@Neonatal RRT
I think they're both results of the same mechanism.
( i.e. something like a "confounding factor" in causal inference:
Confounding - Wikipedia
IMO people (including ASDs) are "hard-wired" by evolution to look for differences from their own set of "human-centric" norms.
Which, if true, implies there's a question that's highly relevant for ASD: why
don't those of us brought up together with NT peers in a culturally straightforward environment "pass the first-impression tests"?
Whatever it takes to "pass" has to be learned quite young, but it's not explicitly taught, so it seems likely it's a result of the set of imitation behaviors that young children use to learn language, behavioral rules and guidelines, "body language", social interaction, etc.
My personal theory is that there's a gap in our "innate imitation instincts", and that it mirrors (or is mirrored by) the empathy deficit that I'm starting to think is our only common trait.
Well, it's not just your personal theory, and appears to be correct. Most psychologists on the topic have pretty much paraphrased this same idea that most NT children simply "pick up" these nuanced social and communication cues at a young age, often before the age of 5, especially little girls. Boys tend to have a delay in their frontal lobe development, and is why "boys can be little jerks" well into their teens. Many NT teen males will struggle with facial recognition of emotional states per PET scans and score low on the "faces test". Furthermore, females typically have a more pronounced communication between the right and left hemispheres than males, as most male communication in front to back. This has been demonstrated several times with PET scans. It's those frontal lobes, the prefrontal cortex, and the anterior cingulate cortex, development and functioning that is most important for socialization, picking up subtle communication cues, decision-making, and behaviors. It's the communication between the hemispheres where the typical female is often superior to the typical male in terms of accessing and recognizing emotional states.
It is for this reason that some psychologists once thought that autism was an example of the "extreme male brain". It also suggests reasons why female autism has been historically difficult to diagnose, as their brains are better suited to masking their condition. I have 2 female autistic co-workers and I had to be told by them they were autistic, because frankly, I would have never known. As opposed to my male co-workers who are autistic, where I can pick it up from a mile away.
Throw in an autism condition though, where the micro anatomy is associated with areas of too many and too little synaptic connections, abnormal conductive and connectivity patterns, abnormal layering of the neurons, abnormal concentrations of glial cells, pro inflammatory conditions (chronically elevated homocysteine), poor methylation of B vitamins, poor creatine metabolism, neurotransmitter imbalances, too few serotonin receptors, genetic abnormalities in the genes responsible for serotonin and dopamine binding, transport, and turnover, and a long list of other confounding factors. Obviously the autistic brain is working, but quite differently than a NT brain. Obviously, this accounts for the long list of things we might perform better than a NT, and things NTs perform better than us. In computer speak, our hardware and software is different. You can't run software that is specific to a Mac on a Microsoft machine and vice-versa.
With regards to imitation behaviors or mirroring, this is something that autistics and NTs do, or at least attempt to do. For example, in the case of empathy, I am very sensitive to another's strong feelings of grief (I will cry with them) or anger (I will match their energy). Music puts me into a matching "mood". Sad scenes in a movie (I will be the first to cry). The "mirror neurons" appear to be quite functional. However, it's the day-to-day situations where we may be speaking with each other and they are cueing in on all the subtle nuances of my body language, facial micro-expression, eye contact, voice inflection and tone, that frankly, I might not pick up on theirs very well, and two, my own non-verbal language/tone might not match my intent. Then it comes down to reciprocity. When one person does not mirror a specific "state of mind" or "tone" during a social interaction, it's then when the other person is going to sense that something is "off". Personally, I happen to be poor at this reciprocity unless the other person's emotional tone is rather extreme.