In his book, I am a Strange Loop,Douglas Hofstadter suggests that our identity comes, in part, come feedback that we get from parents, teachers, friends, books, movies and other inputs. We take these in and try some and discard the rest while putting together an identity that is really a pastiche.
I think of our identity, in these terms as concentric circles.
Identity A I got from my parents, Identity B from my teachers, Identity C from church, Identity D from junior high school and so on.
I realize it is useful to think of characters in the same way. The multiple levels of influences that came together to make them unique persons.
Also, we can trace how the identity as a writer– or lack thereof, developed. I started writing poetry as a fourth-grader and got good grades. I started journaling in ninth grade and made watching my thoughts a near-constant practice. I handed in a novelette in eighth grade and that teacher suggested I might be a novelist. The poetry is the most reinforced by time and feedback, the journal by the sheer amount of time writing it, playwright by feedback the intense experience of writing, and lastly novelist.
Novelist lacks the time and the feedback to become a definite identity. I am starting to think how identity might be consciously changed– but I have just started.