It has been shown that if a modern human is not taught human language, and has void or very limited human contact/interaction (except for feeding) he will fail to speak, mature, and act more or less barbaric. Nurture has a lot to do with behavior considered civilized or "human". "Evolved", "higher" brains have little to do with what makes us human. Whatever natural "human" inclinations or potential we may be born with fail to develop if not nurtured.
But the exact same thing can be said of any primate, ape, monkey. In fact, the same can be said of most, if not all, mammals.
So you ask where did the first human get the knowledge?
But I'll ask where did the first monkey get it, or dolphin, or bat get that very same knowledge?
Why stop at humans when many, many more species down the line show this same behavior?
However, if you understood common ancestry then you would see how these traits emerged and came to be present in modern mammals, which obviously includes humans.
- Oni