Definition
Plain language
When an AI assistant ends up sounding the same way no matter what you ask it.
As stated in the literature
A post-RLHF failure mode in which the model's output distribution becomes narrowly peaked, reducing diversity across prompts.
Why it matters: Collapsed outputs hurt creativity, calibration, and exploration, and they can mask underlying capabilities the model still has.
For example, a chatbot keeps opening every reply with the same upbeat phrasing regardless of whether you asked about taxes or pasta.
Heard on the show
“Separately, people have talked about mode collapse — the post-RLHF model gets stuck producing the same kinds of outputs.”Episode 070 — When Models Know the Answer But Say the Wrong Thing Anyway