Whilst I can see some of the types that the author is discussing I feel that it is really a much more complicated thing that the five types. Sure you can pigeon hole people into these types, but I don't think that it works in all cases. At various times I have played characters in 2/3 of the types descibed. Very often I try and look to go for characters that I have not just played in games.
Interesting post and helpful that it considers how complicated all the interactions get. The material presented was OK when it came out, but wouldn't be thought academically valid now. There are a handful of researchers posting or publishing with recent evidence, e.g. this basic framework for a psychology of Tabletop RPGs is based on the latest science and there's a recent post by Michael Tresca on Sarah Lynne Bowman's work. Some researchers, including Sarah, are easily contactable via the FBook RPG Advocacy group.
Thanks for getting off your backside and getting into the science - the more the merrier