Facial Action Coding System

http://blogs.law.harvard.edu/preserving/2012/09/24/face-to-face-physiognomy-phrenology/

Facial Action Coding System (FACS) is a system to taxonomy (process of classification or science of classification) human facial expressions. It is the most widely used and versatile method for measuring and describing facial behaviors. Paul Ekman and W.V. Friesen developed the original FACS in the 1970s by determining how the contraction of each facial muscle (singly and in combination with other muscles) changes the appearance of the face. They examined videotapes of facial behavior to identify the specific changes that occurred with muscular contractions and how best to differentiate one from another. They associated the appearance changes with the action of muscles that produced them by studying anatomy, reproducing the appearances, and palpating their faces. Their goal was to create a reliable means for skilled human scorers to determine the category or categories in which to fit each facial behavior. The FACS Manual was first published in a loose-leaf version with video or film supplements in 1978. It is a common standard to systematically categorize the physical expression of emotions, It has proven useful to psychologists, counselors, government agencies and more. About PAUL EKMAN ( https://face.paulekman.com/face/default.aspx ) For 32 years, Paul Ekman was a Professor of Psychology in the Department of Psychiatry at the University of California at San Francisco. His interests have focused on two separate but related topics. He originally focused on ‘nonverbal’ behavior, and by the mid-60’s concentrated on the expression and physiology of emotion. His second interest is interpersonal deception. He did an interview on "face to face" ( http://globetrotter.berkeley.edu/people4/Ekman/ekman-con0.html )

Another terminology coming in relation with FACS are Action Units (AUs) and Action Descriptors(ADs). To decode almost all possibility of facial muscle movement during expression we need FACS, which deconstructing it into the specific Action Units (AU) and their temporal segments that produced the expression. These FACS measurement units are Action Units (AUs), not muscles, for two reasons. First, for a few appearances, more than one muscle was combined into a single AU because the changes in appearance they produced could not be distinguished. Second, the appearance changes produced by one muscle were sometimes separated into two or more AUs to represent relatively independent actions of different parts of the muscle. (After all, facial muscles were identified and named by anatomists, not behavioral psychologists.) AUs are independent of any interpretation, they can be used for any higher order decision making process including recognition of basic emotions, or pre-programmed commands for an ambient intelligent environment. To know more about this AU and AD, you may look for "Dr. Ekman’s interpretation". He had describe about the expression and its meaning. These are very important to understand the agony of patients, those who are unable to express themselves verbally, or to detect depression and sign of suicidal tendency, or to differentiate criminals and terrorist from a crowd. FACS defines AUs, which are a contraction or relaxation of one or more muscles. It also defines a number of Action Descriptors, which differ from AUs. A FACS coder "dissects" an observed expression, decomposing it into the specific AUs that produced the movement. The scores for a facial expression consist of the list of AUs that produced it. Duration, intensity, and asymmetry can also be recorded.

Action Units (AUs) are the fundamental actions of individual muscles or groups of muscles. Action Descriptors (ADs) are unitary movements that may involve the actions of several muscle groups

in a simple language: FACS can be used to distinguish two types of smiles as follows:

Insincere and voluntary Pan American smile: contraction of zygomatic major alone Sincere and involuntary Duchenne smile: contraction of zygomatic major and inferior part of orbicularis oculi. Although the labeling of expressions currently requires trained experts, researchers have had some success in using computers to automatically identify FACS codes, and thus quickly identify emotions. Computer Graphical (CG) face models, such as CANDIDE or Artnatomy, allow expressions to be artificially posed by setting the desired action units.

The Facial Action Coding System (FACS) Manual is a detailed, technical guide that explains how to categorize facial behaviors based on the muscles that produce them, i.e., how muscular action is related to facial appearances. It illustrates appearance changes of the face using written descriptions, still images, and digital video examples. Behavioral scientists, CG animators, computer scientists interested in pattern recognition programs, and other technicians and scientists use FACS in their professional work when they need to know the exact movements that the face can perform, and what muscles produce them. Working through the exercises of the FACS Manual may also enable greater awareness of and sensitivity to subtle facial behaviors that could be useful for psychotherapists, interviewers, and other practitioners who must penetrate deeply into interpersonal communications.

Lateral View of muscle of face

Lateral View of muscle of neck

List of Action Units and Action Descriptors (with underlying facial muscles)

AU Number FACS Name

Muscular Basis

0

Neutral Face

1

Inner Brow Raiser

Frontalis (pars medialis)

2

Outer Brow Raiser

Frontalis (pars lateralis)

4

Brow Lowerer

Depressor glabellae, Depressor supercilii, Corrugator supercilii

5

Upper Lid Raiser

Levator palpebrae superioris

6

Cheek Raiser

Orbicularis oculi (pars orbitalis)

7

Lid Tightener

Orbicularis oculi (pars palpebralis)

