Since replacing my eyes’ lens there have been a few times – every week or two, call it – when I see an hallucination out of the corner of an eye.
They move. Fast. And are gone.
What was that?? A rabbit? A car? A leaf falling where it shouldn’t?
They always seem like … something. Something identifiable.
But then they are gone and forgotten.
Nothing to see here, folks. Move on.
Coupled with more apparent oddities of new lenses – weird depth perception, fluid focus, bright blue world – these hallucinations do show that vision is not a camera.
So, now I wonder – just where in the brain is our GPU? Hey, it’s no new story that what we see in our mind’s eye is highly processed. But some gizmo has to render that highly processed information back in to pixels. That gizmo is impressive. And it’s not surprising the works of such a gizmo would be gummed up when its raw input is changed.
(Yes. I also believe that “gizmo” is a misleading representation of this aspect of the vision system’s architecture. It might make more sense to think of the image in our head as being heavily shopped. With parts of the image variably selected from many shopped alternatives.)