Friends’ brains respond similarly to events in video clips, shows a study published in Nature Communications. These similarities in neural responses decrease as distance between people in a social network increases. The authors show that this relationship could be used to predict the likelihood of particular friendships within a social network.
Previous research has shown that people tend to be friends with those who are of a similar age, gender, ethnicity, and other demographic categories. However, it is not clear whether friends could resemble each other not only in such external characteristics, but also in the way they may experience the world.
Carolyn Parkinson and colleagues quantified the social network of a cohort of 279 graduate students. 42 students (12 women and 30 men, aged 25 to 32) from this cohort then participated in a functional magnetic resonance imaging (fMRI) experiment during which they watched a collection of video clips spanning different topics and genres (including comedy, documentaries and debates) while the researchers measured their brain activity. They found that activity in areas of the brain implicated in interpreting the sensory environment and emotional responses, as measured by fMRI responses, was more similar between friends watching the same clip compared to people further apart in the social network. Additionally, the similarity in brain activity between two people could be used to predict the friendship status and social distance of new pairs of individuals within the group of participants.
Based on their results, the authors suggest that people may be similar to their friends in the way that they perceive and respond to the world.