Micro-expressions in non-verbal communication is a different name for a facial expression (mimicry). They are spontanous (purpously, involuntarily) movements on a human face which cause contractions of the facial muscles. The basic caracteristic of those movements is that they are caused by emotions which people feel in one particular moment and they last for less than a half of second.
Micro-expressions were discovered in the 60’s by Haggard and Isaack. In this study from 1966. they said that they have discovered this ”micro-moments” of expressions during ”watching video tapes of psychotheraputic sessions, while looking for signs of non-verbal communication between a therapist and a patient”.
Ekman and Friesen have broke the ice in research of facial expressions and proved that there are seven basic emotions, which are universal for all nations and cultures around the world. It’s interesting that Charles Darwin was the first one who wrote about micro-expressions in his book ”The Expression of the Emotions in Man and Animals” all the way back in 1872. Paul Ekman was the one who took Darwin’s work to the next level. In his study about emotions and their connection with facial expressions, he proved that micro-expressions are not defined by culture but given by nature and universal for all the cultures in the world. Ekman participated in developing Facial Action Coding System – FACS, in 1976. together with Wallace V. Friesen. FACS is a system which taxonomizes facial expressions and it’s used even today by psychologists, researchers an animators.