Where does that terminology come from?

The work of Carol Dweck, see the book "Mindsets". I also recently wrote a blog post that ties her work together with Seligman's 3Ps/optimism model, and my own "pain/gain" and "successful/struggling" models, at: http://dirtsimple.org/2009/03/stumbling-on-success.html

I expect to be writing more on this soon, as this weekend I found a connection between the "fixed" mindset and "all-or-nothing" thinking in several areas I hadn't previously considered candidates for such.