Facial Action Coding System

The 1978 first published Facial Action Coding System (FACS, engl. For, facial movement coding system ') is a worldwide popular among psychologists coding method for describing facial expressions.

History

The first version of the system was developed in 1976 by Paul Ekman and Wallace Friesen. Your main basis was the book Man's Face and Mimic [or Facial ] Language ( The human face and mimic language; Original Title: Människans ansikte och mimiska språket, 1969, Malmo: Studentlitteratur ) of the Swedish anatomist Carl- Herman Hjortsjö of Lund University.

Areas of application

The main application field is the psychology of emotions. With its help you can, for example, a real differ from a contrived smile. FACS is thus a technique for facial expression or emotion recognition.

The sub -control Attach the muscles involved in an expression requires an - albeit short - period. During this time, the underlying feeling is displayed correctly in a complete expression. Thereafter, the expression is replaced by the expression that the person wants to represent. This process is referred to in German as a micro facial expressions.

A recognized FACS coding is required usually by two independent, certified coders. Part of the certification is the ability to produce the individual elements of the system with its own face.

In addition, FACS is increasingly used as a basis for computer animation of facial expressions, such as in films like Beowulf, Benjamin Button and Avatar.

Structure of coding FACS

The FACS assigns virtually any visible movement of the facial muscles to a " mover " (English Action Unit, AU ). These are units that combine a single or multiple muscle movements. With this classification it is possible to facial expressions written record - comparable to the notation of verbal expressions with written language. In FACS, there are a total of 44 such units, the upper face consists of 12, the lower face 32 AUs. The AUs in the lower face are divided as to the direction of movement. Thus, horizontal, vertical, oblique, circular and mixed actions can be distinguished.

Select from the list of axes ( Action Units )

  • 01 Raise the eyebrows inside
  • 02 Raise the eyebrows outside
  • 04 contraction of the eyebrows
  • 05 Lift the upper eyelid
  • 06 contraction of the outer part of the ring muscle around the eyes ( crows feet it is usually caused thereby )
  • 07 contraction of the inner part of the orbicular muscle of the eye ( of the lower tensioning possibly also of the upper eyelid )
  • 09 hulls of the nose
  • 10 raising of the upper lip levator labii superioris by the
  • Pull 11 exterior part of the upper lip obliquely upward
  • 12 lifting the corners of his mouth as when smiling or laughing (see also laugh muscles)
  • 13 lace lifting the corners of the mouth ( " Chaplin Smile," historically referred to as hysterical smile )
  • 14 Einziehn corners of the mouth trumpet - muscle
  • 15 pulling down the corners of the mouth
  • 16 Down Pull the lower lip
  • 17 pushing up the chin
  • 18 Pout
  • Bulge 22 funnel-shaped lips outward
  • 23 margins of the lips, they are narrow, rolled inwards and flattened to the teeth
  • 24 compression of the lips ( orbicularis oris)
  • 25 Open the lips
  • 26 opening the mouth by relaxing the jaw muscles
  • 27 wide opening of the mouth
  • 28 sucking lips between her teeth
  • 43 lowering of the upper eyelid ( 43E = eyes closed)
  • 45 Blink ( with both eyes )
  • 46 Wink ( with one eye )

More action units describe the possible head and eye movements.

Encoding the expression strength

The strength of a movement is expressed by a five-point rank value in FACS. For each AU is specified in the manual explicitly a mapping rule.

Most of the following applies:

  • Level A: on the threshold of perception or implied
  • Strength B: visible
  • Strength C: clearly visible
  • Strength D: pronounced
  • Strength E: in the physiological maximum (individual)

The characteristic strength is not to be confused with the expression, since the effect of an expression does not depend solely on the strength of muscle movement.

EmFACS

The EmFACS stands for Emotion FACS and contains only those motor units that are needed for encoding frequent emotional facial expressions ( happiness, sadness, anger, fear, disgust and surprise). The system was developed by Paul Ekman and WV Friesen in the 1980s at the University of California San Francisco.

ChimpFACS

ChimpFACS is a development for the analysis of facial expression of chimpanzees. It allows a direct structural comparison of facial expressions by chimpanzees and humans.

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