I often use the metaphor that rationality is the martial art of mind.  You don't need huge, bulging muscles to learn martial arts - there's a tendency toward more athletic people being more likely to learn martial arts, but that may be a matter of enjoyment as much as anything else.  Some human beings are faster or stronger than others; but a martial art does not train the variance between humans.  A martial art just trains your muscles - if you have the human-universal complex machinery of a hand, with tendons and muscles in the appropriate places, then you can learn to make a fist.

How can you train a variance?  What does it mean to train +2 standard deviations of muscle?  It's equally unclear what it would mean to train an IQ of 132.

But if you have a brain, with cortical and subcortical areas in the appropriate places, you might be able to learn to use it properly.  If you're a fast learner, you might learn faster - but the art of rationality isn't about that; it's about training brain machinery we all have in common.