I'm interested in various areas of complex systems, and I often come across articles like these:

http://arxiv.org/PS_cache/cond-mat/pdf/0106/0106096v1.pdf

http://arxiv.org/abs/cond-mat/9804180

The main points are accessible in each (much less so the 2nd one though), but I'd like to be able to understand this sort of writing deeply, or even be able to do it myself.

What sort of studies would I need to undertake? Would a standard thermal/statistical physics class do it, or do I need something more drastic? Are there any resources along the lines "statistical physics for the social scientist" that are still rigorous and high-level?

(There's a question about "statistical physics for the mathematician", but this is almost exactly the opposite of what I need, funnily enough").