In 2013, researchers John Dunlosky and colleagues published a landmark review in Psychological Science in the Public Interest. They evaluated 10 of the most commonly used study techniques on the basis of how well each produced long-term learning. The results were striking. The two techniques students use most, re-reading and highlighting, received the lowest effectiveness ratings of any method reviewed. The two techniques with the highest ratings, practice testing and distributed practice, were the least used.
This is not a minor gap between good and great. Students who use low-yield techniques for 6 hours routinely underperform students who use high-yield techniques for 3. The following 7 myths cover the most common habits that feel productive but consistently fail in research. Each one includes the mechanism behind why it fails and a direct replacement.
Quick Answer
The most pervasive study myths are: learning styles (visual/auditory/kinesthetic) affect how you should study (no evidence), re-reading is effective (it produces familiarity, not recall), highlighting improves retention (it does not), and you can effectively multitask while studying (divided attention consistently reduces encoding). Research debunks all four.
Myth 1: Re-Reading Your Notes Is Effective Study
Why re-reading feels like learning but isn't
When you re-read your notes, the material starts to feel familiar. That familiarity registers as progress, which is why re-reading is so appealing. The problem is that familiarity is a recognition signal, not a retrieval signal. On an exam, you are not asked to recognize information in front of you. You are asked to retrieve it from nothing. Re-reading trains the wrong skill entirely.
The mechanism: each time you read something passively, you strengthen a recognition trace but do almost nothing to strengthen the retrieval pathway that exam performance requires. Research by Roediger and Karpicke found that students who re-read performed far worse on tests given one week later compared to students who practiced retrieval, even though re-readers felt more confident going into the test.
Do this instead: Close your notes and write down everything you remember about the topic on a blank page. This is called free recall or a brain dump. What you cannot write is what you still need to study. What you can write is already on its way to long-term storage.
Students who practiced retrieval instead of re-reading retained 50% more material one week later, yet reported feeling less confident than their re-reading peers going into the exam.
Myth 2: Highlighting Important Passages
Why highlighting produces almost no learning
Highlighting requires you to make one decision: does this sentence seem important? That single decision is not deep processing. You are not encoding the content, connecting it to prior knowledge, or attempting to retrieve it. You are just marking text.
The result is a page full of yellow marks and a memory that contains almost none of what those marks covered. Dunlosky's 2013 review rated highlighting as low utility after finding that students who highlighted their textbooks performed no better on tests than students who simply read without marking anything.
Do this instead: After reading a paragraph, close the book and write one sentence from memory that captures the main idea. You can also turn each heading into a question before reading, then answer it from memory after. Both of these force processing rather than passive marking.
Myth 3: Studying in Long Marathon Sessions
Why massed practice underperforms spaced practice
Studying 4 hours in a single block feels efficient. You cover everything in one sitting, you feel the momentum of staying in one subject, and you finish feeling like you've done the work. The research disagrees.
Working memory has a hard capacity limit. After roughly 45-90 minutes of intensive cognitive work, it begins to saturate and learning rates drop. More importantly, massed practice, studying the same material all at once, produces inferior long-term retention compared to spaced practice, studying the same material across multiple sessions separated by time.
The mechanism is consolidation. After a study session, your brain needs time to transfer information from temporary to long-term storage. Sleep is especially important here. Three separate 90-minute sessions across three days give your brain three consolidation cycles. One 4.5-hour session gives you one, and the last hour of that session is reaching a brain that is already saturated.
Do this instead: Break your total study time into sessions across multiple days. Review material from the previous session at the start of each new one. A schedule of study on Day 1, brief review on Day 2, and fresh retrieval on Day 4 will outperform a single 6-hour block every time.
Myth 4: Multi-Tasking While Studying
Why music with lyrics, TV, and a nearby phone all hurt
The human brain does not multi-task. It switches between tasks extremely rapidly, which creates the illusion of simultaneous attention. Each switch carries a cost: time to reorient, a drop in working memory availability, and a reduction in the depth of processing for the material you switched away from.
Research from Gloria Mark at UC Irvine found that after a single interruption it takes an average of 23 minutes to return to the original level of focus. A phone notification mid-study session, even one you choose not to respond to, resets that clock.
