Small children typically ignore race, but there does seem to be (at the very least) a cultural tendency towards racism as people move into adulthood. There is a good book about it called "Why are all the black kids sitting together in the cafeteria?" https://www.amazon.com/Black-Kids-Sitting-Together-Cafeteria...

People's characters need to be formed, I would at least argue, to overcome a normal tendency to be uncomfortable with difference.