The story of how Americans came to peer beyond their own properties is also, inescapably, about race. As urbanization brought blacks and whites closer together, white communities reacted with racially restrictive covenants, aiming to keep blacks and their perceived threat to property values out of white neighborhoods. The Supreme Court ruled such covenants unenforceable in 1948, but they had long-lasting effects on how homeowners looked at the world around them, and the need to control it.

“One of them was to make white people think that the value of their homes depended on living in a segregated community,” said Carol Rose, a law professor at Yale. “That outlived racially restrictive covenants.”

Another shift came with the advent of citywide zoning in New York City in 1916. Nuisance laws had targeted problems like noxious odors or chemical spills that crept across property lines. Zoning, rather than punishing people for proven harms that came from their property, told people what they could do on their property in the first place. And it prohibited many things — like buildings of a certain height — that had never been considered nuisances before.

Zoning effectively invited homeowners to look beyond their properties in ways they hadn’t. And it helped create the expectation that communities would change little over time — or that homeowners would have a say if they did.

“Prior to zoning, you didn’t ask yourself if you were buying a piece of property, ‘What’s the use of the land next to me, or down the block, or half a mile away?’ ” said William Fischel, an economist at Dartmouth. “Zoning becomes an opportunity for you to think outside the box of the lot lines of your own property. And people definitely start doing it.”

Americans fretted about property values in the early 20th century (and government documents at the time warned of how racial integration would harm them). But Americans didn’t broadly begin to think of homeownership as a means to create wealth until around the 1970s, when housing started to appreciate faster than many other assets. And once housing became a financial asset — the largest one many families own — homeowners began to take more seriously anything they feared would harm it, Mr. Fischel said.

“The mere possibility that a funeral home three blocks away might cause a funeral procession to go down a street just when a buyer’s there, these remote threats — almost imaginary threats — start to become more resonant,” Mr. Fischel said.