Es gibt wenige Dinge, die so einfach sind, wie Menschen auseinanderzudivideren

IN MID-JULY 1973, one of the world's leading social psychologists walked through the woods of Middle Grove, New York, searching for the ideal location to start a forest fire.

While many of his contemporaries were conducting bland research on lab rats, Muzafer Sherif yearned to understand how human identities shape violent conflict.

Having grown up amid the ancient rivalry between Turks and Armenians, Sherif wanted to know how groups of people can develop intractable differences, even when they are very similar.

Sherif planned to start a fire as part of an unusual study he was planning in this sleepy, forested town in upstate New York.

With a modest grant from the Rockefeller Foundation, Sherif had created a fictitious summer camp and invited forty eleven-year-old boys to attend.

The boys had been selected to be as similar to each other as possible: they were all White and Protestant, and they were about the same age with no abnormal psychological traits.

None of the boys had known each other before the experiment.

Sherif's plan was to allow the boys to socialize and make friends with each other, but then randomly assign them to teams that would compete in a series of contests.

Once the boys had been arbitrarily assigned to be "Pythons" or "Panthers," Sherif predicted, the mere existence of a collective identity would lead them to develop animosity toward each other.

The experiment was designed to illustrate how humans' intrinsic need for belonging could produce the type of tragic intergroup hatred that Sherif had witnessed as a child.

But Sherif was wrong.

Despite becoming Pythons and Panthers, the boys continued to play together amicably—mostly ignoring their assigned identities.

In a hasty attempt to save the experiment that he spent years planning, Sherif instructed two research assistants to sneak into the summer campers' tents to steal some of their possessions.

But Sherif's attempt to goad the boys into conflict also failed.

The boys calmly discussed the situation, swore to each other that they were innocent, and sensibly concluded that the camp's laundry service had lost the clothing items that had been stolen.

When the campers later began to cast suspicion on their "camp counselors" (the researchers), Sherif—who had been drinking—pulled his two research assistants into the woods and began excoriating them.

When he raised his fist as if to hit one of them, the young graduate student reportedly said, "Dr. Sherif, if you do it, I'm gonna hit you."

Fortunately, the older man came to his senses and stormed off angrily.

And while the three researchers were comically oblivious to the children's peaceful example of conflict resolution, they eventually decided that no one needed to set a forest fire that night—a stunt that had been intended to determine if the boys could overcome their differences to address a shared threat.

The story of Sherif's unusual research does not end there.

Undeterred by the failure of his experiment in upstate New York, Sherif created another fictitious summer camp one year later in Robbers Cave, Oklahoma.

Once again, he recruited a group of very similar young boys.

But in this now infamous experiment, the boys were not allowed to make friends with each other before being assigned to different teams.

Instead, the two groups were segregated on opposite sides of a lake.

The Rattlers and Eagles were not told about each other's existence when they arrived, and they engaged in the wholesome activities characteristic of U.S. Boy Scout camps in the mid-1970s.

Yet after a brief period of bonding, each group was told about the existence of the other and informed that the two groups would be competing against each other on the following day.

Though Sherif's first experiment had been a bust, his new experiment quickly devolved into something resembling William Golding's Lord of the Flies, a popular 1950s novel in which children stranded on an island resort to murder to resolve their conflicts.

Even though the boys had no reason to dislike each other a priori—and had once again been selected to be as "normal" as possible—they quickly began taunting each other without provocation.

After the Eagles defeated the Rattlers in a tumultuous game of tug-of-war, the Rattlers burned the Eagles' flag.

Members of each group soon refused to dine next to each other and conducted late-night raids to steal personal belongings from the other team that eerily resembled those of Sherif's research assistants in the previous year.

To his delight, Sherif's second experiment confirmed his hypothesis: All that is necessary for groups of people to develop antagonism toward each other is a collective identity.

The only difference between his failed experiment and this one was that the Eagles' and Rattlers' identities had time to grow when the two groups were isolated from each other.

Decades of subsequent research showed that people who are assigned membership in social groups will consistently prefer members of their own group and punish those outside its boundaries.

The phenomenon is not unique to children, either.

The human tendency to prefer members of our own group has been observed in every culture on Earth.

Scholars have also shown that in-group favoritism can be created even when people are assigned membership in groups that have even less meaning than the Eagles and the Rattlers.

Across many different studies, social scientists have discovered that members of such meaningless groups will penalize out-group members, even if doing so comes at a cost to their own side.

As the political scientist Lilliana Mason notes, perhaps we should not be so surprised that political parties—armed with sophisticated campaigns, media professionals, and long periods of time to coordinate their activities—can create such deep-seated animosity between Republicans and Democrats if similar animosity can be created so easily with completely arbitrary identities such as Eagles and Rattlers.

And if these same political parties are so effective at inflaming our passions, perhaps we should not be surprised that their power seems to increase when we find ourselves trapped within echo chambers—not unlike summer campers on opposite sides of a lake in rural Oklahoma.

Aus dem Buch “Breaking the Social Media Prism” von Chris Bail.