Sen. Rand Paul sustained five broken ribs after an assault by a neighbor last weekend. The alleged assailant, Rene Boucher, released a statement through his lawyer calling the incident “a very regrettable dispute between two neighbors over a matter that most people would regard as trivial.”

People familiar with the situation have told reporters that a disagreement over yard waste may be to blame. A resident of the gated community where the assault happened told the New York Times that “if you can afford to live out here, you tend to your own business.”

Tending exclusively to your own business, it seems, is the preference of more and more Americans these days.

In 2016, the share of Americans who say they “never” socialize with their neighbors hit an all-time high of 34 percent, according to the General Social Survey. That number's been rising steadily since 1974, when just 21 percent said they never hang out with their neighbors.

The communities we choose to live in play a significant role in how much we interact with our neighbors. You might expect that densely populated cities foster neighborly friendships, but in fact the opposite appears to be true: People living in cities are the most likely to avoid spending time with their neighbors completely, while those in small towns and rural areas are the least likely.

We often think of cities as fertile grounds for social interactions between neighbors and acquaintances who spontaneously bump into one another on the street, sharing news, gossip and camaraderie. But the numbers above suggest that a sizable portion of city-dwellers are determined to avoid interacting with the people who live nearby — or, perhaps, that the circumstances of their lives are so hectic as to forestall most neighborly interaction.

Still, compared with 40 years ago, neighborliness is waning in small towns just as much as it is in big cities. There are a lot of different factors driving this trend, as outlined in a 2015 City Observatory report. We spend more time indoors, watching TV. The wealthy have walled themselves off in gated communities like the one Rand Paul lives in. “Space and experiences became more private, fueled by suburban expansion, large lots, and the predominance of single-family homes,” the City Observatory's authors write.

Trust is declining, too. The General Social Survey's data shows that the share of Americans saying most people can be trusted has fallen from nearly 50 percent in the 1970s to just over 30 percent today.

That lack of trust extends to our neighbors: In 2016 nearly half of Americans told the Pew Research Center that they trust only “some” or “none” of their neighbors. Mirroring the numbers on social interactions above, the survey found that people in rural areas were most trusting of their neighbors, while those in urban areas trusted their neighbors the least.

These trends may be self-reinforcing: We trust our neighbors less because we're interacting less frequently with them, and we're interacting less frequently with them because we trust them less.

“Good fences make good neighbours,” Robert Frost's neighbor said in his 1914 poem “Mending Wall.” For more and more Americans, it seems, the best neighbor is one you don't have to interact with at all.