A commenter wanted to know about racial differences in reaction time. I adapted the following table from Rushton’s book, which originated from data by Richard Lynn:

population (9-Year-old children) sample size progressive matrices iq score simple reaction time in milliseconds complex reaction time in milliseconds odd-man out reaction time in milliseconds
east asians in hong kong 118 113 361 423 787
east asians in japan 444 110 348 433 818
whites in britain 239 100 371 480 898
whites in ireland 317 89 388 485 902
blacks in south africa 350 67 398 489 924
standard deviation 64 67 187

I’m assuming the SD was calculated with reference to the British white population, but I could be wrong since I haven’t read Lynn’s original article yet.

The only thing I find suspicious is the incredibly high IQ scores of the East Asians. My guess is that they took an old IQ test, and the results were published before scientists knew to correct for the Flynn effect. I also don’t know how reliable the reaction time test was because reaction time is such a sensitive measure that if the procedure differed even slightly from one sample to another, the effect could be large.