So maybe humans are naturally inclined to develop an appreciation for harmony based on an overtone series, but nurture determines which overtone series we are most exposed to?

Music appreciation has to happen within culture as well as physics. You can probably think of several musical genres that you don't like--but I would be astonished to hear of even a single genre that some genetic group liked, and others couldn't learn to enjoy.

When we encounter visual situations that rarely arose throughout the period of human evolution, our instincts can lead us to interpretations that conflict with reality; this is an evolutionary explanation of optical illusions. Similarly, when we encounter moral situations that rarely arose throughout the period of human evolution, our instincts may lead us to decisions that are hard to reconcile with what we regard as moral behavior.

When I see an optical illusion -- like Wile E. Coyote trying to run into a tunnel painted onto a cliff face -- my visual cortex is fooled, even if I know it's an illusion, and even if I know the principle behind the illusion. But the moral equivalent doesn't persist: once you correct your knowledge or your reasoning, nothing is left of your indignation based on faulty reasoning or incorrect evidence.

It appears that moral "biases" can be "overcome", but visual "biases" can only be worked around. I think that's evidence in favor of an "nature" explanation for optical illusions and a "nurture" explanation for moral biases.