I'm actually skeptical of "natural ability," and I find it... a cop-out to ascribe learning rates to it. I think presence of mind matters. All practice is good, but some practice is better than others. People who are continually conscious of their performance, and who actively try to figure out how to improve will probably learn faster than someone who practices passively and hopes to improve "by accident."
No one's figured out a grand unified theory of Physics either but they still have a lot more useful conclusions and solid research than we do on ability.
