Muscles of head and neck.

Facial Action Coding System (FACS) is a system to taxonomize human facial movements by their appearance on the face, based on a system originally developed by a Swedish anatomist named Carl-Herman Hjortsjö.^[1] It was later adopted by Paul Ekman and Wallace V. Friesen, and published in 1978.^[2] Ekman, Friesen, and Joseph C. Hager published a significant update to FACS in 2002.^[3] Movements of individual facial muscles are encoded by FACS from slight different instant changes in facial appearance.^[4] It is a common standard to systematically categorize the physical expression of emotions, and it has proven useful to psychologists and to animators. Due to subjectivity and time consumption issues, FACS has been established as a computed automated system that detects faces in videos, extracts the geometrical features of the faces, and then produces temporal profiles of each facial movement.^[4]

Observer-Based Measurement of Facial Expression With the Facial Action Coding System Jeffrey F. Cohn Zara Ambadar Paul Ekman 203 Facial expression has been a focus of emotion research for over a hundred years (Darwin, 1872/1998). It is central to several leading theories of emotion (Ekman.
Jul 05, 2021 The Facial Action Coding System (FACS) is a comprehensive, anatomically based system for describing all visually discernible facial movement. It breaks down facial expressions into individual components of muscle movement, called Action Units (AUs).

It was later adopted by Paul Ekman and Wallace V. Friesen, and published in.Paul Ekman born February 15, 1934 is an American psychologist who is a. Facial Action Coding System FACS to taxonomize every human facial expression. Facs Paul Ekman PDF - Free download as PDF File (.pdf), Text File (.txt) or read online for free. Emotion, we coded the facial expressions, again using Ekman and Friesens Facial Action Coding System, that young boys displayed while taking a brief interactive IQ test (Keltner, Moﬃtt, & Stouthamer-Loeber, 1995). We then related these mea-sures of facial expression to teacher ratings of the boys levels of externalizing disor.

Uses[edit]

Using FACS ^[5] human coders can manually code nearly any anatomically possible facial expression, deconstructing it into the specific action units (AU) and their temporal segments that produced the expression. As 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. The FACS Manual is over 500 pages in length and provides the AUs, as well as Ekman's interpretation of their meaning.

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 in that the authors of FACS have not specified the muscular basis for the action and have not distinguished specific behaviors as precisely as they have for the AUs.

For example, FACS can be used to distinguish two types of smiles as follows:^[6]

Insincere and voluntary Pan-Am 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.^[7]Computer graphical face models, such as CANDIDE or Artnatomy, allow expressions to be artificially posed by setting the desired action units.

The use of FACS has been proposed for use in the analysis of depression,^[8] and the measurement of pain in patients unable to express themselves verbally.^[9]

FACS is designed to be self-instructional. People can learn the technique from a number of sources including manuals and workshops,^[10] and obtain certification through testing.^[11] The original FACS has been modified to analyze facial movements in several non-human primates, namely chimpanzees,^[12] rhesus macaques,^[13] gibbons and siamangs,^[14] and orangutans.^[15] More recently, it was developed also for domestic species, including the dog,^[16] the horse^[17] and the cat.^[18] Similarly to the human FACS, the animal FACS have manuals available online for each species with the respective certification tests.^[19]

Thus, FACS can be used to compare facial repertoires across species due to its anatomical basis. A study conducted by Vick and others (2006) suggests that FACS can be modified by taking differences in underlying morphology into account. Such considerations enable a comparison of the homologous facial movements present in humans and chimpanzees, to show that the facial expressions of both species result from extremely notable appearance changes. The development of FACS tools for different species allows the objective and anatomical study of facial expressions in communicative and emotional contexts. Furthermore, a cross-species analysis of facial expressions can help to answer interesting questions, such as which emotions are uniquely human.^[20]

EMFACS (Emotional Facial Action Coding System)^[21] and FACSAID (Facial Action Coding System Affect Interpretation Dictionary)^[22] consider only emotion-related facial actions. Examples of these are:

Emotion	Action units
Happiness	6+12
Sadness	1+4+15
Surprise	1+2+5B+26
Fear	1+2+4+5+7+20+26
Anger	4+5+7+23
Disgust	9+15+17
Contempt	R12A+R14A

Codes for action units[edit]

For clarification, FACS is an index of facial expressions, but does not actually provide any bio-mechanical information about the degree of muscle activation. Though muscle activation is not part of FACS, the main muscles involved in the facial expression have been added here for the benefit of the reader.

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 (e.g., a forward‐thrusting movement of the jaw). Vorpx crack torrent. The muscular basis for these actions hasn't been specified and specific behaviors haven't been distinguished as precisely as for the AUs.

For most accurate annotation, FACS suggests agreement from at least two independent certified FACS encoders.

Intensity scoring[edit]

Intensities of FACS are annotated by appending letters A–E (for minimal-maximal intensity) to the action unit number (e.g. AU 1A is the weakest trace of AU 1 and AU 1E is the maximum intensity possible for the individual person).

A Trace
B Slight
C Marked or pronounced
D Severe or extreme
E Maximum

Other letter modifiers[edit]

Paul Ekman Facial Action Coding System Pdf

There are other modifiers present in FACS codes for emotional expressions, such as 'R' which represents an action that occurs on the right side of the face and 'L' for actions which occur on the left. An action which is unilateral (occurs on only one side of the face) but has no specific side is indicated with a 'U' and an action which is unilateral but has a stronger side is indicated with an 'A.'

List of action units and action descriptors (with underlying facial muscles)[edit]

Main codes[edit]

AU number	FACS name	Muscular basis
0	Neutral face
1	Inner brow raiser	fr

Paul Ekman Facial Action Coding System Pdf