The "look at me" approach to reading humans is painful, literally, for me -- and I know I am not alone. Considering many cultures dissuade direct eye contact, it must be assumed individuals in those cultures concentrate on intonation, gesture, and other non-verbal signals. Even personal space varies culture to culture, so the signals are not universal.
When I discuss this with other adults, including the non-verbal (which I am only under stress), it seems many of us focus on the mouth to compensate for "hearing too much" background noise and distractions. If I'm in a public space, I have to concentrate on the mouth to make sense of the spoken words even though I have excellent hearing. I simply end up confusing conversations around me with what is being said in front of me.
I end up finding myself reading journal articles and wondering why the conclusions of other researchers is often so far from my experiences and those of others I know. I often think at least interviewing adults with various deficiencies would alter the conclusions being reached.
My own research has centered on pedagogical concerns at secondary and post-secondary levels, where the social interactions are often as important as any course content. I have to resist the urge to remind other researchers and experts that getting me to "mimic" and "appear" more like everyone else is only a coping strategy. Its definitely a reminder that I am different and "deficient" that I must adapt to make others comfortable... but it also matters if I want to be successful.
I don't mean to sound like a radical on the matter. I simply want to remind others that simply because I can learn to outwardly do something doesn't really make me any more content or improve my self-image. In some cases, quite the opposite.
So, I do think decoding skills matter. They matter a lot in society that values "personality" and "charm" as much as knowledge or skills. I certainly appreciate the value of such skills. I simply wish some experts would not confuse successful mimicry / "faking it" for actual, internalized experience.
I'm quite good at reading faces 90% of the time, now. I've also memorized how to respond situationally. Example: Student looks confused during lecture (raised eyebrows, tilted head, tight lips). Reaction: Ask the student a question or prompt to confirm comprehension of lecture materials.
Good skill to have. No question about it... but it has always required analysis and conscious thought. I'm 40, so that's a lot of practice at it. Still, the delay in processing is and always will be noticeable to some people. That's okay, because that's who I am.