The science

The science of swearing

A fuller account of what neuroscience, psychology and corpus linguistics have found, for readers who want more than the short version. Where a finding is contested or small, it says so.

Where swearing lives in the brain

The evidence that swearing is handled differently from ordinary speech comes mostly from what happens when the brain breaks.

• Aphasia. Since the neurologist John Hughlings Jackson described it in the 1870s, clinicians have noted that patients who have lost propositional speech after left-hemisphere damage often keep "automatic" speech: counting, song lyrics, prayers and swearing. A patient who cannot name a cup may still say "oh fuck" fluently when they drop it. The inference is that swear words are stored as whole emotional units in right-hemisphere and subcortical systems, rather than assembled in the left-hemisphere language areas.
• Tourette's syndrome. About one in ten people with Tourette's experiences coprolalia, involuntary swearing. The words produced are the taboo words of the patient's culture, in the patient's language, and occur alongside other tics that are driven by the basal ganglia. Coprolalia is the strongest evidence that the brain treats taboo words as a distinct category, and that the category is learned, since Japanese patients produce different words from British ones.
• Imaging. Functional MRI and EEG studies show taboo words producing a larger skin-conductance response and more amygdala activity than neutral or even negative non-taboo words, and being remembered better in recall tests. The word does not simply mean something rude; it is emotionally arousing in a way "poo" is not.

Pain

Richard Stephens's group at Keele University has published a series of studies since 2009. The first found that repeating a swear word roughly doubled the time volunteers could keep a hand in ice water, with a higher heart rate, suggesting a fight-or-flight mechanism. A 2011 follow-up found the effect much weaker in people who swore frequently in daily life, consistent with habituation. A 2018 study found that swearing also increased strength and power in short bursts of exercise. A 2020 study using invented words ("fouch", "twizpipe") found no effect at all, ruling out distraction or humour and pointing back to the taboo. The findings have replicated in several labs, though effect sizes are moderate and the mechanism is still argued over.

Emotion and aggression

Swearing reduces self-reported anger and, in some experiments, reduces subsequent aggression, in line with a catharsis account. The cautions are that the studies are small, that a competing account says swearing rehearses aggression, and that both may be true depending on whether the swearing is directed at a person. The most consistent finding is a simple one: people say they feel better after swearing at a frustration, and their physiology agrees.

Who swears, how much

Timothy Jay, whose work at Massachusetts College of Liberal Arts underpins most of this field, estimates that swear words make up roughly half a per cent of everyday speech, comparable to first-person plural pronouns, and that the average speaker uses around eighty to ninety a day. Ten words account for the great majority, and fuck and shit between them for around a third to a half of all swearing in American English. Corpus studies of British speech (McEnery and Xiao 2004 on the original British National Corpus; Robbie Love 2021 comparing it with the 2014 spoken corpus) find that:

• Fuck and its forms are the most frequent strong swear words in British conversation, and their use roughly doubled between the early 1990s and mid-2010s while "bloody" fell away.
• Men swear more than women overall, but the gap has narrowed sharply, and for fuck specifically women's use increased most.
• Swearing peaks in the late teens and twenties and declines with age.
• Working-class speakers swear more than middle-class speakers in recorded conversation, though the class effect is smaller than the age effect and complicated by who is being recorded with whom.

See Statistics for the figures in tables.

Swearing in a second language

Jean-Marc Dewaele's research at Birkbeck, and Catherine Harris's skin-conductance work, both find that swear words in a language learned after childhood produce a weaker emotional response than those in a first language. Bilinguals report that swearing in their second language feels "like a game" and that they prefer their first language for anger. This is why the English word is milder for a German than ficken, and why it is so widely borrowed: for most of the world, fuck is a swear word without the sting.

Swearing and personality

A cluster of studies from Kristin Jay and Timothy Jay (2015) found that fluency in swear words correlates with general verbal fluency, against the folk belief that swearing marks a poor vocabulary. Feldman and colleagues (2017) reported a link between profanity and honesty at individual and state level, which has been contested on methodological grounds. Studies of perception find people who swear are seen as more intense but not less competent in informal contexts, and less competent in formal ones, which matches everyday experience.

Children

Jay's records of children's speech show swear words appearing by age two, a working vocabulary of taboo words by five or six, and adult patterns by early adolescence. Children learn from parents first and peers second, and learn the taboo along with the word. The best available evidence finds no harm to children from hearing ordinary swearing, as distinct from verbal abuse. See Children.