[KenjiCrosland]

MRI scans of accomplished meditators have shown significant changes in brain structure, as do players of certain video games. People do change--whether or not that's a matter of free will is a discussion you'll never reach the end of.

[suivix]

Although it changes it is still in the human range, close to your original personality, and the delta is negligible. Your brain is essentially the same.

[KenjiCrosland]

I'm not a neuroscientist so I won't argue that point. I think as far as self-improvement and personal growth is concerned, however it seems that at least on a surface level that people can alter their behavior. Again, whether they are hard-wired to do so because of brain structure I don't know.

[Revisor]

Your belief is a self-fulfilling prophecy. You won't change because you think it's not even worth trying.

And it works both ways - if you believe you can change in a meaningful way, you will.

See my post elsewhere in this discussion with two books on optimism and self-theories.