Have you ever did the old, “I’m going to look at someone through my fingers and pretend to squeeze them”? I know personally that is something that entertained me (and still does) for many hours of my childhood. But I always wondered why it seemed like the person never got any bigger or smaller and how they always seemed to look the same size when I squinted my eyes. So when reading the chapter in the book about depth perception, my questions seemed to be answered. I never realized it was pretty much just because of the scale of the size of the object, or the size- distance scaling equation. It has everything to do with proportions of the object and how you really see it.
this picture is proof that I still do this to this day. =)