The Em Dash

Last summer, Bryan Vance found himself in an argument with a stranger on Reddit. Vance, a Portland-based journalist who runs Stumptown Savings, a newsletter covering local grocery deals, had been accused of using ChatGPT to write his content. The evidence? His use of em dashes.

“A Reddit user accused me of using AI, pointing to my use of, quote, extra long M dashes that are not possible to replicate on a normal keyboard,” Vance recalls. The accusation stung, particularly because Vance spends 40 hours a week personally visiting grocery stores and crafting his newsletter by hand. “I’m a human, I can confirm I’m human,” he says.

This plucky bit of punctuation has had a very, very long literary history way beyond today’s tussles with technology. It’s been on a hero’s journey, playing the lead in an adventure story that has spanned both centuries and the pages of our most beloved plays, novels and poems. So who invented it—and why?

Humble Beginnings

The em dash gets its name from its width, roughly equivalent to a capital M. Its origins trace back to 11th century Italy and a scholar named Boncompagno da Signa, who practiced the formal art of composing letters and documents. Frustrated with the inconsistent punctuation rules of his time, he created his own system, including a horizontal dash called Virgula Plana that looked exactly like a modern em dash.

While his dash-as-period never caught on, the mark’s grammatical flexibility allowed it to evolve. According to Keith Houston, author of Shady Characters: The Secret Life Of Punctation, Symbols And Other Typographical Marks the dash slid into the printing era without a fixed purpose, which may have made it remarkably adaptable.

Shakespeare’s Stage Direction

By the 16th and 17th centuries, playwrights discovered the dash’s dramatic potential. They used it to indicate pauses, interruptions, and mid-speech realizations. Shakespeare’s First Folio is filled with them, giving actors flexibility in their performances and adding expressiveness beyond what periods and commas could provide.

The dash became essential for capturing a theatrical technique called aposiopesis, speech deliberately broken off mid-sentence. In King Lear, characters trail off with dashes as they lose their train of thought or shift direction, bringing psychological realism to the stage.

A Novel Tool

When the novel emerged as a literary form in the 18th century, writers adopted the dash to capture authentic human thought and speech. Lawrence Sterne’s 1759 satirical novel “Tristram Shandy” deployed dashes with wild abandon, creating a stream-of-consciousness narrative that felt revolutionary. One short excerpt contains seven dashes used in every conceivable way. “It must have been like a bolt from the blue,” Houston says. “It must have been so incredible for people at the time to read this.”

Novelists also used dashes for censorship, redacting names and locations to create an air of authenticity. Jane Austen employed this technique in her work, including in Pride and Prejudice using dashes to obscure military regiment names as if protecting real people’s reputations. The device added both realism and intrigue, helping sell these new works of fiction.

By the 19th century, dash usage exploded. Charles Dickens used one dash every 224 words in “Oliver Twist.” Herman Melville deployed them every 129 words in “Moby Dick.” Charlotte Brontë’s “Jane Eyre” features one every 90 words. But importantly, the em dash was a punctuation mark that could make a sentence feel more human. In real life we are naturally changing thoughts, cutting off others, or cutting off ourselves.

Emily Dickinson’s Signature

No writer became more associated with the em dash than Emily Dickinson. She composed nearly 1,800 poems in Amherst, Massachusetts, many during the Civil War, accompanied by thousands of dashes. Her dashes didn’t just indicate pauses; they captured the speed and ambiguity of human thought itself.

Dr. Fiona Green, who has studied Dickinson for decades, notes that the poet’s dashes create suspended moments of meaning. “She exploited unfinishedness,” Green explains. “The poems are always in the process, always undecided.” When Dickinson died in 1886, her editors stripped away most of her dashes before publication. Out of 1,151 dashes in her first collection, only 52 remained. Yet the poems became a sensation, never going out of print.

The em dash has always had critics. Jonathan Swift mocked excessive dashes in the 18th century. A reviewer complained about Lord Byron’s dashes appearing “sometimes twice or thrice in one line.” Modern style guides like The Chicago Manual of Style warn: “If in doubt, edit them out.” Even dash enthusiasts acknowledge the temptation to overuse it. “It’s easy to overuse the dash,” Houston admits. “I have to self edit to stop myself using it all the time.”

The ChatGPT Hyphen

Which brings us back to Bryan Vance and his Reddit troubles. Around 2024, people noticed that ChatGPT and other large language models had developed an em dash habit. The punctuation appeared so frequently in AI-generated text that younger internet users began calling it the “ChatGPT hyphen.”

When podcast host Theo Vonn asked OpenAI CEO Sam Altman about it, Altman claimed his team added more em dashes because users liked them. “Now I think we have too many,” he said. But Sean Goedecke, an industry insider, suspects something deeper happened.

When companies like Anthropic sought to expand their training data between 2022 and 2024, they turned to print books from earlier decades. Through “destructive scanning,” they bought millions of books, cut the pages from their bindings, and digitized them. “They kind of picked up the stylistic habits of these classic literature texts,” Goedecke explains, “which seem very incongruous when people use them today to write emails and job applications.”

The dash passed from Shakespeare’s hand into vast data centers, carrying centuries of literary tradition with it.

A Human Mark

It’s reductive to assume any writing with em dashes is AI-generated. After all, LLMs use the mark precisely because humans have deployed it for hundreds of years. There are subtler signs of AI writing: formal tone, specific vocabulary, a certain blandness. But the long, elegant dash is easy to spot and easy to target. It has become caught up in larger anxieties about artificial intelligence. For Dr. Green, the real concern isn’t spotting “real” versus “fake” writing. It’s what people surrender when they outsource thinking to machines. “Why would we introduce a machine? Why would we outsource exactly that perfect moment to something else?” she asks. “It’s the process of learning that then sends you out as a different human.”

In November 2025, Altman announced that ChatGPT would finally respect user requests to avoid em dashes. Perhaps some AI users will abandon them entirely. But for Bryan Vance and countless other human writers who appreciate its flexibility and flair, the em dash isn’t going anywhere. “It’s an odd thing to be a fan of an M dash,” Vance says, “but I am a fan of it. It’s a fun piece of punctuation.” After centuries of adventures across the pages of plays, novels, and poems, the em dash belongs with us.