HN commenters in general seem to be fairly dismissive when discussions about IQ come up. (I imagine it comes from a place of humility, because many people here

HN commenters in general seem to be fairly dismissive when discussions about IQ come up. (I imagine it comes from a place of humility, because many people here know that they personally have high IQs.) I thought I understood what an IQ was (it seems like a simple concept), but that was before a friend started a graduate-level school psychology program. If you want to see how complex it is, start here: https://en.wikipedia.org/wiki/G_factor_%28psychometrics%29 https://en.wikipedia.org/wiki/G_factor_%28psychometrics%29 If you're interested in the math, it's all about this: https://en.wikipedia.org/wiki/Factor_analysis https://en.wikipedia.org/wiki/Factor_analysis In simplified and imprecise terms, your IQ is a statistical construct, i.e. not something that can be observed or measured directly, but an imagined variable that (by definition) correlates with a bunch of things that can be measured. See: https://en.wikipedia.org/wiki/Three_stratum_theory https://en.wikipedia.org/wiki/Three_stratum_theory Popular culture fixates on people with very high IQs, but the real importance of intelligence testing in society is identifying people who qualify for interventions or benefits due to low intelligence, usually IQ < 70 (two standard deviations below the mean). There are literally regulations in some jurisdictions that basically say "If you can produce an IQ score of 69 you qualify for X, Y and Z; if you score a 71 you qualify for nothing." Just saying: IQ is definitely fuzzy, but it's not meaningless or just a measure of how good you are at puzzles. Intelligence testing involves actual science and has real stakes in society.