Want to see airline passengers do a great impression of the Hulk? Parade the economy passengers through first class before a long flight.

In a study published Monday, researchers found two big factors that increased the likelihood of air rage incidents: Whether or not there was a first class cabin on board, and whether or not economy passengers had to pass through it during boarding.

"Air rage in economy is much more common when that plane has a first class cabin than when it does not," the study's lead author, Katherine DeCelles, told Mashable.

How much more common? A whopping 400 percent.

So salty I actually mumbled "must be nice" to a lady while I was walking through first class and the air hostess handed her champagne. — Zara Smith (@zoopyzee) March 28, 2016

I always fart while walking through first class. — Steve Kramer (@kramerss) March 3, 2016

They did us dirty walking us through first class knowing damn well we are at the back of the plane 😂 — JuelzSantana☽ (@JFL0REZ) January 14, 2016

The study, by DeCelles, who is an associate professor at the University of Toronto, and Michael Norton of Harvard Business School, analyzed thousands of flights on a large international airline over several years and found that not only were incidents in economy more likely if there was a first class cabin, and more so if economy passengers had to walk through it — but incidents were also more likely in first class itself.

In other words, class inequality stresses everyone out, the study found.



"Physical design that highlights inequality can trigger antisocial behavior on airplanes," the researchers wrote.

The "antisocial behavior" they're referring to includes the types of behavior in the many, many incidents that have made headlines as of late, like when a woman threw a glass of water on a passenger when he prevented her seat from reclining, or when two women brawled mid-flight because of a crying baby, or when a grown man choked another passenger after she reclined her seat, or — you get the picture.

These incidents frequently result in flight diversions and the involvement of law enforcement, which are costly for airlines and inconvenient for everyone else on board.

It's worth noting that while the study found statistically significant correlations between in-flight inequality measures and air rage incidents, that does not necessarily mean that the manifestations of inequality are causing the incidents. Also, the study is limited to one airline’s data, and it’s possible that broader surveys might show more subtle relationships, if any.



DeCelles' previous research focuses on organizational behavior and criminology: "I'm interested in inequality and people's reactions to unfairness," she said.

In studying incidents on the international airline, which provided the data on the condition of anonymity, DeCelles found that air rage incidents contain parallels to the relationship between inequality in living situations and crime rates.

"The modern airplane reflects a social microcosm of class-based society."

"The modern airplane reflects a social microcosm of class-based society," the study says, "making inequality salient to passengers through both the physical design of the plane (the presence of a first class cabin) and, more subtly, boarding procedure (whether economy passengers must pass through the first class cabin)."

An airplane, then, is a real life representation of wealth inequality that most people usually only experience in the abstract. It's like feeling just fine about your five-year-old Toyota Corolla — until a brand new Porsche cuts you off on the highway.

And even though passengers are only briefly exposed to in-flight inequality when passing through first class, that exposure seems to be having a very negative effect.

From the study's authors:

We suggest that physical and situational inequality are built into people's everyday environments — such as the modern airplane — and that exposure to these forms of inequality can trigger antisocial behavior. Analyses reveal that air rage is more common in economy class on airplanes, where inequality is physically present, and in both economy and first class when inequality is situationally salient.

Modern commercial airline conditions like shrinking economy seats and packed flights are of course not blameless for mid-air misbehavior, but the study highlights the ability of reminders of inequality to escalate the situation.

What's more, the study's authors looked at seat pitch — the standard measure for airplane seat size — and found no correlation with air rage incidents. So even though those cramped seats are causing you discomfort, DeCelles says they aren't necessarily causing violence, at least on the airline in the study.

The study also found a difference in the types of antisocial behavior most common in first class compared to economy.

In first class, the researchers wrote, incidents "were more likely to be a result of belligerent behavior, involving a passenger's expression of strong anger," while incidents in economy "were more likely to result from emotional outbursts" ostensibly caused by the feeling of having no control.

First class passengers get angry. Economy passengers lose control.

That's consistent with previous sociological research on how relatively advantaged and disadvantaged people respond to situations they deem unacceptable: To generalize, first class passengers get angry. Economy passengers lose control.

If mid-air fights are something you'd like to avoid, the research is not comforting.

"Class-based seating is both more prevalent and more unequal in recent years, with first class cabins claiming an increasingly large share of total space," the researchers wrote. And what they left unwritten: First class is only getting better, while economy on many airlines is getting worse.

A Thousand Pardons From a Guy Walking Through First Class to Get to Seat 32B: https://t.co/wcTaNrBoIP pic.twitter.com/CCbKnhbgYg — Timothy McSweeney (@mcsweeneys) April 18, 2016

DeCelles did offer some suggestions for reducing incidents, however. For one, when possible, airlines should board first and economy classes through separate doors. Unfortunately, that requires not only aircraft with appropriate doors, but also airports with gates that support separate entrances.

But there are other things airlines can do: Decrease the in-your-face inequality by not openly favoring first class passengers, and not constantly reminding economy passengers that no, that lavatory at the front of the plane is not for them.

And having a nice economy cabin — DeCelles noted the economy seats on JetBlue's new aircraft with the Mint first class section — can also keep passengers happy.

"People know that inequality is going to happen," she said. "They just don't want to be treated like dirt."

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