microexpression

thumb|Microexpressions of emotions (in order: surprise, fear/shock, sadness, anger, happiness and disgust)

A microexpression is a facial expression with very short duration. It is the innate result of a voluntary and an involuntary emotional response occurring simultaneously and conflicting with one another. It occurs when the amygdala responds appropriately to the stimuli that the individual experiences and wishes to conceal this specific emotion. This results in briefly displaying their true emotions followed by a false emotional reaction.