# Models Produce Hallucinations Because of Probabilistic Training

> Source: <https://letsdatascience.com/news/models-produce-hallucinations-because-of-probabilistic-train-3bcd67a0>
> Published: 2026-07-03 17:48:13+00:00

Large language models produce **hallucinations**, confident but factually wrong statements, because they are trained as probabilistic next-word predictors on data that mixes reliable sources with fiction and repeated misinformation, according to a July 3, 2026 explainer from Portuguese tech outlet TugaTech. OpenAI's own research (Kalai, Nachum, Vempala and Zhang, **September 2025**) adds a sharper mechanism: hallucinations persist largely because standard accuracy-based evaluations reward confident guessing over honest uncertainty, so models learn to guess rather than say `I don't know`. For practitioners, the takeaway is operational: hallucinations are a structural property of current training and grading, not a bug to patch, requiring explicit verification, calibration, and fallback design rather than hoping bigger models will resolve it on their own.