What can an astronaut, baby sloths, a sentimental music video and an MRI scanner reveal about your friends? Quite a lot, a new study reveals.
Researchers put 42 business school students in an MRI machine and showed them a series of 14 videos. As they watched the clips, the scanner recorded the activity in their brains.
Those patterns could be used to predict which students were friends and which were merely classmates, according to a study published Tuesday in the journal Nature Communications.
"Neural similarity was associated with a dramatically increased likelihood of friendship," the team from the University of California, Los Angeles and Dartmouth College reported.
"These results suggest that we are exceptionally similar to our friends in how we perceive and respond to the world around us," they added.
That might seem obvious to anyone who's ever heard that "birds of a feather flock together." But until now, no one had ever put that maxim to the test by examining the cognitive activity of friends in real time.
The researchers, led by UCLA social psychologist Carolyn Parkinson, started with an entire cohort of students from Dartmouth's Tuck School of Business. All 279 of them were asked whether they were friends with each of their fellow students. (A "friend" was defined as someone you'd go out with for a drink, a meal, a movie or other "informal social activities.")
If two students named each other, they were considered friends for the purposes of the study. Researchers used those responses to reconstruct the social network of the business school class.
In the next phase of the study, 42 of the students agreed to lie in a functional MRI scanner while they watched videos for 36 minutes.
The clips ranged in length from 88 seconds to more than 5 minutes, and were chosen to evoke a range of emotions in viewers.