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Many people seem to think there’s a perfect correlation between IQ and academic achievements. So for example, if you achieve some great academic accomplishment, you are declared brilliant in perpetuity and no amount of evidence to the contrary can rob you of the title. So you often hear people make comments like “there’s no correlation between IQ and money; I know a PhD who’s on welfare” or “there’s no correlation between IQ and brain size; that famous math professor has a brain the size of an apple. Do your research!” Never once does it occur to people that the PhD welfare recipient and the apple-brained math professor, while probably both intelligent, are significantly less intelligent than normal PhDs and math professors.

Ted Kaczynski is a good example of why a more holistic view is tenable. Ted Kaczynski was clearly spectacularly accomplished academically; one of the youngest Harvard educated STEM professors in America…I’ve previously estimated that the average professor has an IQ around 130. STEM professors would probably be closer to 140. Precocious Harvard educated STEM professors should be around 150. And yet, Kaczynski ended up dirt poor, struggling to live off the land like a homeless man with no running water or electricity.

Now many people would say “obviously there’s no correlation between stratospheric IQ and money, since Kaczynski was clearly above IQ 150 and lived like a homeless man.” But Kaczynski’s IQ wasn’t anywhere near 150, and that’s the point. Kaczynski, is actually an excellent example of just how robust the IQ income correlation really is, because his IQ is not what you’d expect from the typical precocious Harvard educated STEM professor, his IQ is what you’d expect from a homeless Harvard educated former STEM professor.

Let’s say there are 600,000 homeless in America at any given time, and that Kaczynski was the most academically accomplished homeless type person in America. That would make Kaczynski about 4.7 standard deviations (SD) above the homeless mean. The correlation between IQ and academic accomplishments is about 0.65. One might expect it to be smaller in a restricted sample like the homeless, but the homeless appear to be a little more cognitively variable than the general population so perhaps not. Thus Kaczynski’s IQ should 4.7 SD (0.65) = 3.1 SD above the homeless mean. A recent study found that the WASI full-scale IQ distribution of the homeless has a mean of 84.3 and an SD of 15.7. The WASI was published in 1999, and the study was published in 2011, so we should probably subtract 3.6 points for old norms which expire at a rate of 0.3 points a year, so let’s say the homeless have a mean IQ of 81 (SD 15.7). This mean may be further inflated by the fact that the WASI was normed on the U.S. population, not on an exclusively Nordic ancestry population (as per the current convention in peer reviewed IQ articles) so for simplicity, let’s just say the homeless have a mean IQ of about 80 (SD 15.7), which makes Kaczynski’s expected IQ (3.1 SD above the homeless mean):

3.1 SD(15.7) + 80 = 129

So the most academically accomplished homeless type person in America should have an IQ around 130. As I previously discussed, Kaczynski scored a full-scale IQ of 136 on the WAIS-R, but the norms were about 15 year old at the time he was tested, making his actual IQ 132. Subtract another couple points for the fact that the WAIS-R was normed on the U.S. population, and he would be hovering around the 130 mark, exactly as simple regression would predict for a homeless Harvard educated former STEM professor, and much lower than expected for a typical precocious Harvard educated former STEM professor.

So instead of Kaczynski being an example of IQ having no, or even negative correlation with money among the brilliant or hyper-educated, he’s an example of how financial success provides useful independent information about a person’s IQ, even when they’re a precocious Harvard educated former STEM professor. This demonstrates that IQ tests really do measure intelligence, and not just narrow book smarts, because people who have spectacular book smarts, but lack the street smarts to adapt to the real world have much lower IQ’s than those who are stars in both school and life.

Some might object that Kaczynski was poor by choice, as an ideological statement, and that such adherence to principle, may demonstrate extraordinary brilliance. But the fact that money and IQ are correlated is just a statistic, and statistics don’t ask how or why. One could argue that given the endless benefits of money in modern society, choosing to be poor, when you have the option of being rich, shows even less intelligence than being unable to make money despite being hyper-motivated. Though I’m not sure I’d go that far.