As much as I innately agree with Brent's premise from my own experiences, I too would like to see some research. Especially since he even says:

"I can’t prove that good software respects people, but I can look at good software and show how it respects people. I can look at bad software and show how it doesn’t respect people."

(All the more important now that Gruber linked to this too: http://daringfireball.net/linked/2011/12/24/gamification.)