Chronic Bias Is Hardwired

In partisan issues, which are most issues, the mind judges “our side” and “their side” in wholly different ways.

At last, hard data confirm the stubborn trait. Physical science can now see the biased brain doing its dark deeds. We watch it simply sidetrack anything that helps an opposing view.

A study at Emory University shows how the biased brain physically throws away annoying evidence. This revelation may help or not. Still, the contortions of the reflex that trashes evidence are worth knowing.

In the early 17th century, the telescope let sky watchers see deeper into the heavens. The new tool brought swift discoveries of the truths about our solar system. 

The tool we use to see a biased mind at work is functional magnetic resonance imaging, or fMRI for short. This ingenious device can look at each separate part of a brain, and know at each instant if the part is active or idle.

Happily, the only probes fMRI needs are invisible forces, not wires. It has to do with blood flow in busy parts of the brain that is detected by magnetic differences between blood with more or less oxygen in it.

Ah, the wonders we devise.

The next piece in the story is using fMRI to map the brain. The mapping tells which sites in the brain are activated for specific purposes. A purpose might be tied to sights, sounds, moving the fingers, handling language, sorting out clues, booing in disgust, or laughing with glee.

With the powers of fMRI, a modern brain map is remarkably exact.

So we have a map of the brain and a tool that sees which parts are busy. Now for the search inside.

The researchers studied a sampling of committed Democrats and Republicans during three months before the presidential election of 2004. The brain functions of each partisan were probed by fMRI while he or she read a series of statements in pairs. Six pairs of statements were from President George Bush, six from his opponent Senator John Kerry, and six from a politically neutral figure, such as actor Tom Hanks.

Each pair of statements was chosen to show a clear contradiction between the figure’s words and deeds, implying the person was lying or pandering. Each partisan was asked to consider the discrepancy and rate the extent to which the party nominee was devious.

Then each partisan was given a statement that might explain away the discrepancy. Each was asked to reconsider and again rate who was slippery and who was straight.

Can you guess the gyrations in the partisans’ minds that were seen by fMRI?

In starkest terms, information that threatens a partisan’s avowed stance is simply not processed. “Not processed” means “routed to bypass the parts of the brain that reason.”

In detail, the brain of its own accord routes news we scorn to the brain sites known to boo, hiss and laugh, and it avoids sites able to analyze, reason or judge.

Think of it. The logical sites are never sent the data.

As a result, partisans’ minds easily saw the contradictions in the despised candidate. The same failings in their prized candidate were invisible. Democrat and Republican minds mirror the same bizarre action. All minds worked alike on Tom Hanks.

We see the trait because fMRI shows strong blood flow in the emotion sites and quiet flow in the analysis parts. The brain at work—its need for oxygen and blood flow in busy part—is physically measurable.

Science discloses the dark truth: Once a mind sets its political course, it autorejects facts that weigh for the other side. Bias is hardwired. Evolution suffers the blame.

Doubtless other interests, say the environment, battle the same trait. It runs in all camps, both ours and the scurvy ones.