Researchers Sharad Goel, Winter Mason, and Duncan Watts replicated this finding in a clever study using a Facebook app: Their survey participants answered a series of questions about themselves on a number of social, economic, and political issues (as well as some lighthearted questions such as "would you rather have the power to read minds or the power to fly?"). Respondents were also asked the same questions about their friends and, as expected, people reported that their friends agreed with them about 80 percent of the time on typical issues.
When the researchers went back and checked what the friends actually wrote -- remember, this was all done on Facebook, so they knew who was friends with whom -- they found out that the actual rate of agreement was only 70 percent. So, yes, your friends agree with you -- but not as much as you think.
We looked at this another way by analyzing the responses of self-identified Democrats and Republicans to questions on several political issues. Only 6 percent of Americans are Republicans who think of themselves as conservative, oppose abortion, and have conservative views on affirmative action and health policy. Fully 85 percent of self-declared Republicans are nonconservative or take a nonconservative stand on at least one of these three traditional issues. On the other side, almost 90 percent of Democrats are nonliberal or have nonliberal views on abortion, affirmative action, or health policy.
In his bestselling book The Black Swan, investment guru Nassim Taleb asks "why those who favor allowing the elimination of a fetus in the mother's womb also oppose capital punishment." In fact, surveys find that the death penalty has been supported by 74 percent of those who oppose abortion and 76 percent of abortion-rights supporters. There's no correlation at all (in the general population).
Despite what you might have heard, Americans are mixed in their political views. This makes sense. Consider your own attitudes. You try your best to consider each issue on its merits. And there's no reason to expect that others are less reflective than you -- at least not on average. Consider even those Mississippi Republicans who oppose interracial marriage. They're not following any party line.
When it comes to important political issues, Americans have a diverse mix of attitudes that generally does not line up with either political party. Yes, the people you know probably agree with you on many things, but not as much as you think.