Learn in the textbookRisks and Social Issues of AI
DefinitionHallucination (ハルシネーション) is when generative AI outputs content that is not true in natural-sounding text, as if it were correct.
ExplanationGenerative AI builds sentences by picking likely next words from patterns in the text it learned, so the word-picking itself never checks whether the content is true. It may give nonexistent references or wrong figures in a confident tone. When the output is used for work, the user confirms the facts with another source.
AnalogyIt is like someone who half-remembers a route but gives directions without a trace of doubt. The surer they sound, the harder it is to question them.
Memory hookA hallucination is seeing something that is not there; here, the AI states facts that are not there.