Nobody taught me the em dash.

Maybe that's because I learned English in the deep south, and "them fancy dash thingys are just too highfalutin for us folk" or something. I sat through years of English class and I'm pretty sure it never came up. And it's definitely not on the keyboard.

There is no em dash key. You have to summon it (like some underworld demon) with an arcane key combo — chant in ASCII and the em dash appears — or just let autocorrect decide when you "deserve" one.

See what I mean? Once you give an AI an em dash, they start burying them in your prose like a rabid squirrel preparing for winter...

Yet somehow AI uses it constantly. Every other sentence. Like it went to a different English class than I did.

So I asked, and Claude replied...

AI was trained on an enormous corpus of published text — literary fiction, long-form journalism, academic writing, The Atlantic, The New Yorker, that entire universe of "serious prose." Em dashes appear constantly in that register. The model learned: em dashes = sophisticated writing. Human raters during training rewarded outputs that sounded literary. That behavior got reinforced. It compounded.

The AI learned to write from the ever so erudite New Yorker and never found the off switch for the pomposity. The human raters must have suffered from some sort of unidentified em dash invoking Tourette's.

Here's what I know: anything an em dash does, a period, a comma, or an ellipsis does better. Cleaner. With a key that actually exists.

If your AI drafts are full of em dashes, that's not style. That's punctuation apologizing for your prose. That's the model defaulting to punctuation nobody asked for, because The New Yorker used it, a rater approved it, and nothing ever told it to stop.

You're the off switch. Only you can prevent the spread of free-range em dashes.