"What? You too? I thought I was the only one." Have you ever said to someone? If so, you may have ended up becoming friends.
It seems that similarity often helps form a friendship. Aristotle once said, "Some define (给……下定义) it (friendship) as a matter of similarity; they say that we love those who are like ourselves."
Now, there are some scientific explanations for this idea. The scientists from the University of California said friends have similar brains, Scientific American reported.
The scientists invited 42 university students to take part in a scientific test. Each student watched the same set of videos. At the same time, the scientists scanned (扫描) their brains and recorded their brain activities.
According to their study, friends who watched the same videos reacted (反应) in similar ways. Similar parts of their brains lit up while watching the videos, especially the parts that were connected with motivation, learning and memory. However, people who weren't friends had different reactions to the same videos.
"Having close friends whose brains react like ours may be rewarding because it reinforces (加强) one's own values, opinions and interests," lead scientist Carolyn Parkinson told Business Insider.
But brain similarity is not the only thing that can result in a friendship. Scientists from the University of Leipzig, Germany, found that a friendship is also based on how physically close you are to someone. They did a scientific test on first-year college students who met in class for the first time. In this test, students who sat next to each other were more likely to become friends.
