The AI Tells Nobody Agrees On (and the Ones the Data Actually Supports)
There's a lot of confident folk wisdom floating around about how to spot AI-written text: count the em dashes, look for "delve," check if every sentence has three items in it. Some of that folk wisdom holds up under scrutiny. Some of it doesn't. I went looking for the actual research behind the most common claims, built a tool to test them against real text, and the tool immediately proved one of my own assumptions wrong. Here's what I found, what I built, and what I'd get wrong if I trusted intuition alone. The short version AI writing tells fall into four categories with very different levels of evidence behind them: Lexical overuse — specific words with measured, statistically significant frequency spikes since ChatGPT's launch. This is the best-documented category. Structural and rhetorical patterns — predictable sentence architectures ("it was not X, it was Y," three-item lists) that show up repeatedly in AI-generated prose but hav...