If you and your best friend love laughing at the same sitcoms or tearing up during the same documentaries, science says that’s no coincidence. A new study has found that people whose brains react in similar ways to the same videos are more likely to form lasting friendships.
Researchers at UCLA and Dartmouth followed a group of MBA students from their arrival on campus. Before the students had a chance to mingle, 41 of them watched a series of movie clips—ranging from comedies and debates to nature documentaries—while inside a functional MRI scanner, or fMRI.
The scientists then tracked the students’ social networks for the next eight months. Strikingly, those who processed the videos in similar ways were significantly more likely to become friends later, and to grow closer over time, compared with peers whose brains reacted differently.
“The current results suggest that individuals who process audiovisual movies in a similar fashion are exceptionally likely to become friends in the future and grow closer in social ties over time,” researchers wrote in the paper.
Rather than being just about shared taste in shows or sports, the findings suggest that deeper similarities in how our brains interpret the world may help explain why some friendships last while others fade.
Beyond ‘Birds of a Feather’
Friendship has long been explained by homophily—the idea that “birds of a feather flock together.” People often bond through shared backgrounds, demographics, or hobbies.
But the new findings suggest something deeper at play: friendships may be rooted in shared ways of perceiving and making sense of the world.
Brain regions linked to emotion, attention, and meaning-making—including the orbitofrontal cortex (which processes subjective value), the angular gyrus, and the medial prefrontal cortex—showed the strongest similarities among people who later became close.
The authors wrote that the results suggest, “pre-existing similarities in how people interpret, attend to and emotionally respond to their surroundings are precursors of future friendship and increased social closeness.”
Lasting Friendships
The effect wasn’t just about initial sparks. Students whose neural patterns aligned were not only more likely to become friends, but also more likely to stay close months later.
The researchers argue that while some friendships form from convenience—like sitting next to someone in class—deeper, longer-lasting bonds may stem from this neural compatibility. Friendships born out of circumstance often faded, while those grounded in shared brain responses endured.
References
Shen, Y. L., Hyon, R., Wheatley, T., Kleinbaum, A. M., Welker, C. L., & Parkinson, C. (2025). Neural similarity predicts whether strangers become friends. Nature Human Behaviour. https://doi.org/10.1038/s41562-025-02266-7
Read the full article here
