Last updated January 31, 2018 at 10:10 am
Similarities in neural responses could be used to predict who your friends are.
Have you ever wondered about who your real friends are? Researchers took a group of students to create a social network using an online survey. With this, they observed the brain’s neural responses to video clips from some of the subjects to determine the relationship between social network proximity to neural similarity.
Using magnetic resonance imaging (MRI) to scan subjects’ brains from 42 people, they found that “neural responses when viewing audiovisual movies are exceptionally similar among friends”.
Relationships were mutually reported and experiments compared in pairs and sorted into degrees of friendship: friends, friends-of-friends, and friends-of-friends-of-friends.
The videos shown were a mix of genres, from comedy such as America’s Funniest Home Videos, to documentaries about a baby sloth sanctuary, sports and political debates, designed to emulate channel surfing.
“Neural responses to dynamic, naturalistic stimuli, like videos, can give us a window into people’s unconstrained, spontaneous thought processes as they unfold,” says lead author Carolyn Parkinson.
“Our results suggest that friends process the world around them in exceptionally similar ways.”
Difference between old friends and new ones
The findings revealed that neural response similarity was strongest among friends – a pattern shown across brain regions involved in emotional responding, directing one’s attention and high-level reasoning.
Even when the researchers controlled for variables, including left-handed or right-handedness, age, gender, ethnicity, and nationality, the similarity in neural activity among friends was still evident.
The team also found that MRI response similarities could be used to predict not only if a pair were friends but also the social distance between the two.
There are limitations to this study.
Could it be perhaps that the duration of friendships can be an influential factor? Could longer friendships result in more similar patterns than newer friendships?
Is this the chicken or the egg?
Since this response between friends is more generally a reflection of social network proximity, they acknowledge there are other networks that subjects would have and thus it would be interesting to know if similarities in neural responses are shared among family relatives, for example.
For the study, the researchers were building on their earlier work, which found that as soon as you see someone you know, your brain immediately tells you how important or influential they are and the position they hold in your social network.
They highlight the chicken-and-egg nature of friendships in their paper, writing “do we become friends with people who respond to the environment similarly, or do we come to respond to the wold similarly to our friends?”
The research team plans to explore if we naturally gravitate toward people who see the world the same way we do, if we become more similar once we share experiences or if both dynamics reinforce each other. They suggest that it would be interesting to find out if strangers can become friends if they already share similar neural responses.
Think about this the next time you go watch a movie with your closest friends.
This research was published in Nature Communications.