Em-dashes have become a telltale sign of AI-generated text, which has created some funny side effects.
I now frequently see correct and incorrect usage of hyphens and dashes mixed in the same piece of text. This happens when someone revises a piece of AI-generated text but doesn't understand the difference between hyphens, en-dashes, and em-dashes.
It's also pretty obvious that some people have started find-replacing all em-dashes with single hyphens (-) or double hyphens (--) to hide that they used AI. Which, of course, is its own tell.
But this still doesn't hide the most obvious giveaway, which isn't the em-dash itself. LLMs almost always put spaces around em-dashes: word — word instead of word—word. My guess is that models are heavily trained on news data, where the AP style guide, most commonly used in journalism, recommends spaces around em-dashes. Books and most professional writing use them without spaces.
So if you're taking your writing seriously, there's no way around learning how to use hyphens, en-dashes, and em-dashes correctly. I wrote a short post explaining the differences on my blog: Hyphens and Dashes
Hyphens and Dashes
With AI tools becoming widely adopted, em-dashes have become a telltale sign of AI-generated content. Claude and ChatGPT seem to love them, which is unfortunate, because it’s now made everyone suspicious of a perfectly good punctuation mark. But this doesn’t change the fact that most people (non-native and native English speakers alike) never learned or understood the difference between hyphens (-), en-dashes (–), and em-dashes (—) in the first place. I now frequently see correct usage (AI-generated) and incorrect usage mixed in the same document, which happens when people do not understand the difference and revise a piece of AI-generated text.
[... 659 words]I think for anybody in any field, if they write about the edge of what's happening in their field, [...] it really hones your thinking, because when you write something down and you do it all the time, there's this inner desire to not be intellectually inconsistent and so you hold yourself actually to understanding things. Going back to that word nuance, you really get into the nuance because you really want it to hold together once you put something down on paper and there are plenty of people outside of ourselves that have studied this writ large, but it's very well understood that writing is a great way to understand things to take it to a higher level.
— Bill Gurley, Stratechery interview about Gurley's book Runnin' Down a Dream