Reddit mentions of Vision and Art: The Biology of Seeing

This is actually true for most (all?) colors. When you look at a tomato you aren't actually seeing the red tomato in it's entirety. Rather you perceive one blotch of red that your brain "spreads" across the rest of the tomato until told otherwise by a change in contrast at the edge of the tomato.

Source (for my other post too) - http://www.amazon.com/Vision-Art-Biology-Margaret-Livingstone/dp/0810904063 This is a fascinating but little known book written by a Harvard neurobiologist that I read a couple of years ago. Answers a lot of questions you might have about how we, and other animals, actually see things.

If you're really interested in this, this book is a really accessible overview of why we see what we see, and explains this exact phenomenon:

http://www.amazon.com/Vision-Art-The-Biology-Seeing/dp/0810904063