Human Computer interface
HCI is lots of different thing e.g. key bored, moues, joysticks, voices commands, wheel, pedals and controllers they are used to input information of what we what to do in the game e.g. jump, re lode, aim down a site switch weapons melee pus the game select something and because of this we need more buttons on the controllers so we need new was to do all of theses thing in the games.