Freud compared the mind to an iceberg. Our conscious is everything that we see above water and our subconscious is everything below the surface. I first became that much of writing was subconscious some months after finishing my third book. I realized I'd writing 100,000 words or so about hunger. Yes, it was horror with a decent monster, but all that time I was writing about monsters, I was also writing about hunger. But not, the emotion limited to the intake of food. My soul ( or some deep part of me) was / is hungry. To my own ears this sounds rather melodramatic but it's true. So I wrote a whole book about hunger and not one word of it was conscious. Now that's not to say, I won't bring the themes out as I edit it.
The unconcious is a nonverbal beast. It has no words of it's own so it enters out lives in odd ways. We do things and we don't entirely understand why we're doing them.
I have a theory that what drives humans to dance, sing, and write stories is an unconscious need to share our experiences. Carl Jung, a psychologist, purposed that all of the human experience is contained in the collective unconscious. I purpose that the collective unconscious is very real. It is all around us, in the music, art, movies and literature we share. How else can we explain why one mention of fire by Robert frost calls to mind Dante's inferno? Ultimately, I think transference of knowledge is at the core of what drives us to tell stories, to read, to watch and to sing about them.