This is a theory on how an extrovert can became and introvert and possibly vise-versa. This transformation is actually a medical thing, it involves the hormone dopamine and its receptors and how they function in the brains of introverts and extroverts.
This first post thought will discuss the actual terms “extrovert” and “introvert” The next will describe how the transformation would work.
The terms extrovert and introvert seem to be misunderstood often so I just want to clarify my definitions of the terms before I go further. My definitions are based on this video by interpersonality on youtube http://www.youtube.com/watch?v=cnN-ozQNDbk&feature=g-hist , and by this book The Introvert Advantage by Marti Olsen Laney, PsD.
So these two examples agree that an introvert is simply someone who is energized by ideas, thoughts, concepts as they gain understanding of them, (maybe things but not quite sure). So if they can convert an environmental stimulus into a thought that is intriguing to them, it makes them feel energized. Extrovert meanwhile are energized directly by the environmental stimulus(usually it would have to be a positive stimulus).
How does this relate to social interaction? : Here is an example. When you complement an extrovert , they will immediately feel energized and show their thanks. When you complement an introvert they will process it internally, analyze it, and if they can relate to the compliment in a way that is energizing to them they will feel energized and probably show their thanks. So with Extroverts they are energized because they were complimented, while introverts are only energized if the complement itself is meaningful to them which would probably depends on a lot of variables.
So as you can see, extrovert/introvert has nothing to do with being social or anti-social, However, because in most communities there are a disproportional amount of people are extroverts, and so introverts are less understood, introverts may become more socially isolated. Also I will add that extroverts gain energy directly from social interaction, giving and receiving, while introverts are energized by themselves and need time to build the energy periodically through thinking and this will take up time leaving gaps between interaction. Not anti-social, but arguably less social.