Brain scans can now predict who are likely to become friends. A new research shows that social ties are forged at a higher-than-expected rate among people with neural similarities.

A psychology research from the University of California in Los Angeles and Dartmouth College concluded that individuals develop affinity and attraction to other persons who see the world in a similar way as them.

The research revealed that people who perceive and respond to the world in similar ways are more likely to become friends.

Neural Homophily

Researchers recognize that individuals have the tendency to bond with or befriend other people who are similar to them in terms of age, gender, and other physical attributes.

This intuition called homophily, is considered as an ancient principle of organizing social networks.

The study, however, wanted to know if friendships are associated with similarities in real-time mental responding.

"I think we all have the intuition that friends see the world the same way, although it hasn't been demonstrated," says Thalia Wheatley, senior author on the study and an associate professor of psychological and brain sciences at Dartmouth.

Social Mapping And Brain Scan Methods

For the study, 280 graduate students of Dartmouth College in Hanover, New Hampshire were asked to identify their real life social network — possible friends, friends of friends, and friends of friends of friends. Students who identified each other were mapped and friendships were translated to degrees of separation in the social network.

In the second phase of the research, scientists used a magnetic resonance imaging scanner to determine if neural homophily or neural responses are similar among friends.

Forty-two students, lay on a functioning MRI scanner and watched short audiovisual video clips that were chosen to evoke varying emotions from viewers.

Each participant watched the videos in the same order for 36 minutes. While participants watch, the scanner recorded the responses of 80 separate regions of their brains. The researchers compared scans from pairs of students to know how similar their responses were.

The results revealed that the brain response of pairs who were identified as friends was more similar than pairs who were not friends.

"We are a social species and live our lives connected to everybody else," said Wheatley. "If we want to understand how the human brain works, then we need to understand how brains work in combination - how minds shape each other," she added.

Similar Neural Response

"Neural similarity was associated with a dramatically increased likelihood of friendship," the researchers 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.

The study is published in the journal Nature Communications.