" A final depressing point about inequality and violence. As we’ve seen, a rat being shocked activates a stress response. But a rat being shocked who can then bite the hell out of another rat has less of a stress response. Likewise with baboons—if you are low ranking, a reliable way to reduce glucocorticoid secretion is to displace aggression onto those even lower in the pecking order. It’s something similar here—despite the conservative nightmare of class warfare, of the poor rising up to slaughter the wealthy, when inequality fuels violence, it is mostly the poor preying on the poor. This point is made with a great metaphor for the consequences of societal inequality.41 The frequency of “air rage”—a passenger majorly, disruptively, dangerously losing it over something on a flight—has been increasing. Turns out there’s a substantial predictor of it: if the plane has a first-class section, there’s almost a fourfold increase in the odds of a coach passenger having air rage. Force coach passengers to walk through first class when boarding, and you more than double the chances further. Nothing like starting a flight by being reminded of where you fit into the class hierarchy. And completing the parallel with violent crime, when air rage is boosted in coach by reminders of inequality, the result is not a crazed coach passenger sprinting into first class to shout Marxist slogans. It’s the guy being awful to the old woman sitting next to him, or to the flight attendant.* "

― Robert M. Sapolsky , Behave: The Biology of Humans at Our Best and Worst