Why do AI models make things up?

Question

Accepted Answer

AI models hallucinate because they generate the most plausible-sounding next words, not verified facts. When they don't know something, they don't stay silent. They produce a confident guess that fits the pattern of a real answer, which is why a made-up citation or statistic can look entirely legitimate.

The model has no built-in sense of truth and no memory of where its knowledge came from. It's optimizing for fluent, likely text. Most of the time that overlaps with correct, but the two aren't the same thing, and the model can't tell you which is which.

You reduce hallucination by giving the model the source material to work from (retrieval), asking it to cite what it used, and keeping a human check on anything that matters. You don't eliminate it. Treat AI output as a strong draft, not a final authority.

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