I think this is well understood so I don’t know why anyone would ask it. However:
HERE IS THE CORRECT ANSWER
The categorization of people into groups of ethnicities is as old as the written record. People are referred to by the color of their skin and the egyptians who were an advanced people for many centuries were diligent in their depiction of the races.
Greeks and romans categorized groups of people by region and skin tone and temperament. And the romans identified that personality traits were driven by geography and climate.
16th century, the ‘shrinking of the world’ due to the Age of Sail led to civilizational and ethnic categorizations.
By the mid 19th century (1800’s) with the advent of Darwin’s research in particular, people both recognized that most ethnic groups could be categorized by regions of the world.
The study of evolution made it rather obvious that we developed regional characteristics just as did all other animals.
The success of the early eugenics movement, but the retaliation against the nazi use of eugenics led to postwar suppression of research, and pseudoscientific denialism of racial differences.
The development of genetic studies has led to the restoration of research and the data is updated monthly with new findings. The most recent work with the most accessible data came out this year (2018) although I don’t think is available in paperback form yet. (“Who we are and how we got here” by David Reich). He tries to soft pedal against the race deniers, but the data is pretty solid now.
The race-deniers have produced popular pseudoscience and been proven false. Those include Stephen j Gould (The Mismeasure of Man), and Richard Lewontin (“racial groups are more different internally than externally”) which is also false – and hard to believe anyone would even say such a thing. It’s so false that the profession has a name for it: “Lewontin’s Fallacy”.
However it is better to take away that each group produced excellences given their geography, climate, regional competitors, and degree of development.
And that the primary difference between the races that cuases conflict (proximity creates hostility) is the vast difference in the size of the lower classes. IQ is the most accurate measure in psychology but when we average IQ we are really saying who has the smallest underclass and the biggers upper class? That’s what IQ by Race, Subrace, and Tribe means.
So it is not so much that conflict is just racial, it’s that because the sizes of white, japanese, korean, and han underclasses are fairly small as a percentage of the population (and european jews have almost eliminated theirs), while the rest of the world tends to have much larger underclasses (from less hostile climates and less forced organized individual farms).
So the problem is that our cultures are incompatible because cultures fill the needs of the median of the distribution – they must. If the eugenicists were successful and we did not have such a population explosion of the lower classes, then within a century the differences between the races would be merely trivial. But the fact that they are substantial because of the differences in the sizes of the underclasses and the political needs of those underclasses, the world remains a racially conflicted place.
The east asians and indians are the most racist so far, with whites the least – which is just the opposite of what you’d think.
Progressive Race, Inequality, and IQ Deniers vs Conservative Global Warming Deniers. Both deniers are trying to satisfy political ends. Truth is painful.