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[THREAD] I was asleep last night pretty early, so I did not see the @NickJFuentes Zoom debate, but there were some clips from the debate talking about the science of intelligence (and race) which don't hold up to any actual scrutiny.
1/To be fair to normies, they get most of their information from crap science and media blogs and they have never read an academic paper in their life. They genuinely have no idea statements like "IQ is invalid" and "IQ isn't heritable" have no scientific backing.
2/ For starters, IQ tests are the most validated construct in psychology and even probably the most validated in all of the social sciences. It's impossible to get into all the history and data in a Twitter thread, but we know IQ Q mcorrelates with important life outcomes,...
3/including school success, job success, health, mental health,and longevity.
https://www.sciencedirect.com/science/article/abs/pii/S0160289616302331
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170757/
https://www.gwern.net/docs/iq/2015-strenze.pdf
http://maamodt.asp.radford.edu/PSYC%20651/Huffcutt%20&%20Arthur%20(1994)%20Interview.pdf
https://www.sciencedirect.com/science/article/abs/pii/S0160289616302331
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170757/
https://www.gwern.net/docs/iq/2015-strenze.pdf
http://maamodt.asp.radford.edu/PSYC%20651/Huffcutt%20&%20Arthur%20(1994)%20Interview.pdf
4/
It's highly unlikely all of these correlations could exist by chance. IQ is a good test for general intelligence ("g") and this test correlates with most important life outcomes in a way we would expect if it were measuring intelligence.
It's highly unlikely all of these correlations could exist by chance. IQ is a good test for general intelligence ("g") and this test correlates with most important life outcomes in a way we would expect if it were measuring intelligence.
5/ What is the heritability of IQ? First, let's briefly define heritability. In short, heritability measures what percentage of the *variation* of a trait is due to genetics in a population. Heritability doesn't make sense when looking at a single individual, so you can't say
6/"60 percent of my IQ is genetic" if heritability equals 0.6. Doesn't work that way. It is explaining what percentage of the *variation* between individuals is genetic.Heritability also varies depending on environment,i.e. heritability is likely much higher in the US than Africa
7/Research reviews suggest the heritability of IQ in the US for the general population is anywhere between 50 and 70%. Almost no one who publishes in this field anymore thinks IQ is anywhere near 0% heritable - it is a debate over how heritable it is.
http://moemesto.ru/rorschach_club/file/6314265/182%20bouchard%202003.pdf
http://moemesto.ru/rorschach_club/file/6314265/182%20bouchard%202003.pdf
8/Since heritability can vary depending on environment, maybe heritability is lower among blacks than it is among whites. Nope. In the U.S., the heritability of intelligence does not vary between races. https://www.sciencedirect.com/science/article/pii/S0160289619301904
9/Another important aspect of this debate is known as the Wilson effect. The review of heritability above includes papers whose samples are mostly children, which is problematic because the Wilson effect states heritability increases with age. This intuitively makes sense:
10/genes express themselves more over time (many of us know people who were blonde as children but have brown hair as adults). Life experiences also accumulate over time, but for intelligence the former effect seems to be more salient.
11/By adulthood, intelligence is 80-85% heritable, whereas in childhood it is closer to 40%. [ https://www.ncbi.nlm.nih.gov/pubmed/23919982 ] This brings us to an important piece of evidence regarding the genetic component of racial intelligence gaps: the gaps increase with age! https://www.brookings.edu/wp-content/uploads/2016/07/20060619_response.pdf
12/People on the stream argued racial gaps existed but there was no proof it was genetic; as noted in the last tweet, there is evidence it is genetic, and the increasing size of the gap with age is one of them. imo, the strongest piece of evidence is the gaps in relation to "g"
13/IQ tests are comprised of multiple sub tests (say, vocab, block assembly, digit span, etc). Each of these subtests are more or less "g loaded"; that is, some subtests measure g more than others. As a result, some subtests are more heritable than others. [...]
14/ The most heritable and g-loaded subtests are also the subtests which return the largest racial differences, exactly what hereditarians would predict. https://humanvarieties.org/2013/07/05/hollow-flynn-effect-in-two-developing-countries-and-a-further-test-of-the-debatable-black-white-genetic-differences/
https://www1.udel.edu/educ/gottfredson/30years/Rushton-Jensen30years.pdf
https://www1.udel.edu/educ/gottfredson/30years/Rushton-Jensen30years.pdf
15/Of course, the fact heritability is 80% heritable in adulthood also counts as evidence, albeit indirectly. Yes, yes, Lewontin's garden can be true, but it does give us a default hypothesis which we should rely upon in the absence of evidence.
