… or at least that’s the case according to researchers at CalTech, who’ve been using fMRI to examine how the human brain responds to rewards [via Freakonomics; image by jsmjr].

… what was unknown was just how hardwired that dislike really is. “In this study, we’re starting to get an idea of where this inequality aversion comes from,” he says. “It’s not just the application of a social rule or convention; there’s really something about the basic processing of rewards in the brain that reflects these considerations.”

The brain processes “rewards”—things like food, money, and even pleasant music, which create positive responses in the body—in areas such as the ventromedial prefrontal cortex (VMPFC) and ventral striatum.

Procedural and methodological stuff follows, so let’s skip to the kicker:

As it turned out, the way the volunteers—or, to be more precise, the reward centers in the volunteers’ brains—reacted to the various scenarios depended strongly upon whether they started the experiment with a financial advantage over their peers.

“People who started out poor had a stronger brain reaction to things that gave them money, and essentially no reaction to money going to another person,” Camerer says. “By itself, that wasn’t too surprising.”

What was surprising was the other side of the coin. “In the experiment, people who started out rich had a stronger reaction to other people getting money than to themselves getting money,” Camerer explains. “In other words, their brains liked it when others got money more than they liked it when they themselves got money.”

“We now know that these areas are not just self-interested,” adds O’Doherty. “They don’t exclusively respond to the rewards that one gets as an individual, but also respond to the prospect of other individuals obtaining a reward.”

That’s a lovely interpretation that I’d dearly love to believe in, and I have not even a fraction of the medical knowledge I’d need in order to attempt to refute it, nor refute the way the research was framed.

So instead I’ll pose a question: if we’re so hardwired to loathe income inequality, and those starting with greater fortunes are supposed to enjoy seeing others rewarded more than themselves, why exactly is income inequality such a widespread feature of almost every culture on the planet?