Frankfurt argues, though, that we aren’t really bothered by inequality for its own sake. He points out that few worry about inequalities between the very rich and the very well off, even though these might be greater, both absolutely and proportionately, than inequalities between the moderately well-off and the poor. A world in which everyone suffered from horrible poverty would be a perfectly equal one, he says, but few would prefer that to the world in which we now live. Therefore, “equality” can’t be what we really value.

Some of Frankfurt’s arguments get technical, but it’s not hard to think of cases where a mistaken focus on equality makes the world worse. My favorite example here is from the comedian Louis C.K., where he describes how his five-year-old’s toy broke and she demanded that he break her sister’s toy, which would make things equal. “And I did. I was like crying. And I look at her. She’s got this creepy smile on her face.”

Can Frankfurt really be right that people don’t value economic equality for its own sake? Many scholars believe otherwise. The primatologist Frans de Waal sums up a popular view when he writes: “Robin Hood had it right. Humanity’s deepest wish is to spread the wealth.”

In support of de Waal, researchers have found that if you ask children to distribute items to strangers, they are strongly biased towards equal divisions, even in extreme situations. The psychologists Alex Shaw and Kristina Olson told children between the ages of six and eight about two boys, Dan and Mark, who had cleaned up their room and were to be rewarded with erasers—but there were five of them, so an even split was impossible. Children overwhelmingly reported that the experimenter should throw away the fifth eraser rather than establish an unequal division. They did so even if they could have given the eraser to Dan or Mark without the other one knowing, so they couldn’t have been worrying about eliciting anger or envy.

It might seem as though these responses reflect a burning desire for equality, but more likely they reflect a wish for fairness. It is only because Dan and Mark did the same work that they should get the same reward. And so when Shaw and Olson told the children “Dan did more work than Mark,” they were quite comfortable giving three to Dan and two to Mark. In other words, they were fine with inequality, so long as it was fair.

In research I’ve been involved with at Yale, led by then-graduate student Mark Sheskin, we find that younger children actually have an anti-equality bias—they prefer distributions where they get a relative advantage over equal distributions where everyone gets the same. For instance, children prefer one for them and zero for another child over an arrangement where everyone gets two.

This finding meshes well with what other psychologists have found—and which many parents have observed: When treats are being distributed, children will complain bitterly if they get less, but are entirely mellow if they get more. Other primates behave similarly. Monkeys enjoy cucumbers and will normally be happy getting one, but if they are handed one after having just seen another monkey getting a grape—which monkeys love—they freak out. The monkey with the grape, on the other hand, is perfectly comfortable with its relative advantage.