I think that there are characteristics in all humans that don't depend on ethnic background. For instance, having two legs and walking upright, having emotions, having
opposable thumbs. Intelligence is one of these shared human characteristics.
You would have to assume that one race is mentally inferior to another to begin with to determine that race influences intelligence. I just don't see any credible evidence to support that theory.
Does race determine eye color or does it have nothing to do with it?
Does race determine skin color or does it have nothing to do with it?
Does race determine height or does it have nothing to do with it?
All dogs share common characteristics, like having four legs, having emotions, not having opposable thumbs. So why have you determined that you will NEVER own a pit bull?