Not denying this is true — but like a lot of what we've seen with AI, lets see how you feel in two years time when the models have improved as much.
I think it was actually Brian Eno that said it (essentially): whatever you laugh about with regard to LLMs today, watch out, because next year that funny thing they did will no longer be present.
Comparing base and instruction-tuned models, the base models are vaguely human in style, while instruction-tuned models systematically prefer certain types of grammar and style features. (For example, GPT-4o loves participial clauses and nominalizations.) https://arxiv.org/abs/2410.16107
When I've looked at more recent models like o3, there are other style shifts. The newer OpenAI models increasingly use bold, bulleted lists, and headings -- much more than, say, GPT-3.5 did.
So you get what you optimize for. OpenAI wants short, punchy, bulleted answers that sound authoritative, and that's what they get. But that's not how humans write, and so it'll remain easy to spot AI writing.
Despite all the complaints about AI slop, there is something ironic about the fact that simply being exposed to it might be a net positive influence for most of society. Discord often begins from the simplest of communication errors after all...
Our experience (https://arxiv.org/abs/2410.16107) is that LLMs like GPT-4o have a particular writing style, including both vocabulary and distinct grammatical features, regardless of the type of text they're prompted with. The style is informationally dense, features longer words, and favors certain grammatical structures (like participles; GPT-4o loooooves participles).
With Llama we're able to compare base and instruction-tuned models, and it's the instruction-tuned models that show the biggest differences. Evidently the AI companies are (deliberately or not) introducing particular writing styles with their instruction-tuning process. I'd like to get access to more base models to compare and figure out why.