1. A method for causing a virtual character to demonstrate awareness of a user's position or activity, the method comprising, detecting the user's position by detecting the position of a portable device, the portable device being substantially colocational with the user, the position and movement of the portable device being controlled by the user, the portable device including a camera and a display; capturing a first image stream of a real-world scene at the camera; generating a second image stream based on the first image stream, the second image stream comprising an augmented reality scene formed by inserting a virtual character into the real-world scene as captured in the first image stream, the virtual character configured to perform an action indicating awareness of the position or activity of the user; displaying the second image stream on the display of the portable device.