We all know the saying: ‘the enemy of my enemy is my friend’. That may sound logical, but it has never been proven. American researchers have finally succeeded in doing this with the help of a new mathematical model.
They decided to test the social balance theory again, which was devised in the 1940s by the Austrian psychologist Fritz Heider. The theory explains how people naturally strive for harmony in their social circle. According to Heider, four rules lead to this: an enemy of an enemy is a friend, a friend of a friend is a friend, a friend of an enemy is an enemy and an enemy of a friend is an enemy.
Too simple models
Numerous studies have tried to confirm this theory, but have failed because real social networks deviate from perfectly harmonious relationships. Most network models were too simplified to really capture the complexity of human relationships.
But the researchers of the Northwestern University have managed to integrate the two most important pieces that make Heider’s social framework sound: in real life, not everyone knows each other and some people are more positive than others. Researchers have known for some time that these two factors influence social connections, but existing models could only take one factor into account at a time. A solution has been found for this in the new study. This way, the researchers were finally able to confirm Heider’s famous theory, eighty years after it was devised.
Social intuition
The new model is much more than a fun thought exercise. It can also be used in practice to better understand social dynamics. Think of international relations, but also political polarization in your own country. But it is actually useful for any system with a mix of positive and negative interactions, such as even the combination of drugs.
“We always thought this social intuition was correct, but we didn’t know why,” says researcher István Kovács. “For decades we got it wrong. That’s because real life is complicated. We realized that we had to take both factors into account at the same time: who knows who and some people are just nicer than others.”
Polarization
If you look at groups of three people, Heider’s assumption remains that people strive for pleasant, harmonious relationships. In balanced social relationships, all people like each other. Or if one person doesn’t like the other two, then those two are friends. In an unbalanced relationship, all three people don’t like each other, or one person likes two others who don’t like each other, but that would lead to great tension.
“That seems very much in line with our social intuition,” Kovács responds. “You can see how this leads to extreme polarization, for example in politics. If everyone you like also dislikes all the people you don’t like, the result is two groups that hate each other.”
To test the theory, the researchers used four data sets, consisting of comments on social news site Slashdot, contact between members of Congress from the American Congress, interactions between bitcoin traders and product reviews on a consumer site.
The real life
What the Americans do better than previous researchers is take into account real life, in which not everyone knows each other within a social network. It may be that you have never met a friend’s friend. They also noted that some people are simply friendlier. They are more likely to have positive interactions and will have fewer enemies.
And then the miracle could happen: large social networks suddenly turned out to be in line with Heider’s social balance theory. “We now know that you have to take these two factors into account,” says Kovács. “If you don’t do that, you won’t arrive at the right mechanisms. It seems complicated, but it’s actually quite simple math.”
Practical applications
The researcher now wants to work on practical applications of his findings by, for example, developing policy to combat political polarization, but the new model can be applied even more broadly than just for social groups. “We can also look at excitatory and inhibitory connections between neurons in the brain or interactions of different combinations of drugs. The social network study has been an ideal playground for research, but our main goal is to go beyond interactions between friends and look at other complex networks.”
