count the letters “F” in the following text :
FINISHED FILES ARE THE RESULT OF YEARS
OF SCIENTIFIC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS ...
how many did you count ?
Count them again, just to be sure ...
no there are 6 SIX of them !”
For some reason our brain has difficulty in processing the word “OF” .
If you did find 6, you are next to a genius !