Facial Action Coding System (FACS) is a system originally developed by Paul Ekman and Wallace Friesen in 1976, to taxonomize every conceivable human facial expression. It is the most popular standard currently used to systematically categorize the physical expression of emotions, and it has proven useful both to psychologists and to animators. Paul Ekman (born 1934) was born in Washington, DC and grew up in Newark, New Jersey, Washington, Oregon, and southern California. ... Photographs from the 1862 book Mécanisme de la Physionomie Humaine by Guillaume Duchenne. ... A psychologist is a scientist who studies psychology, the systematic investigation of the human behavior and mental processes. ... An animator is one who is involved in the process of animation. ...

It defines expressions as one of 46 "Action Units", which is a contraction or relaxation of one or more muscles. For example, it can be used to distinguish the two types of smiles as follows: An Iraqi girl smiles In physiology, a smile is a facial expression formed by flexing muscles most notably near both ends of the mouth, but also around the eyes. ...

• 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, and pars orbitalis

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. [1] The Zygomatic major is a muscle of the human body. ... The Zygomatic major is a muscle of the human body. ... The Orbicularis oculi is a muscle of the human body. ... The orbital or horizontal part of the frontal bone (pars orbitalis) consists of two thin triangular plates, the orbital plates, which form the vaults of the orbits, and are separated from one another by a median gap, the ethmoidal notch. ...

Computer graphical face models, such as CANDIDE or Artnatomy, allow expressions to be artificially posed by setting the desired action units.

Codes for common action units

(Also see the list of facial muscles.) This is a list of muscles of the human anatomy. ...

Action units involving facial muscles

• 1 Inner Brow Raiser -- Frontalis (pars medialis)
• 2 Outer Brow Raiser -- Frontalis (pars lateralis)
• 4 Brow Lowerer -- Corrugator supercilii, Depressor 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 alaquae nasi
• 10 Upper Lip Raiser -- Levator labii superioris
• 11 Nasolabial Deepener -- Zygomaticus minor
• 12 Lip Corner Puller -- Zygomaticus major
• 13 Cheek Puffer -- Levator anguli oris (a.k.a. Caninus)
• 14 Dimpler -- Buccinator
• 15 Lip Corner Depressor -- Depressor anguli oris (a.k.a. Triangularis)
• 16 Lower Lip Depressor -- Depressor labii inferioris
• 17 Chin Raiser -- Mentalis
• 18 Lip Puckerer -- Incisivii labii superioris and Incisivii labii inferioris
• 19 Tongue Show
• 20 Lip stretcher -- Risorius w/ platysma
• 21 Neck Tightener
• 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 Bite
• 33 Blow
• 34 Puff
• 35 Suck
• 36 Bulge
• 37 Lip Wipe
• 38 Nostril Dilator
• 39 Nostril Compressor
• 41 Lid droop -- Relaxation of Levator palpebrae superioris
• 42 Slit -- Orbicularis oculi
• 43 Eyes Closed -- Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)
• 44 Squint -- Orbicularis oculi (pars palpebralis)
• 45 Blink -- Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)
• 46 Wink -- Relaxation of Levator palpebrae superioris; Orbicularis oculi (pars palpebralis)

