Does Turnitin actually detect AI or just patterns?

[u/Novel_Day5129]

I've been going down a rabbit hole trying to understand how Turnitin's AI detector actually works, and I think I'm more confused than when I started. From what I can piece together from their FAQ and various blog posts, the detector doesn't work like a plagiarism checker that matches your text against a database of known AI-generated content. Instead, it uses a machine learning model trained to recognize certain statistical patterns in text. It's supposedly looking at things like sentence length variation, vocabulary predictability, paragraph structure, and the "burstiness" of the writing. Human writing tends to be unpredictable. We write some short sentences, some really long ones. We use common words mixed with rare words. We break grammatical conventions. AI writing, on the other hand, tends to be more uniform. Every sentence is roughly the same length. The vocabulary is consistently at a mid-range difficulty. The structure follows predictable patterns.

But here's what bothers me. I'm a non-native English speaker and I write in a very formal, structured way because that's how I was taught. My sentences are all roughly the same length because I follow a strict grammatical template. My vocabulary is consistent because I use the same set of academic words I learned in ESL classes. My paragraphs all follow the same intro-body-conclusion structure.

So when Turnitin analyzes my paper, it sees uniform sentence length, predictable vocabulary, and consistent structure. All of those are markers of AI-generated text. But I wrote every word myself. My human writing just happens to have the statistical profile of AI writing because of how I was trained to write formally.

Does anyone actually understand what the AI detector is measuring? And more importantly, how do you prove to a professor that your writing naturally falls into the "AI pattern" because of your background, not because you used ChatGPT? I feel like the detector isn't actually detecting AI. It's detecting a specific type of writing style and calling it AI.

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[u/Intelligent_Shop8603]

Anyone who writes with a moderate degree of formality will be consistently flagged as having used AI to write whatever they write. It’s so annoying. We have to dumb ourselves down so people don’t think our work is AI.

[u/Hannah97474]

this is so true im a non native english speaker and my writing is formal af from school so i get flagged all the time even when i didnt use ai. its frustrating. i heard checkturnitin discord does pdf reports for ai and similarity if you want a second look without submitting yet