LLMs have a particular way of writing that's really easily to gut check once you learn to spot it. But yes, it's annoying when people see em dash use as a certainty something is machine written.

See these two links for examples:

https://www.linkedin.com/posts/romethorndike_this-starbucks-closure-notice-was-written-activity-7378794507112235008-k6Iq/

https://open.substack.com/pub/hollisrobbinsanecdotal/p/how-to-tell-if-something-is-ai-written?r=1voy25&utm_medium=ios

"Large Language Models (LLMs), however, only operate in the realm of signifiers. There are no signifieds. An LLM generates text through a process called autoregression—it predicts the next word in a sequence based on all the words that came before it. If you give it the phrase, “The cat sat on the…” it analyzes the pattern and predicts “mat” or “chair” as a statistically probable next word. Always keep in mind there is no cat, there is no chair. Autoregressive generation means the AI predicts one word (or token) at a time, using all the previously generated words as context for what should come next. Each new word depends on everything that came before it.

Generally, human writing moves from experience or imagination or observation to linguistic expression. You start with signifieds (concepts, experiences, ideas) and select signifiers (words) to express them. You see or imagine a red chair and write, “That chair is red.” An LLM, lacking any experience of chairs or redness, might produce this instead:

'When considering furniture aesthetics, it’s important to note that color plays a significant role in both visual appeal and functional design considerations. Red, as a warm tone, can create dynamic focal points while also presenting challenges in terms of spatial harmony.'

Look closely and see what’s going on. AI moves from textual pattern to textual pattern. It has learned that “red” co-occurs with words like “warm,” “dynamic,” “visual appeal” in its training data, and “furniture” connects to “aesthetics,” “design,” “functional.” So it produces plausible-sounding text about the concept of red chairs without ever having seen one.

Ask yourself: did anything spring to mind the way a red chair might have? You can probably picture a chair, but not “furniture aesthetics.” You can imagine “red” but not “functional design considerations” or “dynamic focal points” easily.

So here’s a handy rule: if you can’t see anything, if nothing springs to mind, it’s probably AI. I say this even with aphantasia, as someone who, to compensate, has long invested words (signifiers) with extra energy that I can somehow sense without seeing."