Great review, I especially like how you gently introduced MIRI and existential risk.

I'm curious about the paragraph on mental maps, the one with this sentence:

Our brains still seem to intuitively expect others to quickly understand us, often not taking into account the vast differences in individual knowledge that come about because of the great diversity of experiences and learning (unknown in prehistoric times) that modern humans have.

Which essay(s) does this idea come from? I've only read a portion of the sequences, and I wasn't able to find anything after a few minutes of searching.