I think it is fair to say that they average person believes that seeing and vision is all about the eyes. In actual fact, a person could be blind but still possess perfectly functioning eyes. the eyes don’t see. It is the brain, or the person who’s consciousness is produced by their brain, which does the seeing, more specifically, the parts of the brain that are responsible for visual processing. I think they are mostly at the back of the brain.
Vision is the result of the operation of the eyes and also the brain, and neuroscience is more and more becoming aware that there is a great amount of normal and also unhealthy variation among brains. The brains of dyslexics don’t handle reading well. The brains of left-handed people are definitley different to those of most of us, but not in one uniform way. Some people’s brains are damaged or derailed in development even before their untra-uterine development is completed and they are born, because their mother smoked during pregnancy or drank alcohol or had some misfortune such as catching one of the many infectious diseases that can harm a foetus. The genes that we all inherit or mutate can affect they way our brains work in profound ways, including visual processing. Prosopagnosia or face-blindness can be inherited and can run in families.
Your brain is different to my brain in countless ways that have an impact on the way our minds work. I often experience music as a coloured form of entertainment. You probably don’t. I can’t help but remember the faces of people that I meet, even if they are people who play very minor roles in my life and are not expected to be met ever again. Here’s an example. I took one of our kids to the Royal Show recently. One of the attendants at one of the animal pavillions was kind enough to let my child collect an egg that one of the prize-winning special-breed chickens had laid in it’s cage. He was a nice person, but there was nothing particularly memorable or different about his face or appearance, and I never expected to meet him again. Some hours later I involuntarily spotted his face among the teeming crowd of scores of show visitors surging down one of the streets in the showgrounds. As is usual, I consciously avoided looking like I had recognized him, lest I be seen as some kind of stalker weirdo. Is this kind of experience a common one? A rare one? Who could know for sure? One thing that I do know is that it was a complete surprise when on a whim I found the Cambridge Face Memory Test online and did the test and found that I had gotten a perfect score. At the same website for the first time I saw the term “super-recognizer”. What is a super-recognizer, I thought? Could I possibly be a super-recognizer? I’ll Google it!
It appears that I have some kind of visual gift, but I had no idea. People who have the opposite level of ability in face recognition also sometimes have little awareness that they are different from the norm. I recall seeing one of the prosopagnosics who were interviewed on the US version of 60 Minutes saying that before her diagnosis she had thought she was just not good with people. That’s a very vague idea of what the issue is. That is a remarkable lack of insight into what was going on in her life, but of course, I’m not blaming her. If you are looking for examples of visual or sensory processing disabilities that people can have but be unaware of, there are clearer examples to find than prosopagnosia. I’ve read that stroke patients can be unaware of a loss of vision in half of the visual field of one or both eyes (hemianopsia) or can be unaware of a loss of awareness of one side of space (Hemispatial neglect). People who have one form of colour-blindness, Anomalous trichromacy, can be unaware that their visual perception is different. Doctors even have a term for a lack of awareness of disability or deficit; Anosognosia. Psychologists have a term that seems to cover similar ground, plus some; the Dunning-Kruger Effect. In the Dunning-Kruger Effect people who lack skill in some area may mistakenly believe they are skilled or even above average, while people whose skills are excellent may lack the appropriate self-confidence to go with their high ability or expertise, because they mistakenly or unknowingly assume that everyone is operating at their level and they are just average. In my experience, the Dunning-Kruger Effect applies to visual processing ability. I’ve seen people time and time again mis-identify things such as plants, vehicles or animals with confidence, and time and time again, I get told that I’ve got a great eye for detail. Sometimes it seems to me that it is instead the case that I’m inexplicably surrounded by people who are borderline cases of cortical blindness, or are way overdue for an appointment with an optometrist. If you couldn’t see properly, would you be the last one to know?