- How do we control for self-fulfilling prophecy? I would imagine that having "Member of gifted kids study" will be quite impressive to the gatekeepers at elite universities. Did they add a few dummies to control?
- How do we even measure ability? You'd think the smart kids are smart because they try to learn the things that are tested. It's like testing people for strength. People who've trained are stronger. And they want to be.
- It makes sense that spatial ability is somehow predictive. Nobody ever teaches it, so you're left with whatever nature gave you. Probably like testing someone's toe strength as an indicator of overalll muscle quality (not that I know anything about physiology, it's just that I've never seen anyone at the gym training their toes).
- From what I can tell, it helps an awful lot to have someone nearby who has the skills you're after. Look at the people mentioned. Terence Tao's parents were both highly educated in STEM. Lenhard Ng's dad is a Physics prof. That kind of resource takes you an awfully long way along your path. I mean imagine being able to ask the guy you eat dinner with every night anything from "what is a prime number" to "what's the quantum hall effect". If you don't happen to have a parent, it probably helps to go to a school that is well resourced. There will be teachers around who find time for the kids who show aptitude. I remember being put up a year in math and sent to math contests. I don't think I'd have studied it as much if I hadn't been noticed by the teachers at a young age.
- There's an inherent conflict between society's goals and the gifted. It's a lot more economical to pour money into the mediocre for society. You want to teach everyone to read, write, and a little math. It's cheaper to produce that resource, and it's at the margin you get the most bang for your buck. PhDs cost a fair bit to fund, and like that famouns xkcd, you are only slightly enlarging the world's knowledge. Putting a kid in front of a world authority is expensive.
- It may not be so bad that society doesn't spend money on the gifted (I'd rather call them the more motivated, but...) than the marginals. It's possible that the mass of money needs to be spent making sure everyone can be a little educated, while a rather different effort is made to help the gifted. For instance, what I really, really needed as a kid was other kids who cared. These days that should be easy enough to arrange over the internet.
- There will be a natural experiment occurring soon, right now, about whether it's innate ability or exposure. The proliferation of materials on the internet will create a bunch of kids who are able to learn huge amounts about whatever they're interested in, before they even finish school. When I was a kid, you had to lug your ass to a library to find out what a quaternion was. And it wasn't a specialist library, and there'd be a chapter or something like that. These days there's a flood of information, you just have to type into google. There's so much that if one guy doesn't explain it well, another guy will.