clipped from: www.livescience.com   
Can a Type-A overachiever become a slacker? How about the guy who can't hold down a job to save his life-could he transform into an adrenaline-pumping go-getter? A leading expert in personality psychology says yes: Personality can change

The once accepted idea that an individual's personality is set in stone is, well, changing

You read about this twin research where these people who have been raised apart have remarkable similarities," said Carol Dweck, a psychologist at Stanford University. "They married women with the same name; they named their dog the same thing; they both build little ships that fit into a bottle and they show up to their reunion wearing almost identical clothing

The implication there is that it's all programmed in," that personality is permanently stamped into our genes.

My point is that there's a really big in-between area that they don't talk about, and these are the crucial beliefs that people develop as they grow and learn