For instance, since humans are not telepathic we don't have access to the thoughts or mood of another person. The only way we can discover them is by being told about them — or, theoretically, brain-scans

I think various people are better at mood detection via reading body language than brain-scans. Both brain scans and reading body language are cases where you have partial information and use that to do pattern matching. I have multiple experiences where I meet people who can perceive my own mood better than I can myself.

There are many times where I get a better idea about someone mood by hugging that person then by asking them verbally and them telling me about how they feel.