|Copyright Masaya. Source|
Grouping occurs when similarities or differences are noted.
One study showed that people are more likely to go sit next to someone with the same haircolour as them if they come into a room full of people looking for a seat.
The human nervous system works by appraising things and then deciding if they are a threat or not (or at least, one theory suggests that). When looking at something, you automatically categorise it as either the same as you or different. First, human or not human. If human, then it is categorised as either the same or different. If you look at survival way back when, people different from you will probably be out to kill you, since they will likely be part of a different tribe.
There was a study done where a class of children were treated differently according to their eye colour. The blue eyes were often rewarded while the rest were treated worse. The children were under 10 years. Very soon, the kids with the different coloured eyes formed a group and those with the blue eyes grouped and already formed a strong Us vs Them mindset.
Even children as young as that form groups according to circumstances. There is a natural tendency to treat people who differ from you differently. Ergo, the birth of racism.
In the end, there are two main things that can happen within a community if two different cultures are mixed together. Either the minority will be consumed and converted by the majority, or the two cultures will essentially segregate and deal mainly with their own kind (okay, three, the two cultures can combine and form a new culture, which is probably the best solution).
How many times are you grouping every day? How many times do you classify someone as part of “Us” or a part of “Them” without realising it?