An ESFP friend of mine has basically the same intellectual horsepower (IQ) as me, yet our personalities are extremely distinct. I know this from administering three actual intelligence tests to said person (she was, by turns, willing, tolerant, and exasperated by the process), personally taking those same tests, and spending many years with her. On the personality front, the ESFP type is well established.
To go big picture with this, I wouldn't say that one is either born with a specific intelligence or a specific personality. That said, we probably have predispositions for these things, talent and temperament, such that deviation from genetics, brought about by will or environment, can only drift so far from baseline.
Someone with a predisposition for shyness or introversion will retain those traits in some manifestation in spite of active efforts to become more extraverted or an environment that rewards, or only tolerates, extraversion - thwarted still, I think that introverted person would experience an avalanche of chronic stress, become isolatist, and so forth.
With intelligence, maybe an example would be ideal. I went to high school with this complete flake - he never did his homework or studied for tests, and basically dedicated his time to smoking various drugs and screaming depraved crap in class. However, both his parents were neurosurgeons, he read and wrote recreationally, and essentially attained a perfect score on the SAT with no intention of going to University. He failed half of his classes Junior year and was thrown out. By all accounts the kid was not widely thought of as an intellectual, and yet, despite his choices, lifestyle, and general environment, some morsel of his parent's gifts rubbed off on him.
Clearly though, if one was waterboarded for months or sedulously wacked in the head with a mallet, the personality and intelligence would be blunted. Meh, no argument is perfect...and not every one is short.
