Are you observant?

Change blindness demonstrates how we miss big changes in our environment, because our brains can only take in and process a certain amount of information.

How it works

Watch a video of Professor Richard Wiseman performing a card trick, where the cards change colour. At the end of the video, Professor Wiseman explains what you probably missed seeing.

Things to try or ask around the exhibit

Did you notice any changes during the video?


Our eyes and our brains can only handle so much information, so we need to be selective about what we pay attention to. Our brains compensate for any information gaps by ‘editing’ together our impressions, rather than taking an exact ‘recording’.

Richard Wiseman’s video shows how your eyes and brain don’t (and can’t) see or analyse the world in perfect detail. Viewers can be so absorbed in trying to detect when the cards change colour that they usually don’t notice other changes, due to a phenomenon called 'change blindness'. Researchers have also tracked viewers’ eyes while they watched the video, to show how people (mostly) miss the real changes that were occurring before their eyes.

Finding the science in your world

Simple games like ‘spot the difference’ and magic tricks take advantage of our change blindness. In more serious ways, change blindness can influence witness statements about a crime.

Magicians use ‘covert misdirection’ like change blindness to draw suspicion away from what they’re doing and what’s changing.The change may be expected or unexpected, but if your view of the scene is interrupted (by a fleeting blink or saccade of your eyes, screen flicker or the camera changing its angle), you are less able to compare the post-change state with the pre-change state and notice any differences.