questions authors should ask their characters is "Do people understand you?" - and then if no, what do they not understand about you?
Should characters be understood? Probably not. It makes for tension. Tension, properly handled, makes for a good story. It is what I want as a reader. Do we understand people in real life? No, we misunderstand them all the time. I have probably misunderstood Nicola so many times she wishes that I would stop leaving cat hairs scattered across her pages and just keep my writing to myself.
Now one of my questions of characters would have been, indeed is, "Do people understand you?" and then "why do they not understand you?" - is it you or is it them or is it a combination of both?
As human beings I believe we tend to think of the world in stereotypes. It allows us to categorise large amounts of information into meaningful chunks. If we do not do that then we are in danger of getting what might be called "information overload". I remember an occasion years ago when I was talking to the two daughters of a blind man. Their father was not in the least bit musical. He was, to all intents and purposes, "tone-deaf". Despite this they still persisted in the belief that blind people tend to be exceptionally musical. It was their father who was the aberration.
There is, of course, the same range of musical ability among people with visual impairments as there is in the rest of the community.
If we want to use a person with a visual impairment in a piece of writing then, as authors, we need to confront that stereotype. Does it hold good for the character? If so, why? If not, why not? How do we make it believable. Who holds the responsibility for the way in which the character is viewed in what we are writing? Is it the character by their actions or the character who is interacting and responding to those actions? Why does it matter to the story?
I doubt I do all that consciously. There are things I do not know about my characters and there are things I know that surprise me. There are things I want to know that elude me but I have come to recognise that these are often sheer curiosity on my part. They are not essential to the story so why should they let me know?
For me the "why" is as important as the "what", perhaps more so. Why are you the way you are? Why do people react the way they do?
I need to confront stereotypes.