Micro expressions are a brief, involuntary facial expression shown on the face of humans according to emotions experienced. They usually occur in high-stakes situations, where people have something to lose or gain. Micro expressions occur when a person is consciously trying to conceal all signs of how he or she is feeling, or when a person does not consciously know how he or she is feeling.  Unlike regular facial expressions, it is difficult to hide micro expression reactions. Micro expressions express the six universal emotions: disgust, anger, fear, sadness, happiness, and surprise. Nevertheless, in the 1990s, Paul Ekman expanded his list of emotions, including a range of positive and negative emotions not all of which are encoded in facial muscles.

These emotions are amusement, contempt, embarrassment, anxiety, guilt, pride, relief, contentment, pleasure, and shame.  They are very brief in duration, lasting only 1/25 to 1/15 of a second.

Micro Expressions Types

Microexpressions are typically classified based on how an expression is modified. They exist in three groups:

  • Simulated expressions: when a microexpression is not accompanied by a genuine emotion. This is the most commonly studied form of microexpression because of its nature. It occurs when there is a brief flash of an expression, and then returns to a neutral state.
  • Neutralized expressions: when a genuine expression is suppressed and the face remains neutral. This type of micro-expression is not observable due to the successful suppression of it by a person.
  • Masked expressions: when a genuine expression is completely masked by a falsified expression. Masked expressions are microexpressions that are intended to be hidden, either subconsciously or consciously.

Micro Expressions in photographs and films

Microexpressions can be difficult to recognize, but still images and video can make them easier to perceive. In order to learn how to recognize the way that various emotions register across parts of the face, Ekman and Friesen recommend the study of what they call “facial blueprint photographs,” photographic studies of “the same person showing all the emotions” under consistent photographic conditions. However, because of their extremely short duration, by definition, micro expressions can happen too quickly to capture with traditional photography. Both Condon and Gottman compiled their seminal research by intensively reviewing film footage. Frame rate manipulation also allows the viewer to distinguish distinct emotions, as well as their stages and progressions, which would otherwise be too subtle to identify.



This technique is demonstrated in the short film Thought Moments by Michael Simon Toon.   Paul Ekman also has materials he has created on his website that teach people how to identify micro expressions using various photographs, including photos he took during his research period in New Guinea.

Moods vs emotions

Moods differ from emotions in that the feelings involved last over a longer period. For example, a feeling of anger lasting for just a few minutes, or even for an hour, is called an emotion. But if the person remains angry all day, or becomes angry a dozen times during that day, or is angry for days, then it is a mood. Many people describe this as a person being irritable, or that the person is in an angry mood. As Paul Ekman described, it is possible but unlikely for a person in this mood to show a complete anger facial expression. More often just a trace of that angry facial expression may be held over a considerable period-a tightened jaw or tensed lower eyelid, or lip pressed against lip, or brows drawn down and together. Emotions are defined as a complex pattern of changes, including physiological arousal, feelings, cognitive processes, and behavioral reactions, made in response to a situation perceived to be personally significant.

Controlled micro expressions

Facial expressions are not just uncontrolled instances. Some may be in fact voluntary, another involuntary; thus one may be truthful and another false. Facial expression may be controlled or uncontrolled. Some people are born able to control their expressions (such as pathological liars), while others are trained, for example actors. “Natural liars” know about their ability to control micro expressions, and so do those who know them well. They have been getting away with things since childhood, fooling their parents, teachers, and friends when they wanted to. People can simulate emotion expressions, attempting to create the impression that they feel an emotion when they are not experiencing it at all. A person may show an expression that looks like fear when in fact he feels nothing, or feels sadness or some other emotion. Facial expressions of emotion are controlled for various reasons, whether cultural or by social conventions. For example, in the United States many little boys learn the cultural display rule, “little men do not cry or look afraid.” There are also more personal display rules, not learned by most people within a culture, but the product of the idiosyncrasies of a particular family. A child may be taught never to look angrily at his father, or never to show sadness when disappointed. These display rules, whether cultural ones shared by most people or personal, individual ones, are usually so well-learned, and learned so early, that the control of the facial expression they dictate is done automatically without thinking or awareness.

Lies and leakage of micro expressions

There is no sign of deceit itself. There is no gesture, facial expression, nor muscle twitch that in and of itself means that a person is lying. There are only clues that the person is poorly prepared and clues of emotions that don’t fit what the person is saying we call them micro expressions. These are what provide leakage or deception clues. Micro expressions are used as a way to detect if there is something off in a statement that a person mentions. They do not determine a lie but are a form of detecting concealed emotion. Dr. David Matsumoto explains that one must not conclude that someone is lying if a micro expression is detected but that there is more to the story than is being told.

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