(I didn't downvote the grandparent.)
I disagreed with that because it appears the difference between chimps and humans is that humans are better at social things, including modeling other humans. Chimps can learn, but they don't teach- probably because they don't understand that their children can learn.
The claim you're making seems subtler- that if you divide a chimp's ability to model reality by a human's, you'll get a lower fraction than if you divide a chimp's ability to model chimps by a human's ability to model humans. I don't know enough about their ability to model reality, but the impression I get is that chimps are pretty clever.
Chimps can learn, but they don't teach- probably because they don't understand that their children can learn.
Citation needed - this seems to disagree, and, more generally, I would expect the ability to learn to go hand in hand with the ability to teach. Anybody whose cat had kittens knows that teaching exists in animals.
From what I've read in Chimpanzee Politics, I got the impression that chimps are pretty good at modeling other chips (better than many other primates), so I wouldn't be ''that'' sure that the relative increase in humans was greater in th...
In their 2011 chapter for the Cambridge Handbook of Intelligence, Stanovich et al. review the evidence suggesting that intelligence and rationality are not the same thing and that rationality is often more important than intelligence. They then lament the fact that there are no standard tests for measuring one's "Rationality Quotient." Then they take a few steps toward such a thing by suggesting some important rationality skills (actively open-minded thinking, fine-grained emotional regulation, tendency to seek information and fully process it, etc.) and rationality 'mindware' (probability theory, scientific process, economic thinking, etc.).
Here are those pages in particular: first a graphic of some important rationality skills and mindware, and then a table of the components of rational thought: rationality components, relevant literature citations, and example word problems that would test for each rationality component.