Story highlights The presence of first-class seating was more associated with aggression than small seats and delayed flights

Experts caution that other factors could increase the risk of air rage on flights with first-class sections

(CNN) What is it about air travel that brings out the worst in us? We squabble for space in the overhead compartment and on the armrest. Some passengers have even been caught kicking each other and screaming at the flight crew, as YouTube videos bear witness.

A new study suggests an unexpected trigger for these rare cases of air rage. It found that passengers in economy seating were 3.84 times more likely to have an incident of air rage if they were on a plane that had a first-class section. They were 2.18 times more likely to have an outburst if they had to walk through first class to board the plane, as opposed to boarding in the middle of the plane, directly into the economy section.

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"Psychology (research) tells us that when people feel a sense of deprivation and inequality, they are more likely to act out," said Katherine A. DeCelles, associate professor of organizational behavior at the University of Toronto. DeCelles is the lead author of the study, which was published on Monday in the journal Proceedings of the National Academy of Sciences

Passengers are probably not even consciously aware of the deprivation and inequality, and how much it is stressing them out, DeCelles said. However, she and her colleague were not able to talk with the enraged passengers to get a better idea what set them off.

There was also a nearly 12-fold increase in the rate of air rage among first-class passengers on flights where all passengers boarded through the first-class section, compared with flights that had separate entrances for first class and economy.

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