1. Evo Psych: Our instincts were formed in an ancient time when not knowing the social norms and kow-towing to the political leaders resulted in literal and/or genetic extinction. Perhaps altruistic humans who served causes other than our own were more likely to survive Savannah politics.

I find the case that post-agricultural humans are the result of selection pressures for neoteny to be fairly convincing: The 10,000 Year Explosion (a short, good book on recent human evolution) talks about this some I believe. Many have remarked that humans in general are neotenous apes, where selection for neoteny (and thus an extended period of the greater propensity for learning that's associated with childhood) led to increased intelligence, or more often vice versa. It's odd because whereas selection for intelligence pre-agricultural revolution may have led to neoteny, when the agricultural revolution hit it may have been that selection for neoteny (submission) led to greater intelligence. This led me to do a lot of thinking and writing that unfortunately I think I can't put here, because it talks heavily about racial differences. :/

However, maybe someone with more knowledge than me could speculate about the possible link between neoteny and autism? I did some theorizing but it's not convincing. (Ha, I just realized how odd it is that talking about autistic people as if they were a group of people wholly separate from the rest of humanity is so much more socially acceptable than talking about racial differences. I understand why that is -- genocides and antagonistic discrimination are more often based on racial differences (exceptions include e.g. homosexuality and minority religions), so talking about them is taboo -- but it's still odd.)