I have to say - that optical illusion is freaky as hell! I now don't understand how people who can see images aren't constantly distracted...
They can. My boyfriend is an artist and can literally paint from memory - just like painting with a very detailed photo in front of him. It sounds incredible to me but this is the 'normal' way of being apparently. I posted a question about it on facebook some time ago and ... it was just me that couldn't!
I read an article in New Scientist some time ago now that said, and I paraphrase here, "There are these strange people who can't visualise things". And I thought, "wait? what? There are people who CAN really visualise things without seeing them??!!" The idea just seems nuts to me at the time, how can you see something that's not there? - it made no sense. I remember listening to a piece of music (before this) and an artist friend of mine was telling me about all the pictures it conjured up in her head, and I just thought she was slightly mad (she is ;) or maybe it was an "artist thing", and didn't worry too much more about it. After reading that New Scientist article I asked my boyfriend if he could make real pictures in his head and he said "yes, of course" and proceeded to tell me about what he could see and how he could basically paint a whole complex scene in his mind from nothing. FREAK! I posted on Facebook about this, I was interested in how people actually saw things - I was curious as to whether it was a separate 'screen' or if they were superimposed over what they were actually seeing. I never really got a satisfactory answer to this TBH - maybe it's hard to explain.