[ericd]

I think there's probably an evolutionary origin - genes that compel their owners to look out for others with the same genes over those who are unlikely to share genes were likely to be more successful overall in our more violent past. Now selection favors those who are able to work well with others of all races, so perhaps it's fading.

[zootar]

Why do you think selection favors "those who are able to work well with others of all races"?

[ericd]

Because being a racist nowadays tends to cause one to be marginalized by others, and not be as successful. Today's business environment favors the person who can work well with anyone.

[zootar]

Today's business environment does not exert any evolutionary pressure on the human species.