Go here. Take the 30 second exercise. This optical illusion freaked me out! (Thanks, Brown Belt, for sending me the link and to John Sadowski for being brilliant.)
Say the color of these words as fast as you can:
Green Red Blue
Yellow Blue Yellow
Easy, yes? Now try this one, say the color, not the word:
Blue Yellow Red
Green Yellow Green
Did you go notice the lag? It's one of the exercises used to assess your "brain age."
My brain has aged quite a bit over the last few weeks of studying here Plymouth. I've living on only a few hours of sleep, and after staring at the computer screen for hours on end and learning new programs, the whole world begins to look like John Sadowski's photo BEFORE you move the mouse over the image!