Some of Valve's biofeedback tests have included tracking player sweat levels and changing gameplay experiences accordingly, according to the company's experimental psychologist.
VentureBeat attended the NeuroGaming Conference and Expo last week, where Valve's Mike Ambinder discussed the various studies the Half-Life studio is conducting as it looks towards the future of gaming.
"One thing we are very interested in is the notion of biofeedback and how it can be applied to game design,” Ambinder said. "There is potential on both sides of the equation, both for using physiological signals to quantify an emotional state while people are playing the game."
Concerning Valve's player perspiration tests, the company has measured players' sweat and matched that to their level of arousal while playing a certain game. In one case, this data was fed into Left 4 Dead and the gameplay experience was modified to be "more fun."
Ambinder also revealed that Valve conducted an experiment where a player had four minutes to shoot 100 enemies. If the player was calm, the game would advance normally, but if they became nervous, the game would unfold more quickly, leaving less time to kill the enemies.
Valve is also experimenting with eye-tracking, creating a prototype version of Portal 2 that could be manipulated with eye movement. All of the company's studies are purely experimental for the time being and still have a ways to go, Ambinder said.
"The more interesting side of the equation is what you can do when you incorporate physiological signals into the gameplay itself," he said. "If we could start tapping into that, we could tap into a whole wealth of data."