Dash it all! Why the em dash can’t be trusted

Longer than a hyphen, bolder than an en dash, and beloved—perhaps too beloved—¹ by stylists, the em dash has always lived a double life: both elegant and unruly, formal and anarchic. It may be the typographical equivalent of a knowing smirk. But how did this versatile punctuation mark become such a source of controversy, particularly in the age of ChatGPT?

A short history of a long dash

The em dash (—)², so-called because it’s roughly the width of a capital “M,” is the typographic offspring of the printing press. While early manuscripts and printing relied on simple punctuation like periods and commas, the dash as a concept took off in the 18th and 19th centuries, thanks in large part to writers like Laurence Sterne and Emily Dickinson, who used it to mimic thought, hesitation, or abrupt shifts in tone. It gave writers a new tool: the pause-without-a-full-stop.

The en dash (–), meanwhile, is half the length, originally used for ranges (1914–1918) or to connect related concepts (the London–Paris route). The humble hyphen (-), smallest of all, is used to glue compound words together (half-truth).

What’s the em dash for, exactly?

Herein lies the beauty and the problem. The em dash defies easy categorisation. It can:

1. Replace commas for parenthetical asides

   My brother—the one who lives in Norway—sent me a fish.

2. Replace colons for dramatic effect

   She had one ambition—power.

3. Mark interruptions in dialogue

   “But I thought you said—” “I didn’t.”

4. Convey an unfinished or trailing thought

   If only he had—well, never mind.³

It’s a chameleon, which makes it ripe for overuse. In the hands of a careful writer, it adds rhythm and nuance. In the hands of an AI, or an overexcited copy editor, it becomes a crutch. A stylish one perhaps, but a crutch nonetheless.

The ChatGPT em dash controversy

Which brings us, rather inevitably, to ChatGPT. As the language model has risen to prominence, a strange typographical pattern is emerging. Users noticed the frequent appearance of the em dash - sometimes several in a single paragraph - where once a comma or colon might have sufficed.

OpenAI have acknowledged the “em dash issue” and claimed it is a result of stylistic convergence. The model had absorbed mountains of digital text, academic articles, journalistic prose, blogs, many of which favoured the em dash as a modern marker of style. In trying to sound human, ChatGPT simply did what many humans do: it dashed too often.

It has now become a hallmark of AI-generated prose. Scan a paragraph and spot the em dash: chances are, a language model had a hand in it. Where human writers might reach for a colon, a semicolon, or the humble comma, the em dash offers a ready-made shortcut: versatile, visually striking, and, crucially, low-risk.

Now, human writers—perhaps stung by the association—have begun to protest too much.⁴ “I’ve always used em dashes,” they insist, with the weary indignation of someone wrongly accused of plagiarism. Twitter threads and Substack notes erupt in earnest self-defence: I use them for voice. For pace. For nuance. As though their fondness for a long horizontal line predates the machine’s mimicry, and therefore absolves them of suspicion.

How the hell do you type an em dash?

But here’s the thing: typing an em dash is not easy. I love using en dashes, and, if you’re sufficiently interested, there's a long tradition of them in my published work, all pre-dating GenAI. But even using en dash is tricky. When I’m typing into an MS Word document, a hyphen is automatically turned into an en dash if you leave a space before and after it:

An en dash – well placed – acts as a raised voice, drawing attention to what’s within its parenthesis. Brackets (on the other hand) signify a lowered voice, a hushed tone, a moment of semi-private reflection. An embedded subordinate clause, one like this, that merely uses commas is the neutral state, the diffident shrug of parenthetic punctuation.

Me, blocked quoted just because.

But, although I’ve of course encountered them in other people’s writing, I have never used an em dash. Why? Because I have (or had) no idea how to. In order to find out, and not unaware of the irony, I asked ChaptGPT. Here’s how you do it:

On a Mac:

Press Option + Shift + - (hyphen key)

This gives you a clean em dash — no spaces needed.

On Windows:

Hold Alt and type 0151 on the numeric keypad (not the number row).

So: Alt + 0151 = —

Note: This only works if you have a numeric keypad.

In Word or Google Docs (auto-replace):

Typing two hyphens between words (like this – and then hitting space) often autocorrects to an em dash.

This can be hit and miss, depending on your settings.

On phones or tablets:

Press and hold the hyphen - key. You’ll get a pop-up offering the em dash (—) and en dash (–). Slide to choose.

Now, it may be that most — maybe even all — of the em dashes⁵ are produced by hard working human fingers, but I don’t buy it. Not having known about this keyboard hack, most of my ‘dashes’ on Substack are just hyphens (a few of my posts are typed on Word and then copied across and thus contain en dashes) but if you ever spot an em dash in my work it’ll be because I got Chat GPT to tidy something up.

Probably best avoided

The em dash is not the villain. If you’ve been going through all the faff of holding down Alt and typing 0151 all this time then I feel for you. Being tarred as a robot must feel grossly unfair. But everyone else: we see you. We know you’re bullshitting. At least go to the effort of editing your AI generated prose with alternative punctuation marks. If you can’t do that, I’m not convinced there’s much human hand in the slop you’re producing.

To avoid accusations of AI plagiarism - justified or not - follow a simple rule: if in doubt, take it out.

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Think I’m wrong? Are you a pure and justified em dash user cruelly pigeonholed as a plagiarist by my lazy streotypes and blythe assumptions? Let me know.

1. I got ChatGPT to deliberately put those two in.

2. And that one.

3. Yep, it did all these ones too.

4. I copied and pasted these ones (and emboldened them for effect)

5. I just used Option + Shift + - to types those two. So exciting!