A system determines which user of multiple users provided input through a single input device. A mechanism captures images of the one or more users. When input is detected, the images may be processed to determine which user provided an input using the input device. The images may be processed to identify each users head and eyes, and determine the focus point for each user's eyes. The user which has eyes focused at the input location is identified as providing the input. When the input mechanism is a touch screen, the user having eyes focused on the touch screen portion which was touched is identified as the source of the input.