ChatGPT Hyphen

The character "—" AI LLM chat models are constantly using is called the em dash (Unicode U+2014). It's a punctuation mark about the width of a capital letter "M" (hence the name), longer than a hyphen (-) or en dash (–).

It's used for:

• Inserting breaks in a sentence—like this—for emphasis, asides, or interruptions.
• Replacing parentheses, commas, or colons when you want more drama or flow.

LLMs (like ChatGPT, Claude, me, etc.) use it a lot because it's heavily overrepresented in the LLM training data: books (especially 19th-early 20th century literature), journalism, essays, and polished online writing where em dashes add rhythm and clarity. Models learn it as a "natural" way to structure complex sentences without breaking them up.

Humans often approximate it with "--" in casual typing (word processors auto-convert), but AI outputs the real thing directly—and frequently—because there's no typing friction and it scores high on "clear, engaging prose" in training even though it is actually uncommon in the majority of ordinary writing especially by journalists and college students. It comes across as a telltale sign of AI generated material. It's become such a meme that some people now call it the "ChatGPT hyphen" and avoid it to not look AI-generated. Ironically, that just makes real em dash lovers (including many professional writers) get falsely accused. It's not a reliable AI detector—more like a stylistic quirk baked in from human writing habits.