Passive learning
Passive learning is taking information in without doing much with it, like rereading your notes or watching a lecture without pausing. It feels productive, but it builds a sense of "I've seen this" instead of real memory, so it sticks poorly when you need it later.
When you reread or highlight, your brain stays in recognition mode. The words look familiar, so you feel like you know them. That familiarity is a trap. Recognizing something on the page is not the same as being able to recall it in an exam, with the page closed.
Active learning is the opposite. Instead of re-reading, you quiz yourself, explain an idea out loud, or do practice questions. You make your brain pull the answer from memory. That pulling is what builds strong, lasting recall. Studies keep showing students who test themselves remember far more than students who only reread.
The fix is not to drop passive study completely. Reading first is fine to get the basics in. The mistake is stopping there. Read once, then switch to recalling, testing, and explaining.
Mara reads her biology notes three times the night before her test and feels ready. The next day she stares at a question on the cell cycle and goes blank. She knew the words when she could see them, but she never practiced bringing them back from memory.