Rush Limbaugh, Listen to Your Brain

Sam Pizzigati

Deep down in our lobes, says new research from an international scientific team, sits a basic tilt toward fairness.

Nature cover

Are we humans hard-wired to hoard or to “share the wealth”? Are we selfish by nature? Or do our psyches have a preference for equality built-in, right in our brains?

An international team of scientists, from Rutgers and Caltech in the United States and Trinity College in Ireland, has an answer for us. This scholarly team has just published in the British journal Nature the results from the first-ever experiments designed to show how our brains react to inequality.

Why should we care about how our brains, deep down in our lobes, feel about maldistributions of income and wealth? Such information, note the authors of this new brain research, could help us better understand the evidence from years of behavioral and anthropological studies.

We know from these studies, authors Elizabeth Tricomi, Antonio Rangel, Colin Camerer, and John O’Doherty point out, that people essentially “like transfers that reduce inequality.” But we don’t know why. Do human beings have a basic aversion to inequality or do we simply not want to look greedy to other people? Do we dislike the core unfairness of unequal distributions or do we worry that we ourselves might get the short end of the stick?

The field studies we have can’t answer these questions. Our brains waves can. MRI machines — those 3-D hospital scanners — can actually show how positively our brains are reacting to various situations. The new Nature study uses this MRI capacity “to test directly for the existence of inequality-averse social preferences in the human brain.”

The testing revolved around a simple experiment. The investigators assembled 20 pairs of previously unacquainted men, gave each man $30 in base pay, and had everyone choose a ball out a hat. In each pair, one participant would get a “rich” ball worth a $50 bonus, the other a “poor” ball that brought no bonus at all.

The researchers then proceeded to give each participant additional money, in varying sums up to $50 — and asked the participants to rate, on a ten-point scale, how appealing or unappealing they considered each of these additional distributions to be.

Meanwhile, with all this going on, the researchers were conducting MRI scans to see how the brains of the participants — specifically those parts of the brain that activate when we experience pleasurable rewards — were reacting.

What did the researchers find? The brains of the participants essentially lit up when an additional distribution narrowed the dollar divide between them. The “poorer” participants, no surprise, reacted positively when they received a greater additional distribution than the “richer” participants.

But the “richer” participants also reacted favorably, at the lobe level, when an additional distribution gave their “poorer” counterparts more money. In effect, the researchers note, “the high-pay group seemed to value transfers that closed the gap between their earnings and those of the low-pay group.”

The most intriguing finding of all: Some of the “richer” group, when asked to rate how appealing they found an additional distribution, gave distributions that privileged the “poorer” participants at their expense an “unappealing” rating. But the neural responses of these “richer” participants to these distributions told a completely different story. Their brains were actually cheering.  

The “basic reward structures in the brain,” the researchers observe, “may reflect even stronger equity considerations than are necessarily expressed or acted on at the behavioral level.”

The basic takeaway from the research? Conclude the investigators: “Our results provide direct neurobiological evidence in support of the existence of inequality-averse social preferences in the human brain.”

Or, in other words, down deep even Rush Limbaugh wants to share the wealth.

Sam Pizzigati edits Too Much, the online newsletter on excess and inequality published by the Washington, D.C.-based Institute for Policy Studies. Too Much appears weekly. Read the current issue or sign up to receive Too Much in your inbox.

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