Humans are social animals, programmed to form groups, but why do we treat some groups favorably and dismiss others? This is an “us versus them” mentality that not only divides society but has historically led to genocide.

So what causes the “us and them” mentality and how does this thinking trap divide society?

I believe there are three processes that lead to an “us and them” mentality:

development
I learned to survive
identification
But before I discuss these processes, what exactly is an “us versus them” mentality, and are we all guilty of it?

Us vs. them mentality definition
It is a way of thinking that favors individuals in your social, political, or other group and disapproves of those who belong to a different group.

Have you ever supported a soccer team, voted for a political party, or proudly flown your national flag on your property? These are all examples of “us versus them” thinking. You choose one team, whether it’s your favorite team or your country, and you feel comfortable in your group and nervous about the other.

But there is more between us and them than simply choosing sides. Now that you’re in a particular group, you can make certain assumptions about the types of people who are also in your group. This is your group.

If you are a member of a political group, you will automatically know, without asking, that other members of that group will share your ideas and beliefs. They will think the same way you do and want the same things you do.

You can also make these kind of assumptions about other political groups. These are outgroups. You can make judgments about what kind of individuals make up this other political group.

And there’s more. We learn to think positively about our in-groups and look down on out-groups.

So why do we form groups in the first place?

Groups and us against them
development
Why did humans become social animals? It’s all about evolution. In order for our ancestors to survive, they had to learn to trust and work with other humans.

Early humans formed groups and began to cooperate with each other. They have learned that there is a greater chance of survival in groups. But human sociability is not just a learned behavior, it is deeply rooted in our brains.

You may have heard of the amygdala, which is the most primitive part of our brain. The amygdala controls the fight-or-flight response and is responsible for generating fear. We are afraid of the unknown because we do not know if it poses a danger to ourselves.

On the other hand, it is a mesolimbic system. This is an area of the brain associated with reward and feelings of pleasure. The mesolimbic pathway transports dopamine. This is triggered not just in response to something pleasurable but to all the things that help us survive, such as trust and familiarity.

So we are forced to distrust what we do not know and to feel joy about the things we do know. The amygdala produces fear when we encounter the unknown, and the mesolimbic system produces pleasure when we encounter the familiar.

In addition to having brains that fear the unknown and delight in the familiar, our brains have adapted to our environments in another way. We categorize and group things together to make it easier to navigate through our lives.

When we categorize things, we take mental shortcuts. We use labels to identify and group people. As a result, it is easier for us to “know” something about these out-groups.

Once we have categorized and grouped people, we then join a group of our own. Humans are a tribal species. We are attracted to those who we feel are similar to us. The entire time we do this, our brains reward us with dopamine.

The problem is that by categorizing people into groups, we exclude people, especially if resources are an issue.

For example, we often see headlines in newspapers about immigrants taking our jobs or homes, or world leaders calling immigrants criminals and rapists. We choose sides and do not forget that our side is always the best.

Us Against Them Mental Studies

Two well-known studies highlight this “us versus them” mentality.

Brown eyes study of blue eyes, Eliot, 1968

Jane Elliott taught third graders in the small, all-white town of Riceville, Iowa. The day after Martin Luther King Jr.’s assassination, her class came to school, visibly upset by the news. They couldn’t understand why the “hero of the month” was killed.

Elliot knew that these innocent children in this small town had no concept of racism or discrimination, so she decided to experiment.

I divided the class into two groups; Blue-eyed people and brown-eyed people. On the first day, blue-eyed children were praised, given privileges, and treated as if they were superior. In contrast, children with brown eyes had to wear collars around their necks, and were criticized, ridiculed, and made to feel inferior.

Then on the second day the roles were reversed. Blue-eyed children were ridiculed and brown-eyed children were praised. Elliot watched the two groups and was amazed at what happened and how quickly it happened.

“I’ve watched wonderful, helpful, wonderful, thoughtful kids turn into bad, nasty, special third graders in the space of fifteen minutes.” -Jane Elliott

Before the experiment, all the children were kind and tolerant. However, during the two days, the kids chosen as bosses became mean and started discriminating against their classmates. These children who were rated as inferior began to act as if they were inferior students, and even their grades suffered.

Remember, these were nice, tolerant kids who had named Martin Luther King Jr. Hero of the Month just a few weeks earlier.

Thieves’ Cave Experiment, Sharif, 1954

Social psychologist Muzaffar Sharif wanted to explore conflict and cooperation between groups, especially when groups compete for limited resources.

Sharif selected 22 twelve-year-old boys and then sent them on a camping trip in Robber’s Cave State Park, Oklahoma. None of the boys knew each other.

Before leaving, the boys were randomly divided into two groups of eleven. Neither group knew about the other group. They were sent by bus separately, and upon arriving at the camp they were separated from the other group.

Over the next few days, each group participated in team building exercises, all designed to build a strong group dynamic. This included choosing the names of the groups – Eagles and Rattles, designing the flags, and choosing the leaders.

After the first week, the groups met each other. This was the stage of conflict where the two groups had to compete for prizes. Situations are designed where one group gains an advantage over the other group.

Tensions escalated between the two groups, starting with verbal insults. However, as rivalries and conflicts continued, verbal taunts took on a more physical nature. The boys became so aggressive that they had to be separated.

When talking about their own group, the boys were overly positive and exaggerated the other group’s failures.

Again, it is important to remember that these were all normal boys who had not met other boys and had no history of violence or aggression.