Disagreeing takes up a lot of brain space

Yale researchers have come up with a way to look inside the brains of two people at the same time while they are arguing. What they found should come as no surprise to anyone who has argued over politics or social issues.

When two people agree, their brains display a calm synchronicity of activity targeting sensory areas of the brain. When they disagree, however, many other parts of the brain involved in higher cognitive functions are mobilized as each individual fights the other’s argument, a Yale-led research team reports Jan. 13 in the journal. Frontiers of Human Neuroscience.

“Our entire brain is a social processing network,” said senior author Joy Hirsch, the Elizabeth Mears and House Jameson professor of psychiatry and professor of comparative medicine and neuroscience. “However, it takes a lot more brain space to disagree than to agree.”

For the study, researchers at Yale and University College London recruited 38 adults who were asked to say whether they agreed or disagreed with a series of statements such as’ same-sex marriage is a civil right ‘or’ marijuana should be legalized. After matching couples based on their responses, the researchers used an imaging technology called functional near-infrared spectroscopy to record their brain activity as they had face-to-face discussions.

If the people agreed, the brain activity was harmonious and mostly focused on sensory areas of the brain, such as the visual system, presumably in response to social cues from their partner. During disputes, however, these areas of the brain were less active. Meanwhile, activity increased in the brain’s frontal lobes, home to higher-order executive functions.

“There’s a synchronicity between the brain if we agree,” said Hirsch. “But if we don’t agree, the neural link will be broken.”

Understanding how our brains function while we disagree or agree is especially important in a polarized political environment, Hirsch noted.

In disagreement, she said, two brains use a lot of emotional and cognitive resources “like a symphony orchestra playing different music.” It has been agreed that there is “less cognitive involvement and more social interaction between the brains of the talkers, similar to a musical duet.”