It’s pretty much set by the time you are an adult, and we know of nothing besides iodine deficiency that has a meaningful impact on it in the context of a baseline person in modern society.
This is not really true, AFAICT. There are so many health conditions that result in recognizable cognitive impairment that I see no reason to assume that the “baseline person in modern society” is effectively maximizing her realized IQ. Even something as common as major depressive disorder can impact cognition in ways that will make people measurably less effective at work. And let’s not forget more permanent things like eating too many lead flakes as a kid, which can still have an impact on the “baseline person” long after lead paint has fallen out of use.
You are correct, there are things that can negatively impact someone’s IQ. With respect to maximizing, I think the fact that people have been trying for decades to find something that reliably increases IQ, and everything leads to a dead-end means that we are pretty close to what’s achievable without revolutionary new technology. Maybe you aren’t at 100% of what’s achievable, but you’re probably at 95% (and of course percentages don’t really have any meaning here because there is no metric which grounds IQ in absolute terms).
This is not really true, AFAICT. There are so many health conditions that result in recognizable cognitive impairment that I see no reason to assume that the “baseline person in modern society” is effectively maximizing her realized IQ. Even something as common as major depressive disorder can impact cognition in ways that will make people measurably less effective at work. And let’s not forget more permanent things like eating too many lead flakes as a kid, which can still have an impact on the “baseline person” long after lead paint has fallen out of use.
You are correct, there are things that can negatively impact someone’s IQ. With respect to maximizing, I think the fact that people have been trying for decades to find something that reliably increases IQ, and everything leads to a dead-end means that we are pretty close to what’s achievable without revolutionary new technology. Maybe you aren’t at 100% of what’s achievable, but you’re probably at 95% (and of course percentages don’t really have any meaning here because there is no metric which grounds IQ in absolute terms).