The em dash is not an AI problem. Every list of AI writing ‘tells’ you to watch out for the dreaded em dash. If you see an em dash then it’s definitely AI. No doubt about it. 100% fine-milled AI slop.

And people believe this without question.

Some people take it further, claiming that because they glanced down at their keyboard for 2 seconds and couldn’t see an em dash key, no human would ever go through the gruelling process of inserting a character that needs more than a single keystroke. The obvious conclusion being that the em dash is a purely machine-brained creation that never existed before about 3 or 4 years ago.
(It’s frankly bleak how many times I’ve seen that one pop up.)
The advice that follows the list of “AI Detection for Dummies” is usually: remove all em dashes. If you see one, cut it. Train yourself out of the habit. Dashes begone. Bash the dash. Cede the territory to our robot overlords.

You can take the em dash from my cold, dead hands*.

As a copywriter I quite like having the full palette of punctuation available to paint with. Alt+0150 for an en dash (–) and Alt+0151 for an em dash (—) are both instinctive muscle memory at this point, developed after years in the copy mines.

I repeat: the em dash is not an AI problem. It is — if anything — an overuse problem, and overuse is a different thing. AI language models were trained on (among many other things) vast swaths of fanfiction, and that tends to be something of a sea of dashes thanks to young, inexperienced writers trying to find their voice. The AI overuses them because some actual, real human writers were overusing them and had been for decades.

So, explain to me again how is it’s a machine’s tell all of a sudden?

_{*Please don’t do that.}

OK, so what is it supposed to be for?

Wielded with care, the em dash more than earns its place in my writing as it should in yours.

The em dash does something specific that other punctuation does not.*

A comma connects. A semicolon balances. A colon introduces. The em dash — used well — interrupts. It creates a gap in the flow of a sentence that makes the reader feel, briefly, the shape of the thought. It can introduce an aside that reframes what came before. It can land an unexpected close. It can hold two things in tension in a way that a comma cannot quite manage and a full stop would destroy.

These are real effects. They are not effects that can be achieved by other means without cost. Replacing every em dash with a comma produces ‘smoother’ prose. It also produces prose that never catches the reader mid-stride and says: wait, here’s the thing you did not see coming**.

That is a real loss. I am not prepared to accept it because AI has developed a fondness for dashes it does not fully understand***.

_{* Henry Fowler, in Modern English Usage (1926), described the em dash as “the least careful writer’s most useful device.” He did not mean this as a compliment. He was right, though, that it is useful, and right that careless writers reach for it when they have not decided what the relationship between two clauses actually is. The answer is not to ban the dash. It is to decide the relationship first, and then choose the punctuation that reflects it.}

_{** M. Dash Shyamalan}

_{***There’s also an argument to be made that the writers of many a US-centric style guide also do not fully understand the em dash. A number of the most commonly used US guides will insist that the em dash be used with no spaces, rendering it an overfed hyphen to the reader’s eye and making it more difficult to parse the intended meaning on first pass. I consider these guides’ authors to be history’s greatest monsters.}

A dash of seasoning

The AI em dash is recognisable once you know what to look for.*

It appears before conclusions. It appears after setup phrases, creating a pause that implies profundity without delivering it. It is used for rhythm in places where the rhythm has not been earned. It is the punctuation equivalent of the meaningful look — the pause that says something important is happening here while nothing important is happening.

This is not the same thing as the em dash I am defending.

The em dash I am defending is the one that does something a period would not, a comma could not, and a colon would get wrong. It is the one that appears after deliberation rather than by default. The situations that call for it can be rare, and using it more often than those situations demand is how you end up fielding accusations of writing like a language model.

_{*The specific thing AI does with em dashes that is easiest to detect: it uses them to create a pause before a conclusion, as if the pause itself confers profundity. This is something it learned from the aforementioned fanfiction writers. “The answer was obvious — it always had been.” The dash is doing nothing here. The conclusion would land the same — or better — without it. In more skilled human writing, the em dash earns its place by creating a specific effect: interruption, apposition, the aside that reframes what came before. When it is used purely for rhythm, it is not an em dash. It’s a comma with ideas above its station.}

Dash it all

There is a broader argument here that goes beyond punctuation.

A significant amount of current advice about writing in the age of AI is advice about how to make your writing look less like AI writing. Avoid certain words. Avoid certain structures. Avoid certain punctuation marks. The underlying logic is: AI has colonised these territories, so retreat from them. Write around the model. Signal your humanity through absence.

This is the wrong frame.

The question is not which tools AI has picked up and therefore tainted. The question is which tools produce the effects you are trying to produce, in the specific sentence you are writing, for the specific reader you are writing for. If the answer to that question is an em dash, use an em dash. If AI also uses em dashes, that is AI’s problem, not yours. You might just be in agreement because it was a fitting place for the dash. Your job is not to write differently from AI. Your job is to write well and then trust the reader to tell the difference.

(And as a side note, AI detectors are generally as reliable as using a Y-shaped stick to find sources of water. You get as much of an accurate answer if you asked it for signs the piece was written by a Capricorn).

If you really want a TL;DR version: surrendering the em dash to AI is not how you write more like a human.

Intentionally writing like a human talking to other humans is how you write like a human.