{"slug": "llms-could-write-like-humans-but-post-training-guardrails-make-their-text", "title": "LLMs could write like humans but post-training guardrails make their text detectable", "summary": "Bradley Emi, CTO of AI text detector Pangram, argues that large language models like ChatGPT, Claude, and Gemini could write as diversely as humans but post-training guardrails cause 'mode collapse,' making their text detectable. Pangram's detection does not flag base models, narrowly specialized fine-tunes, or broken outputs, but watermarks will likely always work even with base model variety.", "body_md": "# LLMs could write like humans but post-training guardrails make their text detectable\n\n**LLMs could theoretically write as diversely as humans, but they don't.** Post-training and safety guardrails keep their text detectable, argues Bradley Emi, CTO of AI text detector Pangram, in a [blog post](https://pangram.substack.com/p/no-llms-dont-just-mimic-human-text). Systems like ChatGPT, Claude, or Gemini learn behavioral rules to avoid dangerous outputs or censor certain political statements. This sharply narrows their expressive range, an effect called \"mode collapse.\"\n\nSo-called base models, the raw models before post-training, write with more variety, so Pangram's detection doesn't flag them, Emi says. The [same goes](https://x.com/max_spero_/status/2089938824474263644) for narrowly specialized fine-tunes trained only on Hemingway or certain subreddit texts, and for broken outputs like incoherent text. This only applies to non-watermarked AI text, though. [Watermarks will likely always work](https://the-decoder.com/anthropic-watermarks-claudes-output-but-critics-question-the-tradeoffs/), even with a base model's variety.\n\n```\nAI News Without the Hype – Curated by Humans\n\n\t\t\t\t\tSubscribe to THE DECODER for ad-free reading, a weekly AI newsletter, our exclusive \"AI Radar\" frontier report six times a year, full archive access, and access to our comment section.\t\t\t\t\n\n\t\t\t\t\tSubscribe now\n```\n\n[Pangram](https://pangram.substack.com/p/no-llms-dont-just-mimic-human-text)", "url": "https://wpnews.pro/news/llms-could-write-like-humans-but-post-training-guardrails-make-their-text", "canonical_source": "https://the-decoder.com/llms-could-write-like-humans-but-post-training-guardrails-make-their-text-detectable/", "published_at": "2026-08-20 17:36:51+00:00", "updated_at": "2026-08-20 17:44:48.088803+00:00", "lang": "en", "topics": ["artificial-intelligence", "large-language-models", "ai-safety", "ai-tools"], "entities": ["Bradley Emi", "Pangram", "ChatGPT", "Claude", "Gemini"], "alternates": {"html": "https://wpnews.pro/news/llms-could-write-like-humans-but-post-training-guardrails-make-their-text", "markdown": "https://wpnews.pro/news/llms-could-write-like-humans-but-post-training-guardrails-make-their-text.md", "text": "https://wpnews.pro/news/llms-could-write-like-humans-but-post-training-guardrails-make-their-text.txt", "jsonld": "https://wpnews.pro/news/llms-could-write-like-humans-but-post-training-guardrails-make-their-text.jsonld"}}