Linda Poon is a staff writer at CityLab covering science and urban technology, including smart cities and climate change. She previously covered global health and development for NPR’s Goats and Soda blog.
The researchers behind “Inequaligram” mined more than 7 million photos to distill how social media reflects inequalities in the city.
Inequality reveals itself in many different forms. You can look at income distribution, compare crime rates, or even study the density of trees in a given neighborhood to see proof. Now, two researchers from the Graduate Center at the City University of New York are studying inequality through the lens of social media, putting to good use the tens of millions of photos uploaded daily to Instagram.
From one of the researchers who brought us Selfiecity—an analysis of selfies across multiple cities—“Inequaligram” uses 7.5 million publicly shared and geotagged photos taken in Manhattan to determine an area’s “social-media inequality.” This is determined by several factors, including how much attention some neighborhoods get on platforms like Instagram and Facebook—and how little attention others do. The photos are divided into two groups: those taken by locals and those likely shared by tourists.
To calculate the social-media inequality of Manhattan, computer-science professor Lev Manovich and Agustin Indaco, an economics student, mapped how evenly distributed the photos were across the borough’s 287 Census tracts.
Their analysis shows that more than half of all visitors’ photos are concentrated in 24 tracts, which cover just 12 percent of Manhattan’s total area. Most of these photos were shared in Midtown, with some originating from downtown. Among photos posted by locals, half come from just 53 tracts, which cover a just about a fifth of the borough. In both maps, the upper parts of Manhattan have little to no social media presence.
The researchers also mapped the time the photos were taken, highlighting which areas remain popular during the day and at night:
When he looked specifically at how locals photograph Manhattan and compared the distribution to the average income level within each tract, Manovich found that less-affluent tracts (with median household incomes lower than those in Manhattan as a whole) are more popular at night, while more affluent tracts are busier during the day. The researchers offer one possible explanation for this pattern in their paper:
The residents of less prosperous areas (such as parts of Manhattan above 100th street) go to work in more prosperous parts of the city (especially Midtown Manhattan) during the day. This is where they share images on Instagram during the day, so their shares get added to these areas. Consequently, since they are absent from their home areas during these working hours, the volumes of images in these areas during daytime is small. In the evening, they return to their areas of residence, and this is why these less prosperous areas have higher volume of Instagram shares at evening and night hours.
Based on the overall distribution of photos, Manovich calculated the Gini index for the two sets—a step that will come in handy for comparing how social-media inequality changes over time, and how it compares among different cities. (The Gini index, which uses a scale from zero to 1, is the most common measure of a nation’s inequality. A score of zero indicates complete equality and a score of 1 means one person or one group holds all of an area’s wealth.) Among photos shared by locals, the Gini index is 0.49, and 0.67 for photos by tourists.
To understand those scores, the researchers compared them to the level of economic inequality found in different places. The first score, 0.49, is comparable to the overall national income inequality score of 0.41, which is considered high for a developed nation. The second score is higher than the inequality score for all of Manhattan—and Seychelle, the African country with one of the highest Gini-index scores in the world. Both sit at 0.66.
Manovich says he assumed the distribution would be fairly uneven among photos shared by locals, but was surprised by just how disproportionate it was. Overall, he writes in the study, the most-photographed square kilometer of space in Manhattan has 250,000 more photos than the least-photographed area. “I just didn’t expect [the difference] to be so large,” he tells CityLab.
Why does this all matter when researchers and urban planners have already demonstrated New York’s staggering inequalities through measurements like household income, lack of housing affordability, and sluggish wage growth?
By looking at social media as a measure of inequality, says Manovich, “it gives us a different way to think about cities.” The photos give an idea of how people feel about certain areas throughout a city, which can have real implications for both businesses and urban planners.
Looking at social media encourages a city to find the “optimum balance," he says. In a city where tourists have a real economic impact, you don’t want to have visitors crowded around just Midtown and the downtown areas, for example. “You’d want people to not just spend all their money on business in one place, and you don’t want a city to be known for just one small area,” he says. “So it has implications for how cities promote and advertise.”