey situations, and gene competition for sexual selection. Social feeling might be induced by cooperation and competition in groups. Intellectual feeling is separated from social feeling in humans, and functions on a symbiotic and existence nature. This paper discusses each nature on four levels of human feeling based on hierarchical hypothesis of feelings.