Not quite a Jane Austen title, I know, but this is something I have found very fascinating for years.
Human beings seem to have a natural “love of their own.” Call it prejudice, if you want, but the truth seems to be that it is both deeply human and at the same time, superficial.
But let’s get to the story!

PLANET OF THE APES, Charlton Heston, Linda Harrison, Kim Hunter, Roddy McDowall, 1968, Tm & Copyright (c) 20th Century Fox Film Corp. All rights reserved.
During the filming of Planet of the Apes in 1967, Charlton Heston noted “an instinctive segregation on the set. Not only would the apes eat together, but the chimpanzees ate with the chimpanzees, the gorillas ate with the gorillas, the orangutans ate with the orangutans, and the humans would eat off by themselves. It was quite spooky.”
James Franciscus noticed the same thing filming Beneath the Planet of the Apes in 1969. “During lunch I looked up and realized, ‘My God, here is the universe,’ because at one table were all the orangutans eating, at another table were the apes, and at another table were the humans. The orangutan characters would not eat or mix with the ape characters, and the humans wouldn’t sit down and eat with any one of them.
“I remember saying, ‘Look around — do you realize what’s happening here? This is a little isolated microcosm of probably what’s bugging the whole world. Call it prejudice or whatever you want to call it. Whatever’s different is to be shunned or it’s frightening or so forth.’ Nobody was intermingling, even though they were all humans underneath the masks. The masks were enough to bring out our own little genetic natures of fear and prejudice. It was startling.”
(From Joe Russo and Larry Landsman, Planet of the Apes Revisited, 2001.)
What is so interesting about this (to me) is that the actors self-segregated based entirely on their costumes, their outward appearance. It made no difference if the actor was black, white, or asian; what seemed to be the sole determining factor (for the duration of filming) was whether he or she was chimpanzee, orangutan, gorilla, or human.
On the one hand, this seems like bad news: it suggests that a certain level of prejudice against people who “aren’t like us” in an obvious visual way will always be a part of human nature. I’m certain it is the sort of thing that can be overcome with practice, but it seems to be our default state.
On the other hand, it strikes me as good news: it seems to show that in most cases racial prejudice is an incredibly superficial thing, that it is literally all surface, and that the greater part of this kind of behavior is not rooted in any deep antipathy or hatred of other races.
I suspect this common tendency is part of human nature, and we should certainly be aware of it—but that also means not making more of it than it is. It should caution us about labelling every kind of tendency towards self-segregation as “racism”—assuming that word carries connotations of racial hatred or prejudice.