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READ INSTRUCTIONS BEFORE STARTING VIDEO: Once you start the video you will be presented with a series of words, printed in different colours. We aren’t interested in what the words are, just the colours they are printed in. As each word comes up, say aloud (it’s important you do this aloud and firmly) the colour the word is printed in.
The right side of your brain (note provisos in the book - the left/right split is not as simple as it seems) pretty well shuts down, leaving the left side in charge. When you suddenly get a colour that doesn’t match the word you can almost feel the gears in your head grunging as your brain attempts to switch into right brain mode.
This is known as the Stroop effect.