How and Why Do We Choose Our Friends?

“Friendship is born at that moment when one person says to another “What! You too? Thought I was the only one!” A quote from C.S Lewis, is this the only reason we build friendships? It turns out how we choose our friends goes beyond sharing similarities.

Neuroscience Explains

You may think that you chose your friends as you “share the same wavelength.” And according to neuroscience, this may be true. 

In a Dartmouth experiment, 42 students were asked to watch a series of videos while their neural responses were recorded by an MRI scanner. The researchers found that neural responses to videos were extraordinarily similar among friends and less so among people without a strong bond. This suggests that we tend to befriend people who perceive the world in a similar way to how we do.

The Alliance Hypothesis

Two psychologists, Peter DeScioli and Robert Kurzban, conducted an experiment using data from 11 million MySpace profiles to find how people ranked their friends in terms of closeness. They found that people ranked their friends based on how they were ranked by them. The higher the first person’s ranking, the higher the friend would rank them in return. And what’s more, the same results were found when the psychologists replicated the experiment offline. 



One of the largest data sets on friendship ever collected, the results suggest that reciprocated feelings are more important for how we perceive our friendships than mutual benefits, common tastes or geographic proximity. The data also shows that rather than choosing friends simply because we like them, we look for people who will side with us- and against others- during conflicts. According to DeScioli, “It’s not conscious, you generally just feel closer to those people.”

Are These Results Definitive?

Not necessarily. Both theories require future testing before they can be taken as fact. The researchers at Dartmouth for example want to research whether people naturally gravitate to others who perceive the world similarly or if we become more similar when we share experiences.

Meanwhile, the researchers for the Alliance Hypothesis are looking to test friendships in a lab setting to see how people respond offline when they encounter problems like bullying.

To conclude, it seems that to some degree, we do choose our friends based on commonalities. However, how prepared they are to defend us in times of conflict may be just as important.  



Nick Morgan

Created by New York City but exported to London. Currently I am studying Russian at University College London but I can not help myself from straying into countless other subjects that capture my interest. That is why I am currently in a love-hate relationship with the information age.