Editing Affective computing (section)

====Facial electromyography====
{{Main|Facial electromyography}}

Facial electromyography is a technique used to measure the electrical activity of the facial muscles by amplifying the tiny electrical impulses that are generated by muscle fibers when they contract.<ref name="Larsen JT 2003">Larsen JT, Norris CJ, Cacioppo JT, "[https://web.archive.org/web/20181030170423/https://pdfs.semanticscholar.org/c3a5/4bfbaaade376aee951fe8578e6436be59861.pdf Effects of positive and negative affect on electromyographic activity over zygomaticus major and corrugator supercilii]", (September 2003)</ref>
The face expresses a great deal of emotion, however, there are two main facial muscle groups that are usually studied to detect emotion:
The corrugator supercilii muscle, also known as the 'frowning' muscle, draws the brow down into a frown, and therefore is the best test for negative, unpleasant emotional response.↵The zygomaticus major muscle is responsible for pulling the corners of the mouth back when you smile, and therefore is the muscle used to test for a positive emotional response.

[[File:Gsrplot.svg|500px|thumb|Here we can see a plot of skin resistance measured using GSR and time whilst the subject played a video game. There are several peaks that are clear in the graph, which suggests that GSR is a good method of differentiating between an aroused and a non-aroused state. For example, at the start of the game where there is usually not much exciting game play, there is a high level of resistance recorded, which suggests a low level of conductivity and therefore less arousal. This is in clear contrast with the sudden trough where the player is killed as one is usually very stressed and tense as their character is killed in the game.]]