A new study suggests that brains of friends respond to real-world stimuli in a similar manner, confirming what many of us might have suspected all along.
The study, the first of its kind, sheds light on how and why friendships form, and the results can be used to better our understanding of how our minds influence and shape one another.
The researchers at Dartmouth College in the US, found that it is possible to predict who people’s friends are just by looking at and comparing their neural responses to video clips, which were used to simulate real-life stimuli.
Friends showed the most similarity in neural activity patterns, followed by friends-of-friends who, in turn, had more similar neural activity than people three degrees removed. The findings were published in the journal Nature Communications.
“Neural responses to dynamic, naturalistic stimuli, like videos, can give us a window into people’s unconstrained, spontaneous thought processes as they unfold,” says the study’s lead author, Carolyn Parkinson, now the director of the Computational Social Neuroscience Lab at the University of California, Los Angeles.
“Our results suggest that friends process the world around them in exceptionally similar ways.”
The study explored the social ties and friendships in a sample of 280 graduate students, of which 42 were made to watch a range of video clips, while their brain responses were recorded inside a functional magnetic resonance imaging (fMRI) scanner.
To assure that brain responses of participants varied significantly from one clip to another, different genres of videos were chosen, and ranged from politics to science, comedy and music.
All test subjects watched the videos in the same order, having received the same instructions. The researchers then compared the neural responses across their subjects to determine if pairs of students who were friends had similar brain activity than pairs socially further removed from one another.
Their findings revealed that the neural response similarity was the highest in friends, especially in brain regions involved in emotional responding, and high-level reasoning. The similarities were present even when accounting for different variables involved.
This enabled researchers to predict people’s social connections, based on their brain’s responses to the video stimuli and conclude that friends view the world in a similar way, both on an emotional, and rational level.
“We are a social species and live our lives connected to everybody else. If we want to understand how the human brain works, then we need to understand how brains work in combination – how minds shape each other”, explains senior author Thalia Wheatley, an associate professor of psychological and brain sciences at Dartmouth.
This study built on the researchers’ earlier work, which found that our brains respond to seeing someone we know by immediately evaluating their position in our social network. Going forward, the team plans to investigate whether we naturally gravitate towards people who see the world similarly to us, and whether we become more similar to each other by sharing experiences.