“This discussion of visual perception is part of an introduction to media theory. The prime concern here is with how mediated our experience of the world is. The study of visual perception offers considerable evidence that the world or the image is not ‘given’, as people sometimes say, but constructed. In visual perception we are not like passive cameras, and even the idea that the mind takes selective ‘snapshots’ underplays our active interpretation of the world. These notes focus on key factors which contribute to shaping what we see.” Note: Lecture notes for an Introduction to Media Theory class at the University of Wales.