Last week, I was at my friend Elisa’s house for dinner and showed her and her boyfriend Victor my stereoscope and Snowman mirror exercise.
I expected they would see something different in the stereoscope than I would, but what shocked me is that when one of them saw the image in double, the other saw it in single. What? How could two people with seemingly 3D vision have different experiences with the stereoscope? When I told the optometrist the next day he asked, “How do you know they are really normal?”
He was right! I had no idea I saw flat until I read Dr. Oliver Sacks’ New Yorker article, Stereo Sue. So, if I didn’t know I wasn’t normal, it’s possible my friends don’t have such perfect depth perception either!
Normal is just a frame of reference, right?