Are you pretty sharp? Do you pride yourself on your Holmes-like powers of observation? Try watching 'Bet You Can't Do This' (make sure you've got the sound on your computer turned on).

Discuss this video, and watch other thought-provoking films on the OU YouTube channel.

The explanation

You might be wondering how we hid a mouse in the video. The ruse was powered by something called inattentional blindness.

Inattentional blindness (also called perceptual blindness) is really just the academic term for something magicians rely on everyday – misdirection. But it’s of real interest to psychologists – in fact our clip is based on an original experiment carried out by Daniel Simons of the University of Illinois and another by Christopher Chabris of Harvard University. The question they were interested in trying to explore is just how much of what we see (or don’t see) is a result of our attention.

Small things can make a difference… so you might see that everyone is wearing clothes that are similar in colour to the mouse. Also we added a few red items to the scene to ensure the mouse’s belt didn’t stick out too much.

There are really important consequences to this sort of research. For example, psychologists play a key role in the design of things like road signs – just how do you ensure that drivers concentrating (hopefully) on the road will see things?

What could you do next?

• Check out other examples of inattentional blindness – for example play the Driving Challenge, or watch Zanthor's Coin Magic Trick
• Explore psychology courses at the Open University
• What’s the most surprising thing you can hide in a scene? Post a video response on the 'Bet You Can't Do This' YouTube page

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