This question is as old as the stars, except we replace "an AI with no basis for how humans think" with "an infant child with no basis for how humans think." And, to be perfectly honest, most children leave the lab far before they can interact with people without seeming strange, but that's okay.
Accordingly, the answers are also as old as time itself. Religion is a popular one, teaching ethics and morals. Logic is a popular one, teaching reason. In the east, The Present is a popular one, teaching one to live in the moment. Science is a popular one, teaching experimentation.
Myself, I find the most valuable of all lessons for teaching us what it is to be human are paradoxical. It's a natural consequence of trying to capture something important in language. In religions, we find the paradoxes in how we are taught to have faith without becoming gullible. In logic we find the paradox of language seeking to fully describe something which it can prove can never be fully described. In the present, we find the paradox of living today like it's your last, yet being ready to greet the sun as it rises tomorrow. In science, we find the paradox of empiricism, that maybe all we have ever come to learn is but shadows upon the Cave wall yet we must act on what we have seen none the less.
There are many paradoxes which we use as diving boards to start our plunge into what is humanity. My personal favorite is radical skepticism: the idea that the truth value of anything can never be known. It forces one to always be aware of unintended side effects and always be aware of the unknown unknowns. And yet, when applied to itself, one must be skeptical of radical skepticism. It forces one to consider the possibility that there might indeed by a thing whose truth value can be known, so one can never simply rest on the knowledge that knowledge can never be attained.
But that paradox is just one of many. Pick your favorite and see where it leads your AI.
Buddha told a parable in sutra:
A man traveling across a field encountered a tiger. He fled, the tiger after him. Coming to a precipice, he caught hold of the root of a wild vine and swung himself down over the edge. The tiger sniffed at him from above. Trembling, the man looked down to where, far below, another tiger was waiting to eat him. Only the vine sustained him.
Two mice, one white and one black, little by little started to gnaw away the vine. The man saw a luscious strawberry near him. Grasping the vine with one hand, he plucked the strawberry with the other. How sweet it tasted!