You and Your Best Friend Are More Similar Than You Would Ever Think

It’s widely understood that people pick friends who are like them—who have shared interests, are of a close age, and of a similar education level, etc. However, new research published recently in Nature shows that actually best friends aren’t just similar on the surface level but the neurological level. Dr. Parkison and colleagues from Dartmouth revealed that close friends share similar brain waves and neurological response patterns.

In this study, the researchers surveyed 279 graduate students at Dartmouth and mapped out the social network among them—finding out who is best friends with who. Then they asked willing participants to watch a series of videos on topics ranging from Liam Neeson to college football while a fMRI device tracked the blood flow patterns in their brains,  as blood flow can help determine neural activity.

After controlling for factors that would elicit a similar neurological response (i.e. similarities in ethnicity, family income, etc.), it was found that close friends had extremely similar neural responses. The closer friends were to each other, the more similar their neurological responses to the videos, and the less close friends were to each other, the less similar their neurological responses. The areas in the brain that exhibited the most similar neural responses were in the nucleus accumbens (lower forebrain) and the parietal lobule (top, back of the brain)—parts that are associated with reward processing and one’s allocation of attention to the external environment, respectively. This suggests, according to the study in Nature, that close friends are “exceptionally similar in how they attend to, interpret, and emotionally react to their surroundings.”

These findings give a scientific basis to the sense that close friends process the world in similar ways--and share a connection that runs even deeper than we would ever guess.

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