ExtremeTech: ''Video games, like most other creative endeavors, require a large investment in time and money. To increase the odds of recouping costs and making a profit, game developers often use focus groups to see if the game is going in the right direction.
Traditionally, that involves watching uninitiated people play the game with limited contextual information. Then, a series of questions are asked to gauge what the players liked and disliked. Now, Taiwanese researchers at the Academia Sinica and National Taiwan University are using electromyography (EMG) to track small muscle movements in the faces of the focus group members. From there, they can estimate how much fun, and how addictive, the gameplay is.''