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. Lou et al. showed that facial EMG activity can be used to forecast how game players would be addicted to an online game before the game is officially introduced to the market. 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 EEG. 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. The number of muscles it can employ is limited by how many electrodes can be attached to the face. Certain medicines that act on the nervous system, such as muscle relaxants and anticholinergics, can change electromyography (EMG) results. See also Facial Action Coding System Computer processing of body language References Electrophysiology Neurophysiology Neurotechnology Electrodiagnosis Face