"All my black friends have a bunch of white friends. And all my white friends have one black friend." 
 
 That's the memorable punchline of a Chris Rock bit from 2009 on interracial friendships. And according to some recent number-crunching by Robert Jones of the Public Religion Research Institute, there's a good deal of truth to that statement. 
 
 Let's consider the average white American and the average black American, and let's say, for simplicity's sake, that each of them have 100 friends. If you were to break down their respective friend networks by race, they would look something like this. 
 
 If you're interested in how PRRI arrived at these numbers, see the methodological note at the bottom of this post. 
 
 In a 100-friend scenario, the average white person has 91 white friends; one each of black, Latino, Asian, mixed race, and other races; and three friends of unknown race. The average black person, on the other hand, has 83 black friends, eight white friends, two Latino friends, zero Asian friends, three mixed race friends, one other race friend and four friends of unknown race. 
 
 Going back to Chris Rock's point, the average black person's friend network is eight percent white, but the average white person's network is only one percent black. To put it another way: Blacks have ten times as many black friends as white friends. But white Americans have an astonishing 91 times as many white friends as black friends. 
 
 There are a number of factors driving these numbers. Simple population counts are one of them: There are more white people than black people in the United States, so it makes sense that the average American is going to have more white friends than black friends. 
 
 Another factor is our tendency to seek out and associate with people who are similar to us in any number of ways - religiously, politically, economically and, yes, racially, too. The polite term for this phenomenon is "sorting," and it affects everything from political polarization to income inequality to the racial differences in friend networks seen above. 
 
 As PRRI's Robert Jones writes in the Atlantic, Americans' segregated social circles have influenced responses to the events in Ferguson, Mo., over the past few weeks. Polls show deep divides between blacks and whites on everything from the role of race in Ferguson to the appropriateness of responses by protestors and police. 
 
 The numbers above offer insight into why so many whites have expressed bafflement over protesters' responses to the shooting of Michael Brown. The history between many black communities and the police forces that serve them is long, complicated, often violent and characterized by an extreme imbalance of power. But as Robert Jones notes, most whites are not "socially positioned" to understand this history -- simply because they know few people who've experienced it. 
 
 To be fair, the numbers suggest there is plenty of racial self-selection in black Americans' friend networks, too. But focusing solely on black-white relations, there's a pretty big difference between having only one member of a given race in your friend network and having eight of them. 
 
 In fact, PRRI's data show that a full 75 percent of whites have "entirely white social networks without any minority presence." The same holds true for slightly less than two-thirds of black Americans. 
 
 The implication of these findings is that when we talk about race in our personal lives, we are by and large discussing it with people who look like us. 
 
 How PRRI calculated the racial breakdowns of friend networks 
 
 As part of their American Values Survey, PRRI researchers asked respondents to name up to seven people with whom they regularly discussed important matters. They then asked a battery of demographic questions about these people -- their relationships to their respondents, as well as their gender, religion and, germane for these purposes, their race. They used these numbers to derive average racial breakdowns of the friend networks of the average black, white and Hispanic survey respondent. ||||| One reason for the racial divide over Michael Brown's death is that white Americans tend to talk mostly to other white people. 
 
 Lucas Jackson/Reuters 
 
 The shooting of unarmed black teenager Michael Brown by a white police officer in Ferguson, Missouri, and the anger poured out in response by Ferguson’s mostly black population, has snapped the issue of race into national focus. The incident has precipitated a much larger conversation, causing many Americans to question just how far racial equality and race relations have come, even in an era of a black president and a black attorney general. 
 
 Polls since the incident demonstrate that black and white Americans see this incident very differently. A Huffington Post/YouGov poll finds that while Americans overall are divided over whether Brown's shooting was an isolated incident (35 percent) or part of a broader pattern in the way police treat black men (39 percent), this balance of opinion dissipates when broken down by race. More than three-quarters (76 percent) of black respondents say that the shooting is part of a broader pattern, nearly double the number of whites who agree (40 percent). Similarly, a Pew Research Center poll found that overall the country is divided over whether Brown’s shooting “raises important issues about race that need to be discussed” (44 percent) or whether “the issue of race is getting more attention than it deserves” (40 percent). However, black Americans favor the former statement by a four-to-one margin (80 percent vs. 18 percent) and at more than twice the level of whites (37 percent); among whites, nearly half (47 percent) believe the issue of race is getting more attention than it deserves. 
 
 Clearly white Americans see the broader significance of Michael Brown’s death through radically different lenses than black Americans. There are myriad reasons for this divergence, from political ideologies—which, for example, place different emphases on law and order versus citizens’ rights—to fears based in racist stereotypes of young black men. But the chief obstacle to having an intelligent, or even intelligible, conversation across the racial divide is that on average white Americans live in communities that face far fewer problems and talk mostly to other white people. 
 
 A 2012 PRRI survey found that black Americans report higher levels of problems in their communities compared to whites. Black Americans were, on average, nearly 20 percentage points more likely than white Americans to say a range of issues were major problems in their community: lack of good jobs (20 points), lack of opportunities for young people (16 points), lack of funding for public schools (19 points), crime (23 points), and racial tensions (18 points). 
 
 Disparities in Reported Community Problems, by Race 
 
 Public Religion Research Institute, Race, Class, and Culture Survey, September 2012 
 
 These incongruous community contexts certainly set the stage for cultural conflict and misunderstanding, but the paucity of integrated social networks—the places where meaning is attached to experience—amplify and direct these experiences toward different ends. Drawing on techniques from social network analysis, PRRI’s 2013 American Values Survey asked respondents to identify as many as seven people with whom they had discussed important matters in the six months prior to the survey. The results reveal just how segregated white social circles are.
– Three-quarters of white Americans lack any minority friends, a survey finds: Their social networks, according to the Public Religion Research Institute, are "entirely white." The average white person with 100 friends, meanwhile, would have a single black friend, a single Latino friend, one Asian friend, and one mixed-race friend, the Washington Post reports. A black person with 100 friends would typically have eight white friends, per the survey. The data seem to prove the Chris Rock joke that "all my black friends have a bunch of white friends—and all my white friends have one black friend," Christopher Ingraham notes at the Post. Among black Americans, about 65% have social networks consisting of only black people, the survey finds, per the Atlantic. For Hispanic Americans, the figure is 46%. The homogeneity among white people might be explained in part by our habit of making friends who are similar to us, Ingraham notes. There's also the persistent segregation in our communities, notes Zak Cheney-Rice at News.Mic: Fueled by housing discrimination and poverty, "geographical divides between white and black Americans are a defining characteristic of most US cities," he writes. Adds Ingraham: "The implication of these findings is that when we talk about race in our personal lives, we are by and large discussing it with people who look like us."