Empathy has a performative component to neurotypicals. If you are not acting as though you are empathizing, you have "no empathy" and are thus a strange form of psychopath. Actual psychopaths can pass the performative part of neurotypical empathy with flying colors because they are excellent maskers and mirrorers -- that is, of course, when they can be bothered to try at all.
Neurotypical psychology is deep, complex, and fascinating. They devote significant brainpower to constantly evaluating and testing other people's behavior against a constantly evolving set of rules in order to ascertain whether they are a member of the neurotypical's tribe or ingroup. The rules have to change and evolve because ingroup members will be able to predict how they will change, and so catch any outgroupers who have heretofore successfully infiltrated the ingroup. It's like you have a monster CPU with a lot of cores, and then devote half (or more!) of those cores to the world's most elaborate DRM scheme. We benefit because much of that CPU power is in us freed to do other exciting things, like programming or particle physics; but we also suffer because most of the people around us cannot attest that we are legitimate humans running a legitimate copy of the human OS.
Relatedly, I love Japan and I love the Japanese people but... Japanese society has one of the most elaborate, impenetrable set of social rules in the world. If you want to know why hikikomori are such a thing there, it's simple, really: so many more people are frustrated with their failure to conform to the elaborate ruleset it takes to simply be Japanese and tired of being flagged as impostors in that game of Among Us that they simply give up and withdraw into whatever brings them comfort.
I would have thought the main performance bottle neck to social calibration would be the unspoken mind-reading requirement that seems to be prevalent in American society.
Perhaps I'm wrong, but from what I know of Japanese society is that it's pretty blunt in its expectations. So there isn't this "mental searching tax" to make the "right" social choice that seems to be de riguer in the States. Everyday behavior in Japanese society has explicit procedures that don't change all that much.
As I understand it, social failure in Japan is result of one of two things:
The inability/lack of interest to follow these procedures (e.g. hikikomori, non-conformists, etc.), or following these procedures but with mistaken assumptions as to how the consequences would turn out (e.g. "herbivore" salarymen who have done everything right, but are unable to find wives like their fathers could)
That's interesting. A German friend of mine who's on the spectrum and had established a second life in Japan told me that Japan's explicitly defined social mores, and slightly more chilly and formal relations between people suit him much better than the Western default. His German buddies who also have one foot in Japan all seem like they're on the spectrum too, because of this I thought Japanese culture is a safe harbor for autistic folks.
I've commonly said that the Japanese are Germans to strangers and Italians to family and close friends. Sometimes as a quip I add that they're Irish in the bar, lol.
Japanese society is not really safe harbor for Japanese on the spectrum. It is, however, quite gracious to foreigners. As a foreigner no one will say anything to you, for instance, if you use the wrong honorific or something; most will be impressed that you can speak the language at all.
Once you've been living and working in Japan for some time and have started to assimilate, though, you are on and you've got to perform the appropriate rituals or people will start to think you're being aggressively rude.
I've generally had the impression that German society is itself quite procedural and legalistic. So much so, that I'm wondering how much of a difference between the two societies your friend and his friends perceive. Was that his only reason to go to Japan or were there others?
Well, for one thing, we Americans claim to value honest communication to each other in our personal relationships. Whether we actually live up to those values is a different matter, but my point here is the Japanese do NOT. Honne/tatemae is pretty ingrained into Japanese society, and you must avoid embarrassing yourself and, more importantly, your ingroup (family, company, club, etc.) by being too honest around outgroupers. The Japanese are so pressured to not lose face that they are actively encouraged to hide their feelings and intentions, even when showing them would be mutually beneficial. You see it in business -- the old saw about circumlocutions like "We will give your proposal the consideration it deserves" meaning "no freaking way"[0] -- but you also see it in modern Japanese drama. Taro loves Hanako and Hanako loves Taro, but they are from different social strata and their parents would be shocked to find out they're in love, so neither of them says anything and neither of them knows the feelings of the other. Plus Taro is going to America to play baseball and Hanako is going to medical school. Will one of them work up the courage to go against the social grain and the wishes of their family, and confess their feelings before it's too late? Or will they just say shouganai and go about their lives without ever knowing what could have been? That sort of thing.
So as a Japanese person you are tasked with not only following the rituals, but also sussing out from the vaguest of cues what your friends, family, potential mate, etc. are thinking because they're following the rituals too instead of engaging in explicit communication.
Regrettably, I had to learn a lot of this by reading; I don't have a lot of personal experience with this because I'm a Westerner. The Japanese are generally more willing to be open with foreigners because of the relative lack of social repercussions for honesty with foreigners than with Japanese. They don't have to be "on", they don't have to actively be Japanese in front of us and that makes for some interesting and refreshing barside conversation, lol.
[0] Earlier negative stereotypes of Japanese as being "sneaky" and untrustworthy are partially rooted in this sort of thing. They mask their true intentions to avoid embarrassment, but to Americans it looks like they're trying to trick or defraud us. And they see us as loud, pushy bulls in china shops who are unable to handle delicate affairs with any nuance, even if we're well-meaning.
Neurotypical psychology is deep, complex, and fascinating. They devote significant brainpower to constantly evaluating and testing other people's behavior against a constantly evolving set of rules in order to ascertain whether they are a member of the neurotypical's tribe or ingroup. The rules have to change and evolve because ingroup members will be able to predict how they will change, and so catch any outgroupers who have heretofore successfully infiltrated the ingroup. It's like you have a monster CPU with a lot of cores, and then devote half (or more!) of those cores to the world's most elaborate DRM scheme. We benefit because much of that CPU power is in us freed to do other exciting things, like programming or particle physics; but we also suffer because most of the people around us cannot attest that we are legitimate humans running a legitimate copy of the human OS.
Relatedly, I love Japan and I love the Japanese people but... Japanese society has one of the most elaborate, impenetrable set of social rules in the world. If you want to know why hikikomori are such a thing there, it's simple, really: so many more people are frustrated with their failure to conform to the elaborate ruleset it takes to simply be Japanese and tired of being flagged as impostors in that game of Among Us that they simply give up and withdraw into whatever brings them comfort.