Music with lyrics creates a specific type of interference. Language processing uses the same cognitive resources as reading comprehension and verbal reasoning. When your brain is parsing song lyrics while trying to understand a textbook paragraph, both tasks suffer. See our guide on studying with music for the full breakdown. This is not preference, it is architecture.
Do this instead: Phone in another room or on airplane mode. If you need background sound, use instrumental music or brown/white noise at moderate volume. Study in a location where spontaneous social interruptions are unlikely. Single-task every session.
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Myth 5: Cramming the Night Before Means You Know It
Why cramming destroys retention and sleep makes it worse
Cramming works, briefly. If you load information into short-term memory the night before an exam and walk in four hours later, you can often retrieve enough to pass. The problem surfaces when that exam is worth partial credit toward a final, when you need the material for a subsequent course, or when the test is cumulative.
Research consistently shows that material crammed under sleep-deprived conditions shows steep decay within 24-48 hours. One week after a crammed exam, students retain a fraction of what spaced learners retain on the same material. More acutely, a night of poor sleep before an exam compounds the problem: Walker's research found that sleep deprivation reduces the brain's ability to retrieve memories by roughly 40%.
The cruel irony is that cramming requires you to sacrifice the very thing, sleep, that determines how well you can retrieve what you crammed.
Do this instead: Do a light review session the night before an exam, not a cram session. Spend 30-45 minutes doing active recall on the highest-yield material, then stop and sleep. The sleep will do more for your exam performance than another 3 hours of reviewing would.
Myth 6: Re-Doing Your Notes Neatly Is Productive
Why transcription without recall is just busy-work
Re-copying your notes into a cleaner format is one of the most seductive low-yield habits in studying. It feels productive because you are engaged, sitting at your desk, writing academic content. The problem is that copying text, even your own text, does not require you to retrieve anything. You are looking at the source and transcribing. That is data transfer, not learning.
The act of writing is not inherently educational. The act of retrieving what you know without access to a source is. Students who spend an hour neatly re-copying their lecture notes walk away with a beautiful notebook and the same amount of retention they had when they started. Students who spend that hour reconstructing their notes from memory on a blank page walk away having identified gaps and reinforced what they actually know.
Do this instead: After a lecture, wait a few hours and then try to reconstruct the key points on a blank page without looking at your notes. Check against your original notes only to identify what you missed. Spend any remaining time on the gaps, not the parts you already recalled correctly.
Myth 7: More Hours Always Means Better Grades
Why method matters more than duration
The assumption that grade outcomes are primarily a function of time invested is wrong, and it is the belief that keeps students grinding through 8-hour study sessions that produce mediocre results. Time matters, but technique multiplies it.
Consider two students preparing for the same exam. Student A spends 8 hours re-reading and highlighting. Student B spends 4 hours doing active recall, spaced retrieval practice, and practice tests. The research is consistent: Student B performs better on the exam, retains more material a week later, and is less burned out walking into the room.
This is not an argument for studying less. It is an argument that the return on each hour of study varies enormously depending on what you do during it. Time is a necessary input. It is not the key variable.
Do this instead: Before adding another hour of study time, ask whether you can improve the quality of the hours you already spend. Replace one re-reading session with active recall. Replace one highlighting session with practice testing. The grade impact of that switch is typically larger than adding an extra hour of low-yield study.
What to Do With This Information
Identifying bad habits is only useful if you replace them with something better. The research on learning is not complicated. Active recall, spaced repetition, practice testing, and adequate sleep account for the majority of what separates students who retain material from those who forget it.
You do not need to overhaul your entire study routine at once. Pick one habit from this list that you currently rely on and replace it with the alternative listed below it. Run that replacement for two weeks across a single course. The difference in exam performance will make the other changes obvious.
The most important shift is conceptual. The goal of studying is not to feel like you have covered the material. The goal is to be able to retrieve it without any prompts on an exam. Every technique you use should be evaluated against that standard. Re-reading does not meet it. Active recall does.
The bottom line on study habits
The gap between students who get good grades and those who do not is not usually effort. It is method. Re-reading, highlighting, marathon sessions, multi-tasking, cramming, note transcription, and raw hours are all techniques that feel productive and consistently underperform in research. Active recall, spaced practice, and sleep are the high-yield replacements. Switching is not about working harder. It is about stopping work that does not pay off.