It seems that Valve tries to experiment with a wide variety of approaches to gaming. We have already heard about the full time economist at Valve, and now we hear more from Mike Ambider – a psychologist working there. During the Neurogaming 2013 Conference and Expo, he has mentioned some experiments making the games react to the players' psychological state.

Left4Dead series Director AI changes the flow of the game depending on players' actions. Internal experiments tried to modify games more, by measuring the sweat of players' hands and evaluating their emotional state based on that. One of the interesting scenarios was the time limited objective of shooting zombies, which run faster when the players were more nervous. Having means to evaluate the fear of the player would allow improving horror games a lot.

Another experiment involved using eye-tracking in Portal. Ambinder said that there is a version of Portal 2 controlled by eye movements that works quite well. He also has mentioned that controlling viewpoint separately from aiming provides a very good experience.

Other indicators of players states were mentioned: heart rate, facial expression, brain waves, pupil dilation, body temperature and more. With this feedback a lot may be possible, especially in measuring the enjoyment of the game. It will be very interesting to see what these experiments will eventually bring to mainstream gaming.