I was looking down through the grate as I walked past the Harriet Tubman memorial at 122nd and St. Nicholas, when I heard a big “Hello!” There in front of me was a smiling African American woman in her fifties, examining the carrot tops spilling out of my grocery bag. “What a beautiful plant!” she said. “I have a plant like this at home. People think it’s ugly, but you just have to take care of it. How did you choose this plant?”

“Because it looked healthy,” I said.

“Is it potted?” She peered into the paper bag, where she found my scarf hiding the bundle of carrots. I smiled, said something about plants, and walked away. I failed to tell her it was a carrot, and I failed to ask her about her plants. Worst of all, I failed to make a new friend in my neighborhood.

I’m an urban planner. As part of my job with MIT’s Community Innovators Lab, I spent four months interviewing residents of Brooklyn’s Bedford-Stuyvesant and Clinton Hill neighborhoods with the goal of understanding what gentrification means for the longstanding community, at a time when that community is being threatened by swanky glass-faced co-op buildings and hordes of new residents fleeing high Manhattan rents.

The night I ran away with my carrots, I re-listened to hours of audio recordings and found what I knew was already there: tape after tape of Bed-Stuy stalwarts lamenting that the new people moving into their neighborhood, specifically the new Caucasian people, were un-friendly. My interviews revealed that the arriving gentry didn’t say hello on the sidewalk, didn’t hold doors open, and didn’t try to meet their neighbors.

The personal connection was abysmally obvious: the woman I met at the Harriet Tubman statue could be one of these interviewees, and her anecdote could be about me. I went to bed feeling very, very white.

Bedford-Stuyvesant, commonly called Bed-Stuy, formed in 1930. It is a historically black community, one of many northern urban neighborhoods that became home to African Americans who left the South between the end of Reconstruction and the Civil Rights Movements.

Mr. James Grant, my oldest interviewee at age ninety-five, moved to the area from South Carolina in 1935. “Everybody was leaving then,” he said, “coming to New York. You could make a lot of money. At that time, you weren’t making anything in South Carolina, or any of those states.” This generation of African Americans, as they moved north, was only 70 years older than the Civil War.

Ms. Inez Pitman, age seventy-five, moved to New York from Alabama in 1950. She too brought a vibrant history. She remembers hiding in her mother’s bed, praying that her father would come home alive, while he was out organizing for desegregation. Ms. Pitman was nineteen when she moved to New York, where cousins welcomed her. She eventually got a job with the which union, served a full career, and is now retired. On nice days she sits on her front stoop and talks with her neighbors. A few years ago she noticed that the college students living next door to her were passing her by. “Don’t walk by me and don’t say hello!” she said to them. “I’m sitting here! I’m somebody! Say hello!” The students began to say hello.

Ms. Catherine Arline, who came to Bed-Stuy in 1953, remembers a constant flow of neighbors at her mother’s stoop in North Carolina, seeking help and advice. It was this experience that inspired her to become a social worker. Ms. Arline was only sixteen years old when she came to New York. She found a position as a housekeeper, a job she returned to every summer until she finished high school. She used her earnings to support her sister’s college tuition. “I loved Brooklyn because there was a southern peace to it I had known.”

Many of the subsequent generation did not know that southern peace, as they were born and raised in the city. Rachel Spivey, born in 1957, has only ever called Brooklyn home. She recalls a wholesome childhood on Washington Avenue, where everyone’s mother and father kept an eye on everyone else’s children. She still reunites with her grade-school classmates each August in P.S. 11 park. But it’s a different neighborhood now. Parents don’t watch one another’s children, and the people she passes on her childhood streets now don’t say hello. “How can you want to live in the neighborhood with me, but you really don’t want to live with me? Because living with me would mean, to me, interacting with me. Not to say that you have to interact with me, but can’t we just say hello and goodbye and smile at one another? Because it brings about a different feeling about the neighborhood when we don’t do it like that.”

Christopher Bloodworth, also raised in Bed-Stuy, but in his mid-20s (like me), sees the same changes. “One of the things I’ve always known about growing up in Bed-Stuy, is that you know your neighbors and you speak to your neighbors, ‘Hey, how are you doing?’ and different things like that.” Some of the new residents on Bloodworth’s block greet him with silence every day. “It’s very frustrating to know,” said Bloodworth, “that somehow Ralph Ellison’s words still ring true, that you can still be invisible.”

When Bloodworth was a child, the woman renting the apartment above his was a long-term tenant who watched him grow up and talked with him on the stairway. She was like a second mother to him. Today, as a property-owner and landlord in Bed-Stuy, Bloodworth maintains stable rents despite the profits he could reap as neighborhood rents rise. His priority is to keep tenants for the long-term, as his parents did.

Once the norm, Bloodworth is an anomaly in the new central Brooklyn. Gentrification, as it works its way down Myrtle Avenue and the neighborhood’s other prominent streets, brings visually satisfying things, like quaint storefronts and clean sidewalks. Real estate developers tout an “up and coming” neighborhood. Houses that were once securely in Bed-Stuy are now advertised as Clinton Hill, since the latter is more fashionable. New glass-faced buildings are windows into a life that many long-time Brooklynites cannot afford. Gentrification is made to look and feel like a Renaissance. But under the surface of new glass walls, New York is experiencing something much less innovative than a rebirth.

Gentrification is a re-shuffling. It’s part of a relentless American history of moving populations en masse from one location to another when their presence becomes inconvenient. This country moved Native Americans out, and brought slaves in. In more recent history, it drew middle class people to the suburbs, and redlined African Americans into urban ghettos. It tore down and displaced whole neighborhoods with Urban Renewal in the 1950s and 60s. Hope VI, the most recent iteration in American housing policy, was meant to build mixed-income communities, but in practice displaced thousands of low-income people from functional homes and neighborhoods. Gentrification, in many ways, feels like a new name for an old game. At least we now have a multi-racial gentry class.

In my twenty interviews, one wish came through stronger than friendliness. People want diverse neighborhoods, including different races, ages, and sexual orientations, with an array of careers, representing different socioeconomic classes. Brooklyn native Tyrone Harris said, “The diversity in the neighborhood is so good, that we can learn about the whole world in just one neighborhood, because we have Chinese, African American, Latino, and White. We have everything here. Puerto Rican, Spanish—you name it, we got it. But the thing is, are we using our assets? Or are we just sitting back saying, ‘We don’t like this or we don’t like that.’ See, it’s easy to complain, but the question is: What do you want to do?”

I thought that if I could change my behavior and say hello, that some small but important change would take place. I wanted to write this article telling other people like me, white folks living in historically black neighborhoods, that they needed to get to know their neighbors. Maybe friendliness would lead to people learning some of the history I learned, and maybe that would spur the kind of mutual understanding that characterizes unified communities.

But saying hello, of course, doesn’t un-displace people who can no longer afford their homes. Affordable housing does the work of un-displacing people. Good policies create stabilized neighborhoods. Funds that support community institutions, such as churches and arts centers, facilitate local networks.

Saying hello is good, but it’s acting within a given structure. The bigger battle is to fight for better structures, which isn’t a one-person battle.

“We want a neighborhood where we are all together,” said Ms. Pitman. “You want the people to get together. Some people don’t care if they pass by, but I’m not that type of person.”