The test before the lesson

A teacher gives a short test on material the class has not been taught. Students get most of it wrong, which is expected, and then the lesson begins. On a later assessment, this group outperforms a class that simply had the lesson.

The finding is sometimes called the pretesting effect and it is genuinely strange, because the students were guessing and the guesses were mostly incorrect. Being wrong apparently prepared them in a way that being told did not.

The explanation researchers favour concerns attention. A question you have already attempted and failed creates a specific gap. When the answer arrives in the lesson, it lands somewhere: it is not information in general but the answer to something you wanted ten minutes ago. Students who were simply told the same thing had no gap for it to fill, so it arrived as one more fact among many.

There is a condition attached that teachers sometimes miss. The effect depends on the answer arriving soon afterwards. A failed test with no follow-up teaches nothing except that the subject is hard, and may do harm.

The practical version for a student revising alone is to attempt the questions at the end of a chapter before reading it. It feels like a waste of eight minutes and it produces a strange experience: reading the chapter afterwards is noticeably sharper, because you are now looking for something rather than absorbing everything equally.