Good article, but disappointed to see you cave here, Sean. There is a fair amount of scientific research and literature now to suggest that introversion/extroversion IS highly genetic.

It IS a spectrum. AND it's set in stone (to the extent the data written in our genes is equivalent to writing something in stone…either can be eroded over time with water/epigenetic factors.)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5563732/
https://www.jneurosci.org/content/32/50/18087.short
https://www.discovermagazine.com/mind/are-the-brains-of-introverts-and-extroverts-actually-different

I’m a very curious creature.