Seeing and space

• Why can the same picture look different?

  What you see depends on what surrounds a thing. The same grey can look like two different greys when the background changes.

• Why do we miss things in a busy scene?

  Noticing a change takes attention. Even a big one can slip past when nothing points you to it.

• How do you picture a place from another viewpoint?

  Experiments suggest two tricks: people imagine moving to another spot to judge left and right, and trace a line of sight to judge what someone sees.

• How do you turn and fold shapes in your head?

  In one classic study, turning a shape in your head took longer the further it was turned. A fold depends on the order the paper’s layers end up in.

These pages explore the ideas behind the puzzles. They don’t interpret your levels, your answers or anyone’s health. How to read your results · Sources