Aside from trying to understand what exactly emotions are, researchers have also tried to identify and classify the various types of emotions.
Paul Eckman, a psychologist, suggested in 1972 that there are actually six basic emotions that can be considered universal in all human cultures, and they are: anger, fear, disgust, surprise, sadness, and happiness. But in 1999, he further expanded the list, including some other basic emotions such as excitement, embarrassment, contempt, pride, shame, amusement and satisfaction.