I must admit: though I'm certainly not at any level of authority here, I think most of the members would agree that CT is just a theory, and it is based mostly off of other theories belonging to more well-known psychologists. What's worse, it seems to me that many people, upon first glance, would write this off as pseudoscience (and frankly, I don't blame them).
However, there is some science behind this, and here are some things you could check out:
CT's main inspiration is the writings of Carl Jung, who first came up with the theory about psychological types and the eight functions. All the schools of thought involving the 16 types - MBTI, Kiersey, Socionics, etc. - come from him. You might get a few helpful results if you Google him.
There is also Dario Nardi's research on different areas of brain activity. Here is a PDF on how CT might fit into his theories.
Finally, here is an index of (most of) the articles/threads on this forum, which includes a post on CT's potential for falsifiability (which is important to any scientific theory).
That's all I got, but I hope it was of some assistance to you! Maybe people who are more knowledgeable than myself might come by and provide some info (fingers crossed!). Anyway, good luck on your quest for understanding!