Ask an AI about a book that does not exist and it will tell you the plot, the author's background, the year it was published and the prize it won. None of it is real. This is called <b>hallucination</b>, and it is the single most important thing a student needs to understand before using AI for homework.
Lying requires knowing the truth and saying something else. The model does neither. It continues text, and your question was a shape that needed filling.
Asked about a novel called The Silver Compass by Anita Rao — which does not exist — a model will happily produce a coastal setting, a cartographer's daughter, and a Crossword Book Award. Every detail is generated because it is the sort of detail that fits.
Invented answers and correct answers are written in the same handwriting. Same confidence, same fluency, same full stop.
The model never signals uncertainty, because it has no mechanism to. It cannot tell you it was a coin toss.
Hallucinations are most convincing exactly where you know least — which is exactly where you were relying on it.
Give it the source. Most hallucination happens when the model has nothing real to read. Paste the actual page, chapter or data and it will read it.
Tell it what to do when it doesn't know. "If it is not in the text, write NOT GIVEN. Do not estimate." This one line removes a surprising amount of it.
Check anything you would be embarrassed to be wrong about. Especially names, dates, numbers and citations — the four things it invents most and you check least.
Five confident facts about a book that has never been written. Nothing on the screen suggested anything was wrong.
In our free course you ask about a book that does not exist, read the confident answer, then strike out every invented claim yourself.
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