100 Things You Should Know About People: #88 — Your Brain Has A Special Response To People You Know

Your Uncle Arden invites you over to watch the World Cup and tells you to bring some friends. When you get there you see that there are several people you know (relatives and friends of relatives), and some you don’t know. It’s a lively bunch, and over food and the game on TV, lots of topics are covered, including soccer and politics. As you would expect, you have similar opinions on the topics of soccer and politics with some of your friends and relatives, and you disagree with some of them. You actually have more in common, in terms of soccer and politics, with some of the strangers you just met today than you have with some of your friends and relatives. The chart below shows the four possible combinations of people and similarities:

Chart of relationships and similarities

Does your brain react differently to these 4 combinations? — The questions that Fenna Krienen conducted research on are: Do you make judgments about other people based on how similar they are to you? Or is it more important that they be close to you, either a close friend or a relative? And if there are differences, will they show up on fMRI brain scans? When you think about people that you don’t know, but feel similar to, do the same brain regions light up as though you were connected to them through kinship or previous friendship?

Your brain responds to people you know — Krienen and team found tested these theories. They found that when people answered questions about friends, whether or not they felt they were similar to their friends, the medial prefrontal cortex (MPFC) was active. The MPFC is the part of the brain that is active in perceiving value and regulating social behavior. When people thought about others that they don’t know, but have common interests with (are similar to), the MPFC was not active.

What do you think? Does your brain respond specially to people you know?

If you want to read the research:

Krienen, Fenna M.,Pei-Chi, Tu, & Buckner, Randy L. (2010). Clan mentality: Evidence that the medial prefrontal cortex responds to close others. The Journal of Neuroscience, 30(41), 13906-13915; doi:10.1523/JNEUROSCI.2180-10.2010.