I believe the more intelligent you are the more control you have over yourself. That's why you usually see a dumb ass redneck with no shirt getting arrested on Cops for smacking their girlfriend for doing his meth. Smart people know better. The more intelligent you are, the more respect you have for yourself and the more introspective you are about how your personality develops. Intelligent people are also much more aware of how they are perceived by others and make an effort to be better today then they were yesterday. Less intelligent people tend to not give a shit about anything so long as they "gets what they're due".
Besides, our personality mainly develops in adolescence. Sure there are happy little kids and troubled little kids, but during adolescences we start to find things interesting on a more intellectual level. Some kids like trains, others like airplanes. Some like sports, others like reading. It's not a decision we make, it's what we find interested and what evokes emotion that drives us to want to learn more about things.
After adolescences, when we are adults, after we have already developed our likes and dislikes, we then have control and responsibility for your personality.