9

Nose Wrinkler

Levator labii superioris alaeque nasi

10

Upper Lip Raiser

Levator labii superioris, caput infraorbitalis

11

Nasolabial Deepener

Zygomaticus minor

12

Lip Corner Puller

Zygomaticus major

13

Sharp Lip Puller

Levator anguli oris (also known as Caninus)

14

Dimpler

Buccinator

15

Lip Corner Depressor

Depressor anguli oris (also known as Triangularis)

16

Lower Lip Depressor

Depressor labii inferioris

17

Chin Raiser

Mentalis

18

Lip Pucker

Incisivii labii superioris and Incisivii labii inferioris

19

Tongue Show

20

Lip Stretcher

Risorius w/ platysma

21

Neck Tightener

Platysma

22

Lip Funneler

Orbicularis oris

23

Lip Tightener

Orbicularis oris

24

Lip Pressor

Orbicularis oris

25

Lips Part

Depressor labii inferioris or relaxation of Mentalis, or Orbicularis oris

26

Jaw Drop

Masseter, relaxed Temporalis and internal pterygoid

27

Mouth Stretch

Pterygoids, Digastric

28

Lip Suck

Orbicularis oris

29

Jaw Thrust

30

Jaw Sideways

31

Jaw Clencher

32

[Lip] Bite

33

[Cheek] Blow

34

[Cheek] Puff

35

[Cheek] Suck

36

[Tongue] Bulge

37

Lip Wipe

38

Nostril Dilator

39

Nostril Compressor

41

Glabella Lowerer

42

Inner Eyebrow Lowerer Separate Strand of AU 4

43

Eyes Closed

Masseter

Separate Strand of AU 4

Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)

44

Eyebrow Gatherer

Separate Strand of AU 4

45

Blink

Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)

46

Wink

Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)

Head Movement Code

AU Number

FACS Name

51

Head Turn Left

52

Head Turn Right

53

Head Up

54

Head Down

55

Head Tilt Left

M55

Head Tilt Left

56

Head Tilt Right

M56

Head Tilt Right

57

Head Forward

M57

Head Thrust Forward

58

Head Back

M59

Head Shake Up and Down

The onset of 17+24 is immediately preceded, accompanied, or followed an up-down head shake (nod).

M60

Head Shake Side to Side

The onset of 17+24 is immediately preceded, accompanied, or followed by a side to side head shake.

M83

Head Upward and to the Side

The onset of the symmetrical 14 is immediately preceded or accompanied by a movement of the head, upward and turned and/or tilted to either the left or right.

Action

The onset of the symmetrical 14 is immediately preceded or accompanied by a head tilt to the left.

The onset of the symmetrical 14 is immediately preceded or accompanied by a head tilt to the right.

The onset of 17+24 is immediately preceded, accompanied, or followed by a head thrust forward.

Eye Movement Codes AU FACS Name Number

Action

61

Eyes Turn Left

M61

Eyes Left

62

Eyes Turn Right

M62

Eyes Right

63

Eyes Up

65

Eyes Down

65

Walleye

66

Cross-eye

M68

Upward Rolling of Eyes

The onset of the symmetrical 14 is immediately preceded or accompanied by an upward rolling of the eyes.

69

Eyes Positioned to Look at Other Person

The 4, 5, or 7, alone or in combination, occurs while the eye position is fixed on the other person in the conversation.

M69

Head and/or Eyes Look at Other Person

The onset of the symmetrical 14 or AUs 4, 5, and 7, alone or in combination, is immediately preceded or accompanied by a movement of the eyes or of the head and eyes to look at the other person in the conversation.

Visibility Codes

The onset of the symmetrical 14 is immediately preceded or accompanied by eye movement to the left.

The onset of the symmetrical 14 is immediately preceded or accompanied by eye movement to the right.

AU Number FACS Name 70

Brows and forehead not visible

71

Eyes not visible

72

Lower face not visible

73

Entire face not visible

74

Unscorable

Gross Behavior Codes These codes are reserved for recording information about gross behaviors that may be relevant to the facial actions that are scored. AU Number FACS Name 40

Sniff

50

Speech

80

Swallow

81

Chewing

82

Shoulder shrug

84

Head shake back and forth

85

Head nod up and down

91

Flash

92

Partial flash

97

Shiver/Tremble

98

Fast up-down look

Facial expressions

Some common examples of feelings that can be expressed by characters are:

Some more basic expressions of emotions are: Concentration Confusion Desire Excitement Empathy Flirt Frustration Glare Gross Snarl, mainly involving the levator labii superioris alaeque nasi muscle

The muscles of facial expression for human (Homo sapiens) Auricularis anterior muscle Buccinator muscle Corrugator supercilii muscle Depressor anguli oris muscle Depressor labii inferioris muscle Depressor septi nasi muscle Frontalis muscle Levator anguli oris muscle Levator labii superioris alaeque nasi muscle Levator labii superioris muscle Mentalis muscle

Modiolus muscle Nasalis muscle Orbicularis oculi muscle Orbicularis oris muscle Platysma muscle Procerus muscle Risorius muscle Zygomaticus major muscle Zygomaticus minor muscle