The Frontalis is a muscle of the human body. ... In human and zoological anatomy (sometimes called zootomy), several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The Frontalis is a muscle of the human body. ... In human and zoological anatomy (sometimes called zootomy), several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The Corrugator supercilii is a small, narrow, pyramidal muscle, placed at the medial end of the eyebrow, beneath the Frontalis and Orbicularis oculi. ... The Depressor supercilii is an eye muscle of the human body. ... The levator palpebrae superioris muscle is a muscle in the orbit that elevates the superior (upper) eyelid. ... The Orbicularis oculi is a muscle of the human body. ... The orbital or horizontal part of the frontal bone (pars orbitalis) consists of two thin triangular plates, the orbital plates, which form the vaults of the orbits, and are separated from one another by a median gap, the ethmoidal notch. ... The Orbicularis oculi is a muscle of the human body. ... Pars palpebralis in a medical context means relating to the eyelids. ... The Levator labii superioris alaeque nasi muscle is, translated from Latin, the lifter of the upper lip and of the wing of the nose. It is the muscle with the longest name in the human body. ... The Levator labii superioris is a muscle of the human body used in facial expression. ... The Zygomaticus minor is a muscle of the human body. ... The Zygomatic major is a muscle of the human body. ... The Levator anguli oris is a muscle of the human body. ... The Caninus (Levator anguli oris) arises from the canine fossa, immediately below the infraorbital foramen; its fibers are inserted into the angle of the mouth, intermingling with those of the Zygomaticus, Triangularis, and Orbicularis oris. ... Buccinator The buccinator is a muscle of which the bulk of is located in the cheeks. ... The Depressor anguli oris is a muscle of the human body. ... The Triangularis (Depressor anguli oris) arises from the oblique line of the mandible, whence its fibers converge, to be inserted, by a narrow fasciculus, into the angle of the mouth. ... The Depressor labii is part of a small quadrilateral muscle. ... The Mentalis is a muscle of the human body. ... In human anatomy, the orbicularis oris muscle is the sphincter muscle around the mouth. ... In human anatomy, the orbicularis oris muscle is the sphincter muscle around the mouth. ... The Risorius is a muscle of the human body. ... The platysma is a superficial muscle that stretches from the clavicle to the mandible overlapping the sternocleidomastoid. ... The orbicularis oris is the sphincter muscle around the mouth. ... The orbicularis oris is the sphincter muscle around the mouth. ... The orbicularis oris is the sphincter muscle around the mouth. ... The Depressor labii is part of a small quadrilateral muscle. ... The Mentalis is a muscle of the human body. ... The orbicularis oris is the sphincter muscle around the mouth. ... In human anatomy, the masseter is one of the muscles of mastication. ... The temporalis muscle is one of the muscles of mastication. ... The medial pterygoid, or Pterygoideus internus (Internal pterygoid muscle), is a muscle of mastication with two heads. ... Pterygoid (from the Greek for winglike) can refer to: a plate near the Vomer bone a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle a branch of the Mandibular nerve This is a disambiguation page: a list of articles associated with the same title. ... The Digastric is a muscle of the human body. ... The orbicularis oris is the sphincter muscle around the mouth. ... The levator palpebrae superioris muscle is a muscle in the orbit that elevates the superior (upper) eyelid. ... The Orbicularis oculi is a muscle of the human body. ... The levator palpebrae superioris muscle is a muscle in the orbit that elevates the superior (upper) eyelid. ... The Orbicularis oculi is a muscle of the human body. ... Pars palpebralis in a medical context means relating to the eyelids. ... The Orbicularis oculi is a muscle of the human body. ... Pars palpebralis in a medical context means relating to the eyelids. ... The levator palpebrae superioris muscle is a muscle in the orbit that elevates the superior (upper) eyelid. ... The Orbicularis oculi is a muscle of the human body. ... Pars palpebralis in a medical context means relating to the eyelids. ... The levator palpebrae superioris muscle is a muscle in the orbit that elevates the superior (upper) eyelid. ... The Orbicularis oculi is a muscle of the human body. ... Pars palpebralis in a medical context means relating to the eyelids. ...

Other action units

• 51 Head turn left
• 52 Head turn right
• 53 Head up
• 54 Head down
• 55 Head tilt left
• 56 Head tilt right
• 57 Head forward
• 58 Head back
• 61 Eyes turn left
• 62 Eyes turn right
• 63 Eyes up
• 64 Eyes down
• 65 Walleye
• 66 Cross-eye

See also

• Microexpression

A microexpression is a tiny facial expression that lasts less than a quarter of a second. ...

External links

• Flash demo of facial muscles and their emotions
• New Yorker article discussing FACS
• Details from 1978 edition of FACS
• overview
• Site at WPI
• Article at About.com