Hours before the carnage in Paris on Friday, a double suicide bombing ripped through a working-class shopping district in Beirut. ISIS claimed responsibility for the explosions, which caused 43 deaths and hundreds of casualties in the worst bombing to strike the city in a quarter century. Then came ISIS’s attacks in France, which quickly subsumed much of the attention that might have been directed toward Lebanon.

It’s become a predictable pattern: One act of violence in the world overshadows a similar, concurrent violent act, inviting a backlash against this imbalance in scrutiny, sympathy, and grief. But that predictability doesn’t make the pattern any less distressing. Each time there’s a major terror attack in an American or European city—New York, Madrid, London, Paris, Paris again—it captures the attention and concern of Americans and Europeans in a way that similar atrocities elsewhere don’t seem to do. Seldom do events line up so neatly, offering a clear comparison, as the bombings in Beirut and the rampage in Paris.

Viral articles on Facebook are demanding to know why the Beirut attacks have been overlooked. Lebanese have lamented the discrepancy. Many people are asking why Facebook didn’t allow people in Lebanon to check in as “safe” on the social network, as the company did for those in Paris.

So what exactly accounts for this apparent gap in empathy?

One potential explanation is simple: There were three times more deaths in Paris than in Beirut. Beyond that are a host of other, intertwined reasons. Perhaps chief among them is familiarity. Americans are much more likely to have been to Paris than to Beirut—or to Cairo, or to Nairobi, or to any number of cities that have experienced bloody attacks. If they haven’t traveled to the French capital themselves, they’ve likely seen a hundred movies and TV shows that take place there, and can reel off the names of landmarks. Paris in particular is a symbol of a sort of high culture. Just as a mishap in your hometown hits harder than one two towns over, the average American is likely to relate more closely to violence in Paris than in other parts of the world. There is also a troubling tribal, or racial, component to this familiarity factor as well: People tend to perk up when they see themselves in the victims.

Closely related is a divergence in expectations. In January, Matt Schiavenza argued perceptively in The Atlantic that one striking difference between the Charlie Hebdo massacre in Paris and a roughly contemporary suicide bombing by a 10-year-old in Nigeria was that France is not a country with a failing government or chronic conflict. As a result, attacks there are more shocking.

Many Americans hear “Paris” and think of the Eiffel Tower; they hear “Beirut” and immediately associate it with war. Yet that’s an outdated impression, as The New York Times reported: “While Beirut was once synonymous with violence, when it went through a grinding civil war a generation ago, this was the deadliest suicide bombing to hit the city since that conflict ended in 1990. ... [I]t had been a year of relative calm.”

Beirut, in fact, was once known as the Paris of the Middle East. And while that name is no longer in common usage, there are still similarities between the cities. In the centers, prosperous neighborhoods offer fine dining and glamorous shopping. Farther out, less wealthy residents—many of them immigrants or children of immigrants—live in working-class districts. Paris’s suburban districts, known as banlieues, are heavily populated by Muslim immigrants. “Parisians and tourists rarely visit them, and residents complain that journalists drop in only to report on car burnings and drug shootings,” George Packer recently reported in The New Yorker. “Many suburban residents, meanwhile, never even think of going to Paris.” In Beirut, there are neighborhoods like Bourj al-Barajneh, a suburban, working-class district where the population consists of many Lebanese Shiite Muslims, plus Palestinian refugees and the most recent arrivals, Syrian refugees. It was the Shiites there whom ISIS, a Sunni Muslim extremist group, was targeting last week.

Nor is Paris quite as calm as Americans might imagine. For example: Riots of considerable size are roughly a yearly event, especially in the banlieues; in 2005, during some of the largest riots in recent memory, three people were killed in violence triggered by police chasing three boys, but clearly emblematic of deeper tensions. This may not be the Paris that many Americans think of, but it is Paris just the same. (Both Paris and Beirut even suffered serious garbage-collection strikes this year.)

Or should the empathy gap be attributed to an American and European press that focuses too heavily on attacks in the “West”? It’s far easier to get reporters to Paris than, say, Nairobi, though the critique is unfair to the brave reporters who report from dangerous parts of the globe year-round, not just when violence erupts. It’s a good bet that if American news organizations had devoted every resource that they dedicated to the Paris attacks to the bloodshed in Beirut instead, readers, watchers, and listeners wouldn’t have paid nearly the same amount of attention.

In part, this dynamic is an outgrowth of the familiarity and expectations gaps. In an article for The Atlantic last year, Jacoba Urist reported on the findings of a study of natural disasters around the world, which found that the level of American media attention correlated with geographic proximity to the U.S. and the number of American tourists who had visited the country in question. (Urist noted that a 1976 Guatemalan earthquake with 4,000 fatalities accrued a third of the media coverage of an Italian earthquake with 1,000 deaths.) And as Faine Greenwood suggested after the Charlie Hebdo attacks, journalists and their audience alike suffer from a novelty bias. If it isn’t new—a new attack, a new place—it won’t garner the same buzz.

There are coldly economic rationales in play, too. What about Facebook? Founder Mark Zuckerberg has said the only reason there was no safety check-in for Beirut was that Facebook decided only after the Paris attack to deploy the feature for non-natural disasters. That aside, it makes sense that Facebook would move faster on Paris. After all, there are twice as many people in the Paris urban area as there are in all of Lebanon. Even assuming 100-percent Facebook penetration in Lebanon (not far off, probably), there are simply more Facebook users in Paris for the company to respond to.

Whatever the drivers of the empathy gap, the gap itself has real consequences. Following the attacks, U.S. Senator Lindsey Graham said, “This is not just an attack on the French people, it is an attack on human decency and all things that we hold dear.” The statement was eloquent and true, but as Ishaan Tharoor of The Washington Post noted, American politicians issued few equivalent statements about Beirut. If no one points out that suicide bombings in Beirut are no less an attack on human decency than those in Paris, it is much easier to sort the world into a clash of civilizations—where innocent deaths on one side are more deserving of mourning than innocent deaths on the other.