Now experiments can reveal who is friends with whom based on the way their brains respond to definite stimuli, according to a study published in Nature Communications.
Studying a cohort of graduate students, the researchers estimated social distance based on what the subjects mutually admitted to. Videos spanning a range of genres and topics – politics, comedy, music, science, etc were shown to 42 students and their brain responses monitored. Pairwise they were then compared. They found that responses were most similar between friends, and stretched across brain regions involved in emotion, directing attention and high-level reasoning. The fMRI response similarity could in fact predict the social distance between people.