The thing is, if you take the species dogs, pigs, horses, apes, and humans, then you can clearly put them somewhere on a scale regarding their ability to learn

The thing is, if you take the species dogs, pigs, horses, apes, and humans, then you can clearly put them somewhere on a scale regarding their ability to learn or understand (a) simple language (b) complex language, (c) simple math (d) advanced math. There might be some edge cases, but an average human will be better at any other species no matter how hard you try. There is a very hard species boundary, so it must be something that is giving to the offsprings. If you further accept that the ability to learn advanced math does not fall from the sky and we somehow descended from an ancestor that did not have this ability, then the only way we got here is that (something that correlates to) this ability was heavily selected for in the past. And you need some kind of continuum (it can also be multi-dimensional) where you can gradually converge to. I don't think this is something that spontaneously emerged. If you accept all this, then the same things will likely still play a role within current humans.