Console makers are constantly trying not only to innovate, but differentiate themselves from one another, since often times games appear on all platforms at once. For the past few generations it was mostly about graphical improvements, though we've also seen connectivity play a part as well as controller type; with Nintendo's Wii outselling the PS3 and Xbox 360 in the initial stages of its life.
Sony is looking to make further in-roads in controller development, by patenting a design that measures biometrics. Certain measurable things include the player's heartbeat, perspiration levels and muscle movements.
The patent design diagrams show a traditional dual-shock controller having these detectors implemented in its design, as well as newer movement controls. There's also an as-yet-unnamed handheld device that appears to have biometrics involved.
Shacknews has speculated about some of the applications of this device. It could certainly detect your stress levels, or perhaps see if you're lying. There's also the chance of basing your in-game character's mood on some of these stats, maybe haing weaponry hold more steady if the player is more relaxed.
The problem with that is that in almost all games, we're playing a character other than ourselves - someone who can do things we can't. I don't want my in-game character to be as sweaty as I get. My grizzled space marine is suppoed to be cool, damnit - not some sweaty nerd who gets scared of the monsters in minecraft!