My neighbors have two young children, and it seems like every time I visit, the kids have learned a dozen new words that they’re eager to show off. I ran into them the other day, and I found out that one of the new words their youngest child had acquired was a particularly heinous curse word (a synonym for fornicate), which she had learned after hearing her dad direct it toward a cabbie who had cut him off while driving in downtown Chicago. That story is probably familiar to anyone who has spent time with young kids: they learn new words with ease, but they seem to learn swear words especially quickly. There’s a lot of evidence that our brains are hard-wired to acquire language, but could it be possible that swear words are processed differently than other kinds of language?
As it turns out, there is a body of research on the neurobiology of swearing, and it largely supports the idea that the brain treats curse words as special. One source of evidence comes from Tourette’s syndrome (TS), a neurological condition characterized by involuntary behavioral tics. In some TS cases, these tics are manifested as involuntary outbursts of cursing or other inappropriate language. Another line of evidence is seen in aphasia, which is a specific loss of language caused by brain damage or dementia. Though people with aphasia may have severely impaired speech, they often produce curse words with greater fluency and regularity than other words.
In both TS and aphasia, we see examples of the brain treating swear words as a special type of language. But, why is swearing affected differently by each disorder? Scientists think that TS is caused by malfunctions in the basal ganglia, which are sets of structures deep in the brain that are responsible for inhibiting unwanted or inappropriate behaviors. In contrast, aphasia usually results from a stroke affecting the front part of the left hemisphere – the basal ganglia and other deep brain regions are often left intact. This distinction in underlying causes is why people with TS have trouble suppressing involuntary cursing, whereas people with aphasia have trouble initiating speech that isn’t cursing.
What makes swear words special in the first place? Finding a brain system mutually affected by both TS and aphasia is a key to answering that question. In this case, the common ground is the limbic system, a collection of deep brain regions which are responsible for processing emotions, certain automatic drives and habits, and even aspects of learning. Swearing has an undeniable emotional component – some scientists argue that swearing is more about expressing an emotional state than articulating an actual linguistic idea. In the same vein, cursing is also considered a kind of automatic speech, as it is often used to fill space between thoughts or ideas. And both the emotional and automatic aspects of swear words make them especially salient to language learners of all ages, not just children. For instance, people learning a second language often acquire curse words before other common words and phrases.
So in the end, swearing does appear to have a special place in the brain, which helps explain why kids pick it up so easily, why people with TS sometimes can’t control it, and why people with aphasia are often better at it than they are at producing other language. The fact that these patterns are consistently found in different languages – including sign languages! – further supports this idea. I don’t think this should be taken as a license to go out and paint the air blue, of course: swear words are still universally considered to be taboo. But hopefully, the next time you hear a little boy gleefully share his new favorite curse word, you’ll appreciate that his brain treats that word differently than other words, and that he probably has no idea what the word means apart from its emotional value.