Valve has been looking at the use of biometrics in games for quite a while now, and they even have an experimental psychologist on staff in the form of Mike Ambinder. He was present at the NeuroGaming Conference and Expo last week to talk about what exactly Valve is trying to achieve with biofeedback, and how it involves gamer sweat and eye movement.The issue Valve sees at the moment with games is that they can’t detect a player’s emotional state. If they could, then the gameplay could react to enhance the experience and potentially make it more enjoyable. So Valve started experimenting with biofeedback, more specifically, they’ve been detecting the pH level of a player’s sweat through skin conductance in order to figure out how calm or nervous they are during play.That information has been fed into a build of Left4Dead where a mission asks the player to kill 100 enemies in 4 minutes. Monitoring the ph level in the sweat sees the game react to someone who is nervous by speeding up gameplay. Players who remain calm have the gameplay speed remain normal.In a similar vein Portal 2 has been patched to allow for control using the player’s eye movement, allowing them to aim with their eyes instead of with their hands. The end result works surprisingly well, but must surely take a bit of getting used to.The experiment is set to continue as well as being expanded to other types of feedback such as heart rate, overall body temperature, and even the expression on your face. It isn’t limited to just impacting gameplay, either. Such biofeedback could be used to better match players for multiplayer games.