Active Study: Why Self-Testing Works Better Than Rereading

The illusion of rereading

Rereading your textbook and highlighting passages feels productive: the material seems familiar, the reading flows, and everything makes sense. The problem is that recognizing isn’t the same as remembering. On a test, no one shows you the text to recognize; you have to retrieve the information from memory on your own.

That’s where active recall (also called retrieval practice) comes in: study by trying to remember without looking, then check your answer. The effort of retrieving the answer is exactly what strengthens your memory.

What the research shows

• The testing effect. In a widely cited experiment published in Roediger and Karpicke (2006), Psychological Science, students read short passages and then either reread the material or took tests where they wrote down everything they could remember. On a test taken minutes later, the students who reread did slightly better. But after two days and one week, the group that tested itself remembered more. Rereading wins in the short term and loses over the time frame that matters.
• Testing beats elaborate study techniques. In 2011, Karpicke and Blunt published a study in Science showing that retrieval practice led to better performance than creating concept maps, including on questions that required inference.
• Review of study techniques. A comprehensive review by Dunlosky and colleagues (2013), Psychological Science in the Public Interest rated self-testing and spaced practice as highly useful techniques, while rereading and highlighting ranked among the least useful.
• Interleaving. Studies by Doug Rohrer and colleagues using math exercises found that mixing problem types in the same session, rather than working through one type at a time, improves performance on later tests because it forces students to identify which method to use.

None of these findings mean that reading is useless: you need to engage with the material first. The question is what to do after that first read.

How to turn summaries into questions

Take an existing summary and rewrite each point as a question. Here’s an example from a biology passage:

Practical tips:

1. Use open-ended questions ("explain," "compare," "why") for concepts; use multiple-choice questions to practice the test format.
2. Answer without looking at your notes, then check your work. Getting things wrong is part of the process; corrected mistakes tend to stick.
3. Write down the questions you got wrong and try them again over the next few days.

For quick recall questions, Flashcards schedule your reviews automatically. For test-style questions with answer choices, an answer key, and explanations, paste your questions into the Quiz Generator and take the quiz right away—it also works for creating group practice tests.

An active study session plan

1. 5 minutes: Without looking at anything, write down everything you remember from the previous lesson (the so-called "blank page" exercise).
2. 25 minutes: Study new material, jotting down possible questions in the margins as you go.
3. 20 minutes: Solve problems that mix new material with topics you’ve already studied (interleaving).
4. 10 minutes: Check your answers, note any mistakes, and turn each one into a flashcard or question to review.

Combined with spaced reviews, this plan covers the two techniques most strongly supported by research.

Common self-testing mistakes

• Checking the answer too soon. Give yourself a few seconds to really think before flipping the card.
• Only retrying questions you already got right. The biggest gains come from the ones you still get wrong.
• Memorizing the answer choice instead of the reasoning. Shuffle the answer choices or rewrite the question.
• Saving tests for the night before. Self-testing works best when you repeat it over several weeks.

Sources: Roediger and Karpicke (2006), Psychological Science; Karpicke and Blunt (2011), Science; Dunlosky and colleagues (2013), Psychological Science in the Public Interest. Updated October 2026.

Frequently asked questions