Do you know your neighbors? Stop and think for a minute. If you defined your neighborhood by a geography that consists of, say, 25-30 households, how many of those homes contain someone you could greet by name? If you’re struggling to come up with more than a few, you’re not alone.

A 2005 study, conducted by researchers at Georgetown University, found that 47% of Americans knew “none, almost none, or a few” of their neighbors by name. This represents a dramatic change from the tightly-knit “townshipped” communities filled with diverse but mutually supportive inhabitants that observers as far back as Alexis de Toqueville have praised as the bedrock of American democracy.

According to researcher Marc Dunkleman, author of The Vanishing Neighbor, one possible explanation for the precipitous decline in neighborly interactions has to do with “subtle changes in the American routine,” which have been driven by dramatic technological, economic, and demographic shifts since the decades following World War II.

Essentially, Dunkleman argues, Americans used to live in a world that more readily facilitated face-to-face interactions with neighbors. Shopping options were limited to what we found on our community’s version of Main Street, for example, which meant that everyone who needed new shoes found themselves perusing the selection at the same local store, rather than ordering the latest styles from Zappos.com. Before the widespread use of air conditioners, summer nights were spent cooling off on porches or stoops which, as a writer for the New York Times recently reported, were, in another era, ground zero for neighborliness. With more and more Americans living in suburban landscapes built around driving, we now move most fluidly from a closed garage to a far-off parking spot—leaving sidewalks, where we might readily bump into neighbors, largely unused. And jobs to which we commute longer and longer distances now dominate the average American’s routine, crowding out the time we once had for casual social interactions.

Academics have noted such changes and their consequences for decades—most prominently since the publication of Robert Putnam’s seminal work, Bowling Alone, which detailed the myriad ways in which social capital, civic engagement, and community cohesion have been in marked decline since the postwar era. But Dunkleman theorizes that what’s actually going on is not necessarily a full-scale decline in social interactions, but rather a reorganization of those interactions around the new technologies and economic realities that now define “the rhythms of ordinary American life.”

Dunkleman’s thesis is based upon the work of Robin Dunbar, an anthropologist who discovered a correlation between the evolution of the size of the human brain and the evolution of the size of human communities. The larger the brain, Dunbar found, the greater our capacity to sustain more a complex network of social ties. The types of ties modern, big-brained humans tend to form can be categorized into what Dunkleman calls three “rings.” The inner ring contains the handful of people upon whom we depend for deep and regular support. The outer ring consists of the people with whom we sustain passing interactions—often of a transactional nature. And the middle ring constitutes the group of people we interact with regularly, with whom we have some things in common but often important differences, and with whom we must negotiate some form of shared existence. According to Dunbar, the maximum number of ties we tend to have in this category is 150. The “closest proxy” for these middle ring ties, according to Dunkleman? Our neighbors.

Dunkleman believes that largely because of the advent of smartphone technology and social media (among other shifts), it is now much easier and more convenient to connect with our inner ring ties and our outer ring ties—leaving the middle ring to languish. For, if Dunbar is correct, a human being has only so much bandwidth for connection. If—as the data Dunkleman presents seems to indicate—we’re turning up the volume on inner-ring ties (Facetiming with Grandma and texting our spouse or best friend hourly), and spending more time on outer-ring ties (chatting with fellow birdwatching enthusiasts from across the globe and keeping tabs on old high school acquaintances on Facebook), then something’s gotta give. And one such something has been the time and effort we spend interacting with our neighbors.

So what? Times change and so do social norms. As long as we’re all well and happy, then what’s the difference, right? Well, we’re not all well and happy, for starters. And neither is our democracy, the success of which rests upon our ability to negotiate difference and broker compromise—a skillset we are losing as we focus our social energies on the people we already know and love, on the one hand, and people we choose to interact with because of some form of shared interest or affinity, on the other. Our inner ring and outer ring ties are “thickening” at the expense of a “thinning” middle ring, says Dunkleman. And the middle ring is where democratic citizenship, mutual aid, and the negotiation of difference thrive.

Could our turn away from neighborliness and toward affinity-group socializing have outsized consequences? And might it be possible that subtle shifts toward reimagining and reinvesting in the middle ring contain a cure for what ails an America increasingly crippled by loneliness, despair, and political unraveling? These are the questions that animate my Project Reconnect challenge for the month of April, in which I’ve set the intention of initiating a face-to-face interaction with each of my twenty-four closest neighbors. I’m setting out to see exactly what “rhythms” and “routines” have kept me from engaging in neighborliness since I moved into this community a year ago, and what might change as I reinvest in my middle ring.