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Working with language modelsLast reviewed
Hallucination
Hallucination is when a language model makes up statements that sound convincing but are false or unsupported.
Also known as: Confabulation
How it works
A language model predicts chunks of text, it does not check facts. If it lacks knowledge or the question is unclear, it fills the gap with whatever sounds plausible. This is how invented numbers, false source references or claims that sound like facts come about.
A practical example
You ask for a study on a topic and get authors, title and year — but that study does not exist.
What you should know
- Hallucinations can be reduced but not ruled out completely.
- Helpful measures: base answers on your own sources (RAG), have sources shown, write precise prompts and have a human check important content.
- Especially with numbers, quotes, and legal and medical topics: verify before you pass anything on.