Why your brain can’t stop swearing even after a stroke

The phrase “expletive deleted” once defined the boundaries of acceptable public discourse. Today, that standard has eroded significantly. During a July 29, 2026, Senate Homeland Security & Government Affairs Meeting, Senator Bernie Moreno (R-Ohio) directed a profanity-laced question at Dr. Anthony Fauci regarding a 2020 incident involving an Ohio mother arrested for refusing to wear a mask at a middle school football game. Moreno asked, “Here I’m sitting in front of you six years later saying, who the f*ck do you think you were for doing that?”

Neurological basis of swearing

Expletives are processed by different brain circuits than ordinary speech. They can become so automated and habitual that they defy vigorous efforts to suppress them. Neuroscientists have demonstrated through imaging studies that the brain circuits involved in Tourette’s syndrome and other repetitive uses of expletives include the basal ganglia, thalamus, motor areas, cingulate cortex, and prefrontal inhibitory system. When functioning normally, this circuit prevents the expletive from reaching vocal expression via the inhibitory effect of the prefrontal cortex.

Voluntary swearing involves a decision preceding the utterance, while involuntary swearing is more common and reveals underlying brain mechanisms. Coprolalia, the compulsion to speak expletives in the presence of others, involves an urge to shout out “bad words” competing against the simultaneous desire to suppress them. In Tourette syndrome, this inner tension can lead to a frenzied paralysis of will based on the simultaneous affirmation and negation of coprolalic words.

Impact of language damage

An expletive may survive neurologic damage that adversely impacts pathways responsible for normal everyday language. Thanks to specialized neuronal networks, aphasic persons—whose speech may become grievously impaired or consist only of short guttural attempts at words—often use expletives as an alternative means of communication. A clergyman cared for after a stroke spoke principally in expletives, becoming agitated and depressed by his inability to suppress them. Damage to his left hemisphere, which contains speech centers, interfered with his ability to speak using expletives, indicating these words are stored and retrieved via different brain circuitry than normal speech.

The right hemisphere and underlying subcortical systems are important for formulaic language: words heard or spoken so often over the years that they become overlearned. This category includes names, prayer phrases, National Anthem lines, clichés, small talk, automatic phrases like “thank you,” and most importantly, expletives. The brain treats expletives differently among all formulaic words by establishing a strong link between the words and the circuits mediating emotions.

Cultural drivers of acceptance

Our national increase in the use of expletives roughly parallels the rise in televised streaming services compared to traditional movie-going. Different standards apply to these technologies. According to the Federal Communications Commission Consumer Guide, “The same rules for indecency and profanity do not apply to cable, satellite TV and satellite radio because they are subscription services.” This grants streaming services a pass, leading to extensive use of profanity in recent productions.

Expletives derive from the Latin word expletivus, meaning “serving to take up space,” and usually refer to overlearned, emotionally charged words. Traditionally considered forbidden except in informal conversations among intimates, their usage has shifted. Many people employ expletives even in serene mental states, not just when frustrated, impatient, or angry. Some overwork them as fillers, as seen in a coffee shop conversation where one speaker used the F-word repeatedly in a single narrative about a missed meeting.

Pain tolerance effects

Expletives can favorably alter bodily and emotional responses. In a classic experiment measuring how long a person could keep a hand submerged in ice water, 73 percent of participants who swore during submersion increased their time in the frigid water by about 30 seconds. Another experiment found that repeating the word "f*ck" increased the pain threshold to ice water by 32 percent and pain tolerance by 33 percent compared to participants who repeated non-expletive words beginning with the letter F.

Unfortunately, these favorable effects on pain tolerance eventually disappear. Increased activity in the amygdala and prefrontal cortex also diminishes if the expletive is repeated endlessly in a perfunctory manner. Habitual users eventually penalize only themselves, enduring more pain in the future whether they swear or not. This phenomenon is documented in research by Hay Carlie M, Sills JL, Shoemake JM, Ballmann CG, Stephens R and Washmuth NB (2024), titled “F@#$ pain! A mini-review of the hypoalgesic effects of swearing,” published in Front. Psychol. 15:1416041.