Why the sounds of eating make some people so angry

Nobody likes hearing someone crunching their food, but for some it’s more than just an annoyance — the sound triggers a full “fight or flight response.” These people have a rare condition called “misophonia” that makes them extraordinarily sensitive to everyday sounds, and new research confirms that their brains really are wired differently.

For a study published this week in the journal Current Biology scientists scanned the brains of 20 people with misophonia and 22 without. All participants listened to unpleasant sounds including screaming, neutral sounds like rain, and what people considered their “trigger” sounds, like certain eating or breathing sounds. Nobody enjoyed the annoying sounds. But when people with misophonia heard their trigger noises, they started sweating and their heart rates went up.

By looking at the brain scans, the researchers saw that the wiring between different regions of the brain is different in people who react that strongly. One region of our brain is called the anterior insular cortex and it influences what we pay attention to. For people with misophonia, that region was more active when they listened to trigger sounds. Not only that, but their AIC connected a lot more to other regions, which also contributed to the extreme response.

Misophonia is pretty rare, but knowing more about how the brain creates this emotional response could help us develop better treatments for it — and maybe also help the rest of us who don’t have the condition but still want to shudder when we hear loud breathing.