Background as in what, context?
As in you need to spend some time with that person and get a feel for their ticks and naunces.
However....have you heard of microexpressions? They are INVOLUNTARY facial expressions that happen very quickly. Since they are involuntary, if you learn to read them, you can get a reliable indication of how that person is truly feeling.
Well sure. That's part of the reason of how you can tell people's emotions. But you can't use that against high level people, like you said. For example, When I haven't socialized in awhile my facial expression is going to be stiff and my voice will not sound confident. But when I get used to it my facial expression relaxes and warms up and my voice resonates and I no longer change facial expressions unless I deliberately want to show a certain emotion like skepticism, anger, arousal, warmth, etc. It's all a matter of not being affected by emotions and men who are good with girls do this very well.
As well, finding out how someone is feeling is better accomplished by observing multiple expressions of their body language. People who are learning how to control their body language are trying to "fake it till they make it." The problem is that their inner state will betray them and involuntarily cause their body to express itself in an incongruent way. For example, I could see a guy who is portraying himself as comfy and relaxed with his environment - taking up lots of space and sprawled out. But one look at his eyes will betray him. Unconfident, submissive people will have this wet look in their eyes. You can't change that unless you're actually truly not unconfident.
Yeah, for sure. Me personally, I've worked on myself long enough that my fundamentals stay stable regardless of situation with the exception of my voice. My voice is pretty good at indicating if I'm feeling comfortable or not, then again it's my least worked on fundamental which I'm planning on rigorously training it soon.
That's why I said there are other things involved. Seems to be a combination of your body language, voice tone, facial expressions, eye contact, and the person's actions. Another thing I haven't seen you mention is mirror neurons. If someone's portraying themselves a certain way but it's not the vibe you're getting from them, something's up.
My question is, why study something like this? I've always gone through life being pretty good at spotting people's true intentions and I just figured everyone else was the same way unless they had Autism. Is this not the case?
So whether you study it or not, you'll still get the same vibe from a person regardless, is my point.
Cacc