Psychologist and researcher, Robert Plutchik created The wheel of Emotions – a model of human emotions and their relations and combinations. It consists of 8 basic emotions, opposed in pairs, and multiple shades.
The model resulted in a circumplex where emotions and variations are represented by different colors and hues. This circumplex can be flattened in a 2D view (see below) to allow viewing of all emotions at once.
Plutchik identified eight primary emotions, which he coordinated in pairs of opposites: joy versus sadness; trust versus disgust; fear versus anger and anticipation versus surprise.
Intensity of emotion and indicator color increases toward the center of the wheel and decreases outward. Akin to a color wheel, variations in color intensity correspond to variations in emotional intensity. Thus, the eight primary emotions occupy the middle ring of the flower with more intense forms occurring in the center (depicted by bolder colors) and milder forms the extremities (depicted by paler colors).
For example, “Rage” is the stronger form of “Anger” while “Annoyance” is the weaker. Similarly, terror becomes fear and then apprehension; Ecstasy becomes joy and then serenity.
Further, secondary emotions are displayed as combinations of the primary ones: Acceptance and apprehension combine to create submission.
Personally, I find this model pretty illuminating. Although, Plutcih’s model is a good start, it seems to be incomplete. It has often been argued that many complex emotions have not found place in this model. To that extent, this model is limited.