Different groups of humans have different cultural mindsets in terms of education, values, hard work, etc. You don't need a sociologist to tell you this, just observe everyday life if you're living in a multi-racial and multi-cultural society. Hell, just take a look at the various nations and their cultural values placed on this. Of course as someone said, uttering these in public can bring dire consequences and one will be labeled something they're not. But those peer reviewed academic journals I have read when doing reports when I was still in school have all confirmed this. While some political correctness is good, an over abundance of it stifles any reasonable solution or discussion to the problem for fear of being labeled a bigot for pointing out the obvious reasons. It is what it is.