You know those color-blindness tests you see on the internet? Like, people with red-green colorblindness won’t see the number 33 in this array of dots, or whatever.
Are there other things that disease makes the senses unable to comprehend? Like, for example, a person with [insert terrifying disease here] will look at this picture and see [insert something cool here]; whereas a healthy person will look at this picture and see [something else, or randomness, or nothing].
There are things that can happen to your brain that produce strange effects; Oliver Sacks’ The Man Who Mistook His Wife for a Hat is full of them. I remember one very educated man who found it quite frustrating that he could see the parts of things but not the whole - for example, see that an item had five closed-ended tubes of unequal lengths attached to a larger sort of torus arrangement, but not be able to see it as a glove. I don’t know if that counts as the sort of thing you’re looking for.
That’s pretty much what I was going to say - yes - there is a wide range of perceptual disfunctions - people who can’t see moving objects, people who can’t see objects unless they’re moving, etc.
Prosopagnosia. And to clarify - they can recognize a face just fine. They just have difficulty telling who it is. They can easily recognize distinctive people, e.g. giant noses, purple hair. This can be caused by brain damage, but we are discovering that some people have had it their whole lives, and it isn’t terribly rare.
Akinetopsia is can’t see movement.
**Simultagnosia **- inability to perceive more than one thing at a time. A “thing” can be one discrete object, or one “thing” that is grouped, etc. - depends on the situation
—See also, Bálint’s syndrome, of which simultagnosia is one symptom
Hemispatial neglect - can only see one half (vertically divided) of space. Most commonly, they can’t see on the left hemifield. This doesn’t mean that it’s a black space or they are blind there, but literally they don’t notice anything over there. A common example is that if you give them a plate of food, they will eat only half. If you ask they to finish, they will until you spin the plate 180 degrees.
“The Man Who Mistook His Wife for a Hat” doesn’t really give diagnoses, but he likely has visual agnosia as well - being unable to recognize an object, even if you can identify by touch, or explain how to use it. Related is anomia (we’ve all experienced this at a non-clinical level), where names of things can’t be recalled. This is more related to aphasia though - the many difficulties in understanding or producing language.
until you spin the plate 180 degrees.