Shamelessly stealing this post from reddit because it's a really cool story:
Context - László Polgár, a Hungarian educational psychologist, conducted an experiment to prove that exceptional talent is developed through intensive education and training, not innate ability. He believed in his theory so strongly that he sought a partner willing to raise children under this philosophy. Polgár wrote to Klára, a Ukrainian teacher, explaining his ideas and proposing marriage as a collaboration in this experiment. Intrigued, Klára agreed, and they married, later raising their three daughters—Susan, Sofia, and Judit—as chess prodigies. From a young age, the girls were immersed in chess and rigorous intellectual training The experiment was a success: all three became world-class chess players, with Judit Polgár widely regarded as the greatest female chess player in history.
- Posted here by /u/heroking4
Your whole baseline assumption in this thread is that most people are raised in an environment where they are likely to reach their full genetic potential. That's an assumption that isn't true in most populations.
If you have a population that has poor childhood nutrition, they won't grow to be as tall as if they had proper access to good food. If you have a heterogenous population where some have access to good nutrition and some don't, then the distribution of heights in that population will be less genetically determined than if they were all equally fed good nutrition.
Or, for another example, we know the number of fingers a person has is coded in their genes. But if you actually go perform a survey of the population to see how many fingers they have, and you collect their genomes, you wouldn't be able to correlate those observed outcomes to genomes, because pretty much everyone who has a number of fingers other than 10 got that way through something environmental (perhaps prenatal development, often an industrial accident or something). So the heritability of the number of fingers is actually close to zero.
Same with sports or fitness: rank the population by how fast they can run 5k, and you'll find out basically nothing about their genetics from those results. The variance in outcomes is utterly dominated by how much they actually run and train, not their genetic potential.
Turning to intelligence, that same phenomenon plays out. Childhood lead exposure, childhood nutrition, access to education (including mentorship and social support for learning), family stability, external stressors (and the accompanying internal changes to one's endocrine system and brain development in high stress environments), all contribute to intelligence. And certain traits that do affect intelligence are less heritable than others (e.g., certain cognitive conditions). All those factors put together in the real world "experiment" of how humans grow up differently mean that even if intelligence were highly heritable in a homogenous environment, the differences in people's environments would still get a wide distribution of outcomes due to non-genetic factors.
No it is specifically not, what are you even talking about? Did you even read anything in my comment? This whole thing is about explaining difference in outcome with near identical environment. This is not about absolute predictions its about potential, which is why i specifically bothered to preface the whole thing with the following.
Nobody in their right mind denies that environment is the most important factor.