What makes you say that? I ask because I've also become slightly sceptical of the idea. Is there real, empirical evidence for people being one or the other?

I remember hearing someone on a podcast (I think it was Ramit Sethi) talking about "Introvert Porn", where he's saying there's all this stuff online basically reassuring introverts that it's part of who they are and there's no point trying to change. The reality is that (in his opinion) social skills can be learned, and social interaction becomes less tiring when your social skills are better.

I'd love to hear any arguments for or against the introvert vs. extrovert theory, because I feel like I'm still making up my mind. I've always felt like an introvert, but I'd prefer to think of it as something that's in my power to change.

"A 2012 study completed by Randy Buckner of Harvard University discovered that introverts tended to have larger, thicker gray matter in their prefrontal cortex — a region of the brain that is linked to abstract thought and decision-making — while extroverts had less gray matter. Buckner concluded that this might be accountable for introverts’ tendencies to sit in a corner and ponder things thoroughly before making a decision, and extroverts’ ability to live in the moment and take risks without fully thinking everything through (which has its cons and benefits, of course)."

We have different brain responses to arousal hormones - which is what allows introverts to do the abstract stuff that extroverts can't manage.

What you win on the swings, you lose on the roundabouts.