@Lex fridman / Richard : have you considered the argument of the GENETIC  effect of NURAUL DIVERSITY( autism, adhd, dyslexia, dyspraxia etc) AND/or  DYSLEXIC BASED LEARNING DISABILITIES AND ITS EFFECT ON IQ METRIC OUTCOMES!  This could account for all of the population's differences, as studies do indicate 1) prevalence  and occurrence of dyslexia and neural diversity is higher in  (at least in NZ) indigonos populations, not sure if this is same for other minorities . 2)neural diverse individuals (dyslexic's) often  score lower( to my knowledge) in IQ tests , and have the highest variability  and increase the most over time.3) this could explain the "flynn effect"as dyslexia is picked up sooner and more friendly to dyslexic education modes , slowly increasing  the correct measure of those that are nurul diverse . IE: that the IQ is more correctly measured. .4) part of this is that neural diverse individuals have to process more information than a verbal liner thinker. Therefore their brain has to work harder to come to the same conclusion( however more concrete as a concept  as a rule in the neural diverse) thus skewing the results .   IQ test  5) as dyslexia/nurul diversity has been measured  according to some up to 20% of the population and   is found across all IQ ranges and is also heavily genetically linked , one could assume it accounts for all effects seen ?  6) lex you paint pictures in my head and your SAT mismatch  could be indicative of a dyslexic thinker ( not the learn disability , but the ability of playing with pictures in your head) .7) now I have a Bsc psychology and geology and are a higher functioning corrected dyslexic.  So I'm never going to spell perfect , however , I can see things and create pictures and play with them in my head , HOw can you possibly measure this ability and is this an intelligence??