Interesting how the thesis of the article is the exact opposite of the thesis of this one, which was posted to HN a few days ago:
http://aeon.co/magazine/psychology/humans-are-wired-for-nega...
http://aeon.co/magazine/psychology/humans-are-wired-for-nega...
This article talks about frequency of usage. Perhaps someone can dig deeper and figure out where they get their frequency of usage data from?