One of the most common claims circulating online is that the use of the em dash (—) is a telltale sign of AI-generated writing.

Not quite.

The em dash wasn’t invented by AI. It has been part of English typography for centuries and has long been used by professional writers, editors, journalists, and publishers to add emphasis, introduce interruptions, or create a more natural rhythm in a sentence.

What has changed is that AI systems tend to use em dashes correctly and quite frequently. As a result, many readers have started associating them with AI-generated text—even though there’s nothing inherently artificial about using them.

In fact, English uses three different horizontal punctuation marks, each with a distinct purpose:

• Hyphen (-): joins words (well-known, AI-generated).
• En dash (–): indicates ranges or connections (pages 12–18, London–Paris flight).
• Em dash (—): creates a pause, adds emphasis, or sets off a thought—like this.

Perhaps the real reason many people avoid en dashes and em dashes is much simpler: unlike the hyphen, they don’t appear on most keyboards and usually require keyboard shortcuts or special character insertion.

Knowing the difference won’t make your writing sound more like AI. It will simply make it more precise.