In 1970 Paul Ekman described six universal or basic emotions. He did a lot of research. People told him what emotion they thought was displayed in a picture.
Happy, Sad, Angry, Surprised, Scared, and Disgusted, as well as Neutral (no emotion) are the universal emotions he described. In more recent years, other emotions were researched by others to add to these 6 basic emotions. Think about contempt or an affective state like boredom.
The first time these six universal or basic emotions were described was in the magazine California Mental Health Research Digest. It was stated that they are cross cultural.
Each facial expression can be identified by universally produced facial muscle movements. You can use your facial muscles to communicate.
Culturally linked emotional expressions also exist, such as winking or raising one eyebrow.
In addition, the triggers for the display of emotion are sometimes linked to cultural factors. For example in Western cultures emotions are shown more openly compared to Eastern cultures.
The Noldus FaceReader software is able to detect these emotions from live feeds, video files and images.