Correlation != causation.
Smarter people may create a more educational home life, or push their children better in schools. It may be that intelligence causes better incomes, which leads to better childhood nutrition. It could even be something weirder, such as smarter people being more likely to seek medical care, which leads to healthier children being more able to take advantage of the education which is offered.
I'm referencing studies where all of those things are accounted for. End of story: everyone's the same at the end of the day.
ebola - I was directing that at the conversation in general, not you. Yes, we agree.
My brother and I, and my family in general, are pretty testament to the genetic component of IQ. I know more "geniuses" in my family than the rest of everyone I know combined, and even with wildly different childhoods, my parents, aunts, uncles, and cousins all have very similar intellects. My mom and dad were some of the brightest among their siblings, and my brother and I are some of the brightest among our cousins. My brother and I had a very bizarre childhood with mentally ill abusive parents and a decidedly unusual parental environment in general (i.e. lots of stuff that tends to correlate with poor intellectual outcomes), and although we came out very differently (I'm doing all the "right" things, he's doing all the "wrong" things), we're both still bright in exactly the same ways our parents are. My dad's brain and mine work so similarly it's disturbing sometimes...
That all being said, AGAIN, it's on a bell curve. There's also the Flynn effect and all that.
End of story: there is a genetic component to the transmission of intelligence between generations. Don't read into that. This speaks nothing to the propagation in a given population.
Okay, super fun fact. I googled "genetic difference black white" to find the exact stat on genetic similarity between races, and the first several pages that came up were about race and IQ, even though I mentioned nothing about intelligence in my search... Popular topic, eh? But for reference:
"Human to human total genetic variation is approximately 0.5%. Single-nucleotide polymorphisms (SNPs) are single base-pair DNA differences accounting for 0.1% variation. Of this 0.1% difference, 85% is found within any given population, 7% is found between populations within a continent and only 8% is found on average between the various continental populations. Based on this observation, evolutionary biologist Richard Lewontin has claimed that accurate racial classification of humans is impossible and can have no taxonomic utility. However, this view has been rejected by geneticist A. W. F. Edwards in his paper entitled Human Genetic Diversity: Lewontin's Fallacy (2003). Edwards argues that accurate classification of humans is possible because most of the data that distinguishes populations occurs in correlations between allele frequencies, although these classifications vary depending on a number of criteria, such as sampling strategy, type of locus, distribution of loci around the genome and number of loci. Nonetheless, Witherspoon et al. (2007) demonstrate that
even when accurate classification of human populations is achieved, often individuals classified into different groups are more genetically similar to each other than to members of their own group. This seems to be due to the fact that multi-locus clustering does not take into account the genetic similarities between individuals, and only uses population level traits for comparison. They conclude that accurate classification of individuals drawn from a continuously varying human population may be impossible.
Compared with most other species, the amount of genetic diversity among humans is relatively small. For example, two random chimpanzee are expected to differ by about 1 in 500 DNA base pairs, equivalent to double the diversity amongst humans. This may indicate that chimpanzees have existed as a species much longer than humans.[8]"
And another fun fact: i noticed a striking correlation when I glanced at some "studies." The ones that were trying the hardest to push a particular agenda all make really bold mention of how many pages they are/how long they are. lol