Prison IQ is a very different distribution. As I recall, the top 2% IQ of the general population makes up something like 20% of the prison population. You also have quite a few at the other end.
The gifted are more over represented in prison then black males, however, most of those gifted are themselves minorities.
I’ll have to see some evidence on that, in my search it’s basically a normal bell curve shifted 8 pts down. The idea that 130+ IQ individuals make up 1/5th of the prison population does not pass the sniff test, that would be a crazy statistical aberration. In my search I found reports that 130+ IQ individuals only represent less than 0.4% of the prison population.
Roughly yes, it is declining. The Flynn effect was just smart people having kids later which has now normalized and reversed (with smart people having fewer kids).
The gifted are more over represented in prison then black males, however, most of those gifted are themselves minorities.