Robert Plutchik
Robert Plutchik (21 October 1927 – 29 April 2006) was a professor emeritus at the Albert Einstein College of Medicine and adjunct professor at the University of South Florida. He received his Ph.D. from Columbia University and he was also a psychologist. He authored or coauthored more than 260 articles, 45 chapters and eight books and edited seven books. His research interests included the study of emotions, the study of suicide and violence, and the study of the psychotherapy process. Theory of emotion. Plutchik proposed a psychoevolutionary classification approach for general emotional responses. He considered there to be eight  primary emotions—anger, fear, sadness, disgust, surprise, anticipation, trust, and joy. Plutchik argues for the primacy of these emotions by showing each to be the trigger of behaviour with high survival value, such as the way fear inspires the fight-or-flight response. Plutchik's psychoevolutionary theory of basic emotions has ten postulates. Plutchik's wheel of emotions. Plutchik also created a wheel of emotions to illustrate different emotions. Plutchik first proposed his cone-shaped model (3D) or the wheel model (2D) in 1980 to describe how emotions were related. He suggested 8 primary bipolar emotions: joy versus sadness; anger  versus fear; trust versus disgust; and surprise versus anticipation. Additionally, his circumplex model makes connections between the idea of an emotion circle and a color wheel. Like colors, primary emotions can be expressed at different intensities and can mix with one another to form different emotions. The theory was extended to provide the basis for an explanation for psychological defence mechanisms; Plutchik proposed that eight defense mechanisms were manifestations of the eight core emotions. Publications. Plutchik contributed the "Emotions" article to the encyclopedia, "World Book Millennium 2000".