Facial Action Coding System

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.

People can learn the technique from a number of sources including manuals and workshops,[7] and obtain certification through testing.

[8] Although the labeling of expressions currently requires trained experts, researchers have had some success in using computers to automatically identify the FACS codes.

[12] The original FACS has been modified to analyze facial movements in several non-human primates, namely chimpanzees,[13] rhesus macaques,[14] gibbons and siamangs,[15] and orangutans.

A study conducted by Vick and others (2006) suggests that the FACS can be modified by taking differences in underlying morphology into account.

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.

[27] For clarification, the FACS is an index of facial expressions, but does not actually provide any bio-mechanical information about the degree of muscle activation.