16/How can environmentalists explain the persistence of racial IQ gaps in totally different countries with different histories, cultures, and economic situations? This totally aligns with hereditarianism, not so much for the reverse. …https://lesacreduprintemps19.files.wordpress.com/2012/08/intelligence-a-unifying-construct-for-the-social-sciences-richard-lynn-and-tatu-vanhanen.pdf
17/And what about brain size? While it is often claimed linking brain size w/ intelligence is pseudoscience, brain size does, in fact, moderately correlate with intelligence.
https://www.ncbi.nlm.nih.gov/pubmed/26449760
http://www.people.vcu.edu/~mamcdani/Big-Brained article.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668913/
https://www.ncbi.nlm.nih.gov/pubmed/26449760
http://www.people.vcu.edu/~mamcdani/Big-Brained article.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668913/
18/And, well... brain size varies by race. We know this from MRIs [ https://www.cambridge.org/core/journals/psychological-medicine/article/volumetric-mri-measurements-in-bipolars-compared-with-schizophrenics-and-healthy-controls/D52FA3A8908C557E9FA88C7B358A7300; http://philipperushton.net/wp-content/uploads/2015/02/iq-race-brain-size-kamin-omari-rushton-personality-individual-differences-2000.pdf], autopsies [ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668913/], and external head size [ http://philipperushton.net/wp-content/uploads/2015/02/iq-brain-size-rushton-intelligence-1992.pdf].
19/ What causes these gaps? Environmentalists have argues these gaps are due to environmental factors, like nutrition. Further, for autopsy studies, things like age of death could bias the results. Probably not. Racial group differences in brain size seem to be related w/...
20/ multiple musculoskeletal traits which are associated with brain size (like birth canal size; you need bigger hips if the kid has a larger brain). This suggests the average bodies of diff. races evolved around brain size - which suggests the brain size diffs. are natural.
21/ see: http://philipperushton.net/wp-content/uploads/2015/02/Brain-Size-IQ-and-Racial-Group-Differences-Evidence-From-Musculoskeletal-Traits-2003-by-John-Philippe-Rushton-Elizabeth-W.-Rushton.pdf
And, finally, we get to the last objection: find the genes! Unfortunately for environmentalists, we are, in fact, finding the genes. Lasker et al. (2019)'s polygenetic score data is consistent w/ race IQ gaps being 50-70% heritable.
And, finally, we get to the last objection: find the genes! Unfortunately for environmentalists, we are, in fact, finding the genes. Lasker et al. (2019)'s polygenetic score data is consistent w/ race IQ gaps being 50-70% heritable.
22/Lasker: https://www.mdpi.com/2624-8611/1/1/34/htm
This association has also been found on a national level: countries with a higher frequency of intelligence related genes tended to score higher on IQ tests. https://www.ulsterinstitute.org/intellofnations.html
This association has also been found on a national level: countries with a higher frequency of intelligence related genes tended to score higher on IQ tests. https://www.ulsterinstitute.org/intellofnations.html
23/Piffer (2019) found a correlation between a countries' polygenetic score and national IQ of 0.89. https://www.mdpi.com/2624-8611/1/1/5the
Piffer (2015) looked at 9 SNPs, and national IQ correlated w/ his polygenetic score at 0.91.
Piffer (2015) looked at 9 SNPs, and national IQ correlated w/ his polygenetic score at 0.91.
He also found the SNPs positively associated w/ IQ were the least common among blacks (36%), followed by 53% for whites and 60% for Asians. In other words, exactly what hereditarians would predict. While Piffer (2015) was only looking at a few SNPs, we must ask: why do all 9...
SNPs match up with race exactly how hereditarians would predict? That likely wouldn’t happen by chance.
None of what I said is extreme; the majority of researchers think genes play some role in the racial IQ gaps [ https://www.sciencedirect.com/science/article/pii/S0160289619301886/]. This is all in line with what’s being published and what experts believe. IQ is real, racial IQ gaps are real, and the gaps are partly heritable
