FIGURE 1.

Basic emotion and circumplex. (A) Schlosberg proposed two-dimension of facial expression in a roughly circular surface, whose axes are pleasantness–unpleasantness and attention–rejection. The four basic emotions have different levels of activation, for example, fear and anger can reach higher levels of activation. (B) Circumplex model of emotion proposed that all emotions locate specially on a circle of the circumplex, means that different emotions have different arousal or hedonic parameters. Two core affects of emotions, which are represented on the horizontal dimension and vertical dimension, are induced by two features of a stimulus: the safety value of the stimulus and the hedonic value of the stimulus.