Is personality the result of early childhood learning?

We don't remember much of what happened to us in the first 5 years but our brains develop and learn a lot. I would expect these lessons become internalized unconscious behavior or "personality". Children "try things" and if it yields what they want the behavior is reinforced.

We like to think of ourselves as "fair and logical" but these are also learned, not an implicit part of how the brain works.