Facial electromyography
Encyclopedia
Facial Electromyography (fEMG) refers to an electromyography
(EMG) technique that measures muscle activity by detecting and amplifying the tiny electrical impulses that are generated by muscle fibers when they contract.
It primarily focuses on two major muscle groups in the face, the corrugator supercilli
and zygomaticus major muscle
groups.
al reaction. Studies have found that activity of the corrugator muscle, which lowers the eyebrow and is involved in producing frowns, varies inversely with the emotional valence of presented stimuli
and reports of mood
state. Activity of the zygomatic muscle, which controls smiling, is said to be positively associated with positive emotional stimuli and positive mood state.
Facial EMG has been used as a technique to distinguish and track positive and negative emotional reactions to a stimulus as they occur. A large number of those experiments have been conducted in controlled laboratory environments using a range of stimuli, e.g., still pictures, movie clips and music pieces.
It has also been used to investigate emotional responses in individuals with autism
spectrum disorders.
and in Gaming.
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
(EMG) technique that measures muscle activity by detecting and amplifying the tiny electrical impulses that are generated by muscle fibers when they contract.
It primarily focuses on two major muscle groups in the face, the corrugator supercilli
Corrugator supercilii muscle
The Corrugator supercilii is a small, narrow, pyramidal muscle, placed at the medial end of the eyebrow, beneath the Frontalis and just above Orbicularis oculi....
and zygomaticus major muscle
Zygomaticus major muscle
The Zygomatic major is a muscle of the human body. It is a muscle of facial expression which draws the angle of the mouth superiorly and posteriorly . Like all muscles of facial expression, the zygomatic major is innervated by the facial nerve...
groups.
Uses
Facial EMG has been studied to assess its utility as a tool for measuring emotionEmotion
Emotion is a complex psychophysiological experience of an individual's state of mind as interacting with biochemical and environmental influences. In humans, emotion fundamentally involves "physiological arousal, expressive behaviors, and conscious experience." Emotion is associated with mood,...
al reaction. Studies have found that activity of the corrugator muscle, which lowers the eyebrow and is involved in producing frowns, varies inversely with the emotional valence of presented stimuli
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....
and reports of mood
Mood (psychology)
A mood is a relatively long lasting emotional state. Moods differ from emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event....
state. Activity of the zygomatic muscle, which controls smiling, is said to be positively associated with positive emotional stimuli and positive mood state.
Facial EMG has been used as a technique to distinguish and track positive and negative emotional reactions to a stimulus as they occur. A large number of those experiments have been conducted in controlled laboratory environments using a range of stimuli, e.g., still pictures, movie clips and music pieces.
It has also been used to investigate emotional responses in individuals with autism
Autism
Autism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old. Autism affects information processing in the brain by altering how nerve cells and their...
spectrum disorders.
Facial EMG and Market Research
Two areas where facial EMG techniques have been used are in Advertising ResearchAdvertising research
Advertising research is a specialized form of marketing research conducted to improve the efficiency of advertising. According to MarketConscious.com, “It may focus on a specific ad or campaign, or may be directed at a more general understanding of how advertising works or how consumers use the...
and in Gaming.
- Advertising Research - Of late, facial EMG has been used to test audience response to commercial advertising. Facial EMG activity measures during a viewing of commercials embedded in TV program clips have been used to describe a commercial's level of emotional activation and engagement. Measurement of the corrugator and zygomatic muscles, yield an overall positive and negative emotional activation score. The moment to moment activation that are recorded are said to measure the dynamic emotional response to a commercial and yield useful insights about the elements of the commercials.
- Gaming and Human-Computer Interaction (HCI) - Ravaja, Hazlett and Mandryk used facial EMG techniques to demonstrate that positive and negative emotions can be measured in real time during video game play. The emotional profiling of games give a useful evaluation of a game's impact on a player, how compelling they find the game, how the game measures up to other games in its genre, and how the different elements of the game enhance or detract from the game's approach to engaging the player.
Advantages
Proponents of Facial EMG point to the following advantages:- Facial Electromyography (or fEMG) is a precise and sensitive method to measure emotional expression.
- Unlike self-reports, fEMG does not depend upon language and does not require cognitive effort or memory.
- fEMG is capable of registering the response even when subjects were instructed to inhibit their emotional expression.
- Yields a lot of data and is continuous and scalar (hence more credible.)
- It is able to measure facial muscle activities to even weakly evocative emotional stimuli.
- Less intrusive than other physiological measures like fMRI and EEGEEGEEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
. - Like other physiological measures, facial EMG measurement technique is often the only useful approach when movement is not visible.
Criticisms
- The technique is intrusive and may alter natural expression.
- Number of muscles it can work with is limited by how many electrodes can be attached to face.
- Certain medicines that act on the nervous system (such as muscle relaxants and anticholinergicAnticholinergicAn anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. An example of an anticholinergic is dicycloverine, and the classic example is atropine....
s) can change electromyography (EMG) results. - Quantity of validity work with facial EMG is much less.