It’s often assumed that we are moved to be philanthropists by being attentive to others who are less fortunate than ourselves.

But could it be that being tuned into others whose circumstances are very much like our own is just as important to the philanthropic impulse?

This is the rather surprising suggestion that emerges from Tyler Cowen’s acclaimed new book The Complacent Class: The Self-Defeating Quest for the American Dream.

Cowen, who holds the Holbert L. Harris Chair of Economics at George Mason University, shows that neighborhoods are becoming increasingly segregated by income, education, and culture. Digital technologies allow us to sort further ourselves so that we meet others with opinions and tastes that match our own—or even to avoid social interactions altogether, by letting us buy groceries or watch a movie on a computer at home rather than only in a store or theater.

Cowen’s findings about increasing segmentation of society will be familiar those who have read Charles Murray’s Coming Apart: The State of White America, 1960–2010 or Robert Putnam’s Our Kids: The American Dream in Crisis.

But while Murray and Putnam conclude that those near the top of the socio-economic ladder are faring (more or less) just fine, Cowen sees things quite differently. On Cowen’s account, the wealthy and even the upper middle class have become a “complacent class,” of which the defining characteristic is “the lack of a sense of urgency” to achieve something great, or at least new and different.

(Before you say, ah, but that’s not me, you can try Cowen’s quiz to rate your own level of complacency. I scored “comfortable.”)

And where does a sense of urgency come from? From the spur of seeing others who are similarly situated but doing just a little bit better than we are. Drawing on Tocqueville, Cowen argues that when people

…can observe the situations of many other people who are more or less on an equal plane … [they] become acutely aware of how they differ from others, of what they are lacking, and of how they might possibly obtain a better state of affairs. They are thereby driven to a restless pursuit of both wealth and higher social status.

This makes sense—we might not suppose that we can do better than those who started far ahead of us in life, but it pricks our pride when we see childhood friends or college classmates enjoying greater wealth and prestige, and we think we should be able to figure out how to attain the same.

The trouble, Cowen suggests, is that today “Americans might turn their backs on comparing themselves with similar others and striving to do better, and settle into their comfortable cocoons.”

It seems that we may compare ourselves less with similar others for at least a couple reasons: we interact less with others generally, but also we have a harder time recognizing what “people like us” do because it is harder to discern whose circumstances are similar to ours (for example, Cowen notes, now that even billionaire Bill Gates wears casual khakis, clothing is no longer a sure clue as to social standing).

So what does this have to do with philanthropy and civil society? Philanthropy seems to be an activity that is supported by acute awareness of one’s peers, in which what Cowen calls “superclusters of cooperation” emerge among the similarly situated. If someone sees his peers giving to charity, or organizing to address a community problem, pride and ambition prompt him to join in to keep up.

The complacency that Cowen worries about has not affected philanthropy overall—as Cowen notes, we Americans “even rate as the global number one” as philanthropists. Among the very wealthiest, there are certainly extra supports to sustain superclusters of cooperation (the Giving Pledge, for example, has made the philanthropic commitments of the very wealthy more visible to each other and to the public).

But Cowen’s arguments suggest that complacency that has infected other aspects of American life may eventually affect philanthropy and contributions to civil society among those who are not in the ranks of wealthiest.