Perhaps more accurately, “What you think, you see.”
It’s always worth reminding ourselves that we don’t actually “see” anything. Photons strike our retinas causing nerve impulses to travel to various parts of the brain. (There is processing behind the retina, so sometimes no impulses get sent.)
In any case, these impulses get mixed up with all the other activity in our 86 or so billion neurons in the brain, involving in some cases thousands of interconnections, each. The result when it finally hits our prefrontal cortex is an “observation.”
Lots of things can go wrong, a fact for which we need constant reminding. Here’s a good one.
You may have seen this recently floating around the Internet. Go to http://www.psy.ritsumei.ac.jp/~akitaoka/color12e.html and look at the last illusion. If you have a color picker that will tell you the RGB values for any pixel, you can verify Dr. Kitaoka’s claim. Or just blow the thing up and scroll back and forth.
The same phenomenon happens out in the real world, where the patterns are not static pixels on a page but evolving scenarios often with lots of people. If you can be fooled by pixels-on-a-page, think about what happens out there. Oh, and the pixels aren’t actively trying to deceive you.
In the OODA “loop” sketch, Boyd tried to capture this with the “implicit guidance and control” feed from orientation back to observation:
We can mine a little more from this experiment. Once you’ve decided that you see blue and green spirals, it can take a fair amount of effort to convince you otherwise, even though Kitaoka tells you what the RGB values are. You may have noticed this. Now suppose you didn’t know the real colors and just saw the figure cold.