What you see is not what others see. We inhabit parallel worlds of perception, bounded by our interests and experience. What is obvious to some is invisible to others. I might find myself standing, transfixed, by the roadside, watching a sparrowhawk hunting among the bushes, astonished that other people could ignore it. But they might just as well be wondering how I could have failed to notice the new V6 Pentastar Sahara that just drove past.
As the psychologist Richard Wiseman points out: “At any one moment, your eyes and brain only have the processing power to look at a very small part of your surroundings … your brain quickly identifies what it considers to be the most significant aspects of your surroundings, and focuses almost all of its attention on these elements.” Everything else remains unseen.