Disagreements seem to be an unavoidable part of life, occurring everywhere from comment sections to courtrooms. A new study from Yale researchers, published in Frontiers in Human Neuroscience, took a peek into people’s brains while they were discussing controversial topics. The results suggest that “it just takes a lot more brain real estate to disagree than to agree,” said lead author Dr Joy Hirsch in a statement. Dr Hirsch also explained that when two people are debating a topic, “There is a synchronicity between the brains when we agree, but when we disagree, the neural coupling disconnects.”
The study involved 38 adults, who filled out a survey on whether they agreed or disagreed with four topics surrounded by controversy. The spicy statements were: “video games are a waste of time,” “the death penalty should be banned,” “same-sex marriage is a civil right,” and “marijuana should be legalized.” The people were then put into pairs – or “dyads” – where they agreed on two of the topics and disagreed on the two others, then engaged in a face-to-face debate on the topics. During the debates, their brains were observed using functional near-infrared spectroscopy, and their speech was analyzed.
Brain activity was revealed to be significantly different during agreement and disagreement. When the pair agreed on the topic at hand, social and visual brain activity was more synchronized and harmonious. The activity of the brain was focused on social and attention networks in areas like the bilateral frontal eye-fields, left frontopolar regions, and the right supramarginal gyrus. This is most likely in response to social cues. This, according to Dr Hirsch, “is less cognitive engagement and more social interaction between brains of the talkers, similar to a musical duet.”
During a disagreement, however, brain activity between the pair was more discordant, “like a symphony orchestra playing different music” as Dr Hirsch puts it. Sensory areas were less active, whilst areas involved with higher cognitive functions were fired up. These included areas in the frontoparietal system: the angular gyrus, superior temporal gyrus, left supramarginal gyrus, and the bilateral dorsolateral prefrontal cortex. Speech analysis also showed that syllable rate and acoustic energy were elevated during disagreements, which will strike a chord with anyone who has been shouted over during a heated argument.
The research showed that the “dyad” acted as a social unit, with spoken information and social cues linking individuals together. In the paper, the researchers noted that “The relevance of insight regarding the neurobiology of human dyadic behavior during expressions of congruent and incongruent opinions is highlighted in times of extreme political and social division.”