Introversion and extroversion is not a static spectrum, it slides depending on circumstances. If I'm in a work environment, or somewhere action-oriented, or di

Introversion and extroversion is not a static spectrum, it slides depending on circumstances. If I'm in a work environment, or somewhere action-oriented, or discussing something practical or intelligent, I am the biggest extrovert on the planet -- especially if the culture includes straightforward and honest communication. But if I'm in a culture of passive-aggression/double-talk/"nice" or I'm discussing philosophical or otherwise non-practical matters (e.g. "oh. My. Gawsh. Look at how cuuuuute that puppy is") or the people I'm conversing with have zero dimension or breadth to the topics they choose to engage with: I don't fucking care, and my interest in engaging is zero. The confounding factor is that most introverts like to talk about specific subjects that are uncommon interests while extroverts like to talk about specific subjects which are common interests. I think you're getting close to an accurate general statement, but your points are wrong. I can bring introverts out of their "shells" by engaging with them on topics that interest them (at which point they will likely overpower me) and I can put extroverts into their shells by forcing a topic that they have nothing to say on. The thread that connects all of this is interest. Introverts have a set of interests that is not conducive to general, everyday conversation, while extroverts do. From there you can have knock-on effects like confidence, social outlook and initiative, and other things that cascade throughout the years that make the divide between the two more apparent and may generate specific differences (e.g. fearful of criticism or not, etc.).