How Can We Develop Good Characters If We Don't Understand Ourselves?

I'm traveling for work today and don't have much time to post, but I wanted to bring to your attention this incredible article I saw in Slate about brain injuries and behavior.

It makes for some disturbing reading, and by the end you'll see it raises questions about assumptions in the way we apply the law, as well as about more abstract philosophical topics (such as free will) that nonetheless can affect the way we see ourselves, others, and the world. We could talk about the many subjects it raises for days, from many different angles. But because it really gets to the core of what makes us who we are, I thought it also raised some interesting - if less societally pressing - questions about literature and characters.

What if you had a character like one of the injured people in the article? Someone whose behavior changed in undesirable ways as the result of a trauma? Someone for whom the changed behaviors were not a choice, not a failure of willpower, not even tied to emotional turmoil that others couldn't clearly see...but linked up with a physical injury to the brain?

How would you convey what was going on in that person's head? Do you think readers could develop sympathy for such characters even if they engaged in totally antisocial behaviors? If so, would the characters deserve it? (I have vague memories of reading about murderers in thrillers and horror stories who are being tormented by a brain tumor...but you're still not supposed to feel bad for them. And the mentally-ill serial killer is a cliche.)

We all know what works in creating good characters - not that it's easy to do (not at all) - but at least as readers we know it when we see it. But what if our impressions are based on flaws, founded on larger flaws in the way we see ourselves? Then would a true character perhaps be more fickle, more robotic, more the slave of physiological urges (and physical traumas) than a good character?

So much to say, so little time right now. I leave it to you. Of course it's easier simply to ignore all this. But play with it in your mind for a second, and let me know what you think.