Across the world, there are numerous examples of groups of people that are in conflict. Often, there is no clear reason why these people are fighting other than some arbitrary border or prejudice based on certain cultural traits and rituals or difference in opinion and value. Take Catalonia, for the past decades they are fighting for the independence of Spain. Especially in the last years, the discussion is heating up. They are resulting in rebellions, protests, and contra reactions of the Spanish government. The other example is the difference between democrats and republicans in the US. Often they are aligned opposite of each other and on most points, they think radically different. You could say that this difference in groups is all arbitrary. Some people have been manipulated to follow ideologies that hold influence over them and those are stronger than their own desire for survival-by-cooperation.
Group forming is a fundamental characteristic of human social interaction. Groups create boundaries for who is part of your tribe and who isn’t. An in-group can be formed by any similarity between two or more people and, similarly, and out-group can be formed through any arbitrary distinction.
So how is it possible that seemingly similar groups of people can be so divided? The Robber’s Cave Experiment (1945) conducted by Muzafer Sherif provides a possible explanation for this phenomenon. In the experiment, he takes this question into an artificially created environment. Sherif created a fake summer camp with two groups of boys of about 20 boys each and the first week of the camp they separated the boys so the boys didn’t know of the existence of the other group. The experiment focused on group bonding at this time, creating an identity using names, flags, and multiple in-group activities. As expected, after about a week of activity it brought the boys in the two groups together as a team. In the second stage of the experiment, the researchers introduced the two groups to each other. They added cross-group competition where there could only be one winner and one loser. This competition creates a lot of tension between the group which ultimately lead to vandalism, violence and even physical abuse to the point that the experimenters had to separate the boys. The Robbers cave experiment thus highlights how certain factors can create such prejudices among seemingly equal groups. By creating an identity and add in cross-group competition the prejudices emerged.