I did dance around the lifestyle point a bit, for this reason. I've never seen a study on "we took otherwise-healthy people with bad habits and got them to eat,

I did dance around the lifestyle point a bit, for this reason. I've never seen a study on "we took otherwise-healthy people with bad habits and got them to eat, sleep, and exercise better", but I'd have higher hopes for that boosting healthy-adult IQ than literally anything else. And I agree on the ambiguity around 'innate ability'. One could argue that general health is 'subtractive', that bad sleep/diet/exercise are drawing down potential that would exist otherwise. But that's far less clear-cut than something like "only works in dementia patients" or "only helps with Korsakoff Syndrome". I think there's something to it - lifting heavier weights and sleeping more are not unbounded sources of improvement - but I think it's also kind of a copout. If those things operate on a continuum, and people we consider "healthy adults" can still see benefits from them, that's what we wanted to find.