collapse of the old society

Yes, we often refer it it as a heuristic because it's a mental shortcut. There are ways to counter act it, such as described in the contact hypothesis (e.g. get to know a group by having interdependence with an out group). Having a shared category with someone can also help, like being part of the same team, organization, etc.

For example, a study looked at the response rate at a sporting event when researchers approached people to participate; a black researcher and a white researcher. Under control conditions, the black researcher had a harder time getting white participants to help and to a lesser extent, vica versa. However, when they wore the same team hat, participation was close to even. The idea is, the hat showed that they belonged to the same in-group, reducting or eliminating the hesitation of participation.

I often forget author names but I can probably dig it up later. There's a lot of studies about this in social psychology since there's a general interest in getting people to stop being so damn racist, haha.