alt Hacker News>It seems pretty obvious to me that this also existed in older times. It's a pretty well established and reproducible big five trait.
Parent is not saying there weren't introverts in the 80s. But it wasn't a big thing, and people didn't make it their whole personality, in the numbers they do now.
the last 5-10 years has seen an increasing number of people claiming "i'm an introvert" as a big facet of their personality. it's weird that there isn't a corresponding surge of self-identification as an extrovert (because if there's anybody that would be doing something loudly, it'd be extraverts).