Well, be careful not to assume that the modern-day loner is the same as the Pleistocene-era loner.

I'm both somewhat shy and very much introverted. I don't like artificially-created social situations. But I'll talk at great length to family members and people I work closely with.

If I were in a Pleistocene tribe where basically I'm surrounded by 120 members of my extended family, coworkers, etc. etc., I'd probably talk a lot more. I like social interactions, I'm just uncomfortable in novel situations and I don't like small talk.