Who/What are Social Introverts? Who/What are Social Extroverts?

According to the Merriam-Webster Dictionary, an introvert is defined as "a shy person; a quiet person who does not find it easy to talk to other people."  Conversely, an extrovert is defined as "a friendly person who likes being with and talking to other people; an outgoing person."  In reality, nobody is a pure introvert or a pure extrovert; belonging to one of these extremes inevitably could lead one down a path of headaches and self-destruction.  However, most functioning members of society tend toward one side of the spectrum or the other.  Whereas most individuals are introverts and/or extroverts at varying degrees (yes, one can be an introvert at one moment and an extrovert at the next), we still seem, somehow, to coexist in society.  As a self-described introvert, I am searching for the leading factors behind one's identification as either a social introvert or extrovert.  While some experts claim that such identification is a result of nature, or genetics, others dictates that it is a result of nurture, or environment.  I want to interpret for myself to see what the leading factors seem to be, and then I want to afterwards be able to investigate the thoughts and mental processes behind the behaviors of these two groups.  Why do introverts generally choose to keep to themselves?  Why do extroverts find the need to associate with the rest of society?  Moreover, I want to find out how the behaviors of members among these two groups vary depending on situation (group situation where friends are present, group situation where no friends are present, situation in which one is alone), and how society perceives the roles and importance of these two groups.  Personally, I currently feel that being a social introvert or extrovert may be a combination between nature versus nurture, that extroverts generally crave, if not, require more social attention than introverts, placing fewer restrictions on their behavior, that introverts may be found to exhibit similar qualities to extroverts when surrounded by friends, and that society generally favors social extroverts over introverts, even though one group is no more important than the other in value.  As I look deeper into these topics, I hope to be able to understand both social introverts and extroverts not only for the reasons behind their behaviors, but for the thoughts that run through their heads and their perceived roles in society.  I will continually update by blog as I receive the latest information and collect the most recent data from my research studies.  If you would like to learn more about the research methods that I plan to apply and the experts that I plan to consult, the other pages on this blog ("Research," "Mentors") will direct you to more in-depth explanations of my project.  I hope that my audience will learn alongside me and will appreciate the behavioral differences in introverts and extroverts as I take this journey into the world of social interactions, or the lack thereof.

Also, if you want to watch an excellent TED Talk detailing the strengths and powers of introverts, as well as the need in society for these individuals to receive recognition, please watch the twelfth video in the playlist on this website, shared with me by my English teacher (thank you, Ms. Hetrick!):
http://www.ted.com/playlists/171/the_most_popular_talks_of_all