Trooper5445 said:
It's a theoretical question.
The original question was whether or not personalities change or does the external environment make it adapt and use other parts not previously used. The person has expressed a different personality from the one before, though the question still inquires whether or no the underlying personality has changed.
This is a very easy question to answer, the question is likewise asking if change is possible; there's no explicit question about the percentage of people of a population and some such. It's simply, does it change, can it change?
Yes. The is a record of a man getting a metal mining rod shot through the bottom of his jaw and through the roof of his skull. He fully recovered, but was extremely volatile and impulsive, compared to the relaxed calculating man before (allegedly). Lobotomies also do this- brain damage that affects the function of the brain. The person will display a different personality. We don't know what goes on in people's heads, we don't know what they are thinking. ****, we barely know how our own minds work and that of our personality.
The change in this respect is almost indistinguishable from that of other traits being shown. It's likely that it's both. Though one may play a bigger part than the other.
All that matters is, is that personalities can change, we have data that seems like they do, but that same data would also correlate with the theory that personalities only reveal more parts, simply because we don't know what goes on inside the mind.
Personalities can change, if you think the mind is a physical thing.