Human language is thought to have developed 40 000 years ago at the most, millions of years after scientists believe humans first appeared. Although we lived on Earth successfully for millennia without even talking, never mind reading or writing, it makes it even more amazing that our lives are so totally dominated by language now.
Humans evolved as visual creatures but our aptitude for communication is so strong that psychologists have shown we now think in words as well as images. Our brains are so accustomed to using language that they will override other signals, even when consciously trying not to, ignore words they don’t expect to find and will convince themselves they can ‘see’ letters or words which aren’t there! These examples are illusions of both programming and expectation.
Write the names of different colours in big capital letters using different coloured pens or crayons. Write whatever colours you like as long as the pen you're using is not the same colour as the name you're writing. For example, BLUE can be written in any colour but blue, RED in any colour but red and so on.
The colour names should keep repeating, mixing up the colours until the entire page is covered. Get a friend to read out loud the colours you've used, not the words written.
This is surprisingly difficult with most people quickly getting confused as they revert back to reading the colour names rather than the colours themselves.
Read this sentence aloud:
Did you read one ‘the’ or two? Some phrases or images can seem so familiar to the brain that we process them automatically, without noticing any changes.