-The problem is, a lot of the blank-slate-compatible hypotheses for group IQ differences become less compelling when you look into the details. "Maybe the tests are biased", for example, isn't an insurmountable defeater to the entire endeavor of IQ testing—it is _itself_ a falsifiable hypothesis, or can become one if you specify what you mean by "bias" in detail. One idea of what it would mean for a test to be _biased_ is if it's partially measuring something other than what it purports to be measuring: if your test measures a combination of "intelligence" and "submission to the hegemonic cultural dictates of the test-maker", then individuals and groups that submit less to your cultural hegemony are going to score worse, and if you _market_ your test as unbiasedly measuring intelligence, then people who believe your marketing copy will be misled into thinking that those who don't submit are dumber than they really are.
+The problem is, a lot of the blank-slatey environmentally-caused-differences-only hypotheses for group IQ differences become less compelling when you look into the details. "Maybe the tests are biased", for example, isn't an insurmountable defeater to the entire endeavor of IQ testing—it is _itself_ a falsifiable hypothesis, or can become one if you specify what you mean by "bias" in detail. One idea of what it would mean for a test to be _biased_ is if it's partially measuring something other than what it purports to be measuring: if your test measures a _combination_ of "intelligence" and "submission to the hegemonic cultural dictates of the test-maker", then individuals and groups that submit less to your cultural hegemony are going to score worse, and if you _market_ your test as unbiasedly measuring intelligence, then people who believe your marketing copy will be misled into thinking that those who don't submit are dumber than they really are. But if so, and if not all of your individual test questions are _equally_ loaded on intelligence and cultural-hegemony, then the cultural bias should _show up in the statistics_. If some questions are more "fair" and others are relatively more culture-biased, then you would expect the _order of item difficulties_ to differ by culture: the ["item characteristic curve"](/papers/baker-kim-the_item_characteristic_curve.pdf) plotting the probability of getting the biased question "right" as a function of _overall_ test score should differ by culture, with the hegemonic group finding it "easier" and others (answering honestly) finding it "harder". Conversely, if the questions that descriminate most between differently-scoring cultural/ethnic/"racial" groups were the same as the questions that discriminate between younger and older children _within_ each group, that would be the kind of statistical clue you would expect to see if the test was unbiased and the group difference was real. Hypotheses that accept IQ test results as unbiased, but attribute group differences to the environment, also make statistical predictions. Controlling for parental socioeconomic status only cuts the black–white gap by a third.
+
+[TODO: sentence about sources of variation within/between groups based on Jensen]
+
+[TODO: sentence about colorism based on https://www.mdpi.com/2624-8611/1/1/17/htm "Skin color is actually only controlled by a small number of alleles, so if you think societal discrimination on skin color causes IQ differences"]
+
+And so on.
+
+In mentioning these arguments in passing, I'm definitely _not_ trying to provide a comprehensive lit review on the question. (That's [someone else's blog](https://humanvarieties.org/2019/12/22/the-persistence-of-cognitive-inequality-reflections-on-arthur-jensens-not-unreasonable-hypothesis-after-fifty-years/).)