IQs predict, but much more weakly, how well people will do in terms of jobs and income. Otherwise college professors would be the richest people. More negatively, low IQ scores predict weakly the likelihood of going to jail, using dope, having babies without being married, and generally doing things that are dangerous and not respectable. However the conservatives make this exciting by noting that different population groups have different average IQ scores. The implication is that Blacks are a biological group that is innately inferior to whites in intelligence, and that this causes Black poverty and crime.
Black people have quite a lot of white ancestry, as whites have a good deal of Black.
Different ethnic and class groups have different social psychologies each group's common way of thinking, valuing, and behaving. Some social groups have been faced with great oppression, discrimination, forced poverty and degradation, with few avenues for learning or social rising. Parts not all of these groups respond by rejecting the values of education and by internalizing their oppressors' view of themselves to an extent. Of course this does not prove that these groups are biologically inferior in intellectual ability. Along with weaknesses, their cultures also have great strengths.