Talk to ptgatsby about FFM and the factors that correspond to MBTI (especially E/I). I have not really seen E/I change that much at all from early childhood. We simply see coping factors change, and/or ability to deal with situations that are not the optimum one. (i.e., introverts learn how to gauge their energy reserves or develop socializing skills to offset their anxiety, extroverts learn to pace themselves and also give space to introverts to participate, etc.)
Without going into the details, there is a review that indicates that personality as measured by the Big 5 tends to be somewhat consistent. But the fact that it tends to be consistent does not mean that it is impossible for it to change.
What data? (I don't necessarily disagree, I am just curious to know if you had any specific sources in mind, or if this is the culmination of your personal experiences throughout life, or what exactly.)
There are a number of articles on this that you can find from google scholar.
ptgatsby said:Most personality can't be changed, in theory, because it is genetic and biological (ie: biology, not chemical).
This is debatable... (without wanting to go in a nature vs. nurture debate, bored to death of it).