In the summer of 1954, twenty-two fifth-grade boys were taken out to a campground at Robbers Cave State Park, Oklahoma. Admittance had been quite selective. None of the boys knew each other. They were taken to the park in two separate groups of eleven. Ostensibly it was an unremarkable summer camp.

In fact, what the boys were heading to wasn’t that at all. They did have a very normal camp experience, certainly, but what they had really done for two and a half weeks was unwittingly take part in an elaborate and fascinating psychological experiment. Their parents had okayed it: the twenty-two boys of Robbers Cave were actually the basis of social psychologist Muzafer Sherif’s landmark study of group conflict.

There were two parts to Sherif’s hypothesis:

(1) When individuals having no established relationships are brought together to interact in group activities with common goals, they produce a group structure with hierarchical statuses and roles within it.

(2) If two in-groups thus formed are brought into a functional relationship under conditions of competition and group frustration, attitudes and appropriate hostile actions in relation to the out-group and its members will arise and will be standardized and shared in varying degrees by group members.

After conceiving of the experiment and working out the logistics of its program and setting⁠— a Boy Scouts’ campground⁠— Sherif and his colleagues had chosen their campers carefully. To decrease the potential impact of variables (other factors that could prompt hostility), Sherif and his colleagues had looked for boys of similar age and intelligence, all Caucasian and Protestant, all middle-class, none from insecure homes and none known to be troublemakers. They had aimed for a balance of different kinds of mental and physical strengths. It was also very deliberate that the boys had never met before; this was in accordance with the first part of Sherif’s hypothesis. Any preformed alliances would throw off the study.

The aim was to establish immediately a sense of group unity within each group of eleven boys. Taking the two groups to Robbers Cave separately was a major part of this; it also kept the other side wholly unknown. None of the boys were even aware yet that there was a second group. That would only be revealed once a strong sense of group identity had been forged.

Once at the park, the activities continued to encourage the groups to work together. These were typical aspects of camp: preparing food, putting up the tents, etc. They also played sports, went swimming, and performed for each other. This was all very successful – in fact, as the boys bonded each of the two groups chose to give itself a name, which was not an intentional part of the experiment. One became the Eagles, the other the Rattlers. Precisely as Sherif had hypothesized, there came to be a social order very quickly in each group. Clear leaders emerged from both. And, as the boys became vaguely aware that theirs was not the only group, they actually asked to be put into competition with them.

This, of course, was exactly what the psychologists had planned to happen. The two groups were brought together. They would be pitted against each other in a lengthy tournament of sports and other challenges; the winner would be awarded a medal and a pocketknife. The psychologists’ aim was to prompt each team to see the other as an ‘enemy’ of sorts, and test the second part of the hypothesis.

Again, the predictions were confirmed; this is exactly what happened. The boys began calling the other team names almost immediately, while glorifying the members of their own ‘side’. They threatened to fight members of the opposing team. The Eagles snuck into the Rattlers’ camp, stole their flag, and burned it. The Rattlers returned the gesture. As this happened, the more aggressive boys became the more popular within their groups. After the Eagles won the competition, the Rattlers invaded their tents and took whatever knives and medals they could find. Although the park had been named for the suspicion that Wild West outlaws Jesse James and Belle Star had once hidden there, “Robbers Cave” was beginning to seem an apt name for the camp.

Then came the most interesting twist: the noncompetitive activities. Both groups were again brought together, just for meals and other such basic settings. The hostility did not die down; the groups remained locked in animosity. So the psychologists tried something a bit more assertive: forcing the boys to all work together in a cooperative effort, to achieve what are called superordinate goals.

They did this in several stages. First, the water supply to the camp was cut off (thereby necessitating as much help to check the pipes as necessary). Then, they were offered a movie that they were told the camp wasn’t quite able to pay for (and each team paid equally). Finally, a broken-down truck was deliberately left on the premises of the camp; nearby one of the organizers had left a tug-of-war rope to see whether any of the boys would suggest using it. Sure enough, one of them did – and all the boys, Eagle and Rattler alike, pulled on the rope together to help get the truck started again.

The changes after this point were striking indeed. The exchange of insults abruptly ended, for the most part. Neither side seemed to bear much of a grudge for the earlier thefts and enmity. Several pairs of boys from opposite teams made friends. But it didn’t stop there; at the end of the two and a half weeks, the campers insisted that the camp leaders allow them all to travel home on the same bus, instead of the divided way in which they had arrived. On this bus, they did not sit according to their earlier groups. Furthermore, at one point the bus stopped at a café. The Rattlers, who had won money in a contest during the ‘competitive’ stage, spent their money not only on themselves but on the Eagles as well.

Overall, the experiment was seen as a success. Not only had both aspects of Sherif’s hypothesis been verified, but several further conclusions had been reached. One was the observation that removing the boys from the competitive settings was not enough to reverse intergroup hostility. Another was that major differences in background are not necessary for conflict to emerge.

The Robbers Cave experiment has been somewhat criticized more recently. Some psychologists point out that such conflicts between groups depends on a high degree of group identity and loyalty. Others argue that if the two groups had failed to achieve the superordinate goals, the groups would have blamed each other, thus exacerbating the conflict instead of relieving it. Still more say that the experiment has little real-world applicability due to there being so many more variables involved in real conflicts – on the worldwide scale, for example. However, through their intricate planning, Sherif and his colleagues had laid the groundwork for what would come to be known as the realistic group conflict theory, which has come to be invaluable in psychology, sociology, and economics. Also, as a nice side-effect, they had given twenty-two boys from Oklahoma City quite a few new friends.