I remember not really “getting” these illusions when I was a kid. I just didn’t find them interesting, it looked too straightforward.
The idea of a “2D screen inside our head” is not our natural intuition. Before learning about these things, I just felt that I simply percieve the environment around me. I don’t see a flat pixel grid in front of me when I walk around, I rather have a model of the environment that I continuously update and I percieve the objects “from where they are”, just like I feel leg pain as if it were “in my leg”, despite the fact that pain actually happens in the brain. I see objects where they are in the 3D model, not where they are on a virtual screen.
The screen and pixels analogy may be so prevalent in modern times because of the TV, photos or even earlier realistic paintings. But early art was not really realistic, which I think either shows they were
not skilled enough to draw realistic art with perspective distortions and shading, or
they didn’t think of vision the way we do today, they were more focusing on the objects and their prototypical shapes, rather than their position in the visual field and the “actual colors”.
The second explanation seems more plausible to me.
These illusions are only illusions if you take the “2D screen and pixels” view of vision. Now that view is also important for technological applications, and it’s also biologically relevant (retina cells are sort-of pixels), I’m just saying it’s not really an illusion against builtin intuition.
That’s a triad too: naive instinctive signaling / signaling-aware people disliking signaling / signaling is actually a useful and necessary thing.