How often do you and your friends agree?

According to recent work by Winter Mason, Duncan Watts, and myself [Sharad Goel], you probably don’t know them as well as you think. In particular, we found that when friends disagree on a political issue, they are unaware of that disagreement about 60% of the time. Even close friends who discuss politics are typically unaware of their differences in opinions.

You probably can guess my reaction.  (Or at least you think you can.)  Since I am always right, and my friends are right more often than they are wrong, I am right to assume that they agree with me more often than not.

It turns out that my distant friends are right just about as often as my close friends:

people consistently overestimate the likelihood that their friends agree with them on political issues. Notably, even though close friends (so-called strong ties[1]) are in reality more likely to agree with one another than distant friends, people do not appropriately adjust their perceptions. In other words, though we think close and distant friends are about equally likely to agree with us on political issues, in reality we are much more likely to agree with close friends.

I am very interested in this kind of survey work because I think that people do overestimate how similar they are to the rest of the world and I think it has important consequences.  But perhaps for different reasons than these authors are emphasizing.

At the margin people are too reluctant to express themselves because they assume that what they have to say is obvious.  But in fact the obvious thing is exactly what you want to say.  Because the more obvious the thought the more likely it is uniquely yours and the more valuable it is to others.