Why Do We Forget What We Read? — 3 Steps to "Memorable Reading" Based on Learning Science
Theme: Memorable Reading Techniques — 3 Steps to Output-Oriented, Brain-Science-Based Reading
"What was that business book I read last month about again?"
Being unable to recall almost any of the content—those who consider themselves avid readers have likely experienced this feeling. You spent time reading it, yet nothing stuck. The cause may not be your memory, but rather the "way you read" itself.
Over the past decade or so, cognitive science has revealed through numerous experiments how we can learn in a way that ensures information sticks. This article breaks down those findings into three steps: "Before Reading, During Reading, and After Reading."
Actually, many people's "go-to" methods are ineffective
First, a bit of a hard truth.
Methods we often use when reading, such as "highlighting important parts" or "re-reading," have been found to be not highly effective according to learning science.
In 2013, American cognitive psychologist Dunlosky and colleagues conducted a large-scale review of 10 learning methods and ranked them by utility (Dunlosky et al., 2013, Psychological Science in the Public Interest). As a result, **rereading, highlighting, and summarizing** were classified as having "low utility." Despite many students relying on these, they do not consistently improve performance.
On the other hand, the only two methods evaluated as having "high utility" were **practice testing (retrieval practice) and distributed practice (spaced review).**
In short, the key to memorable reading is not "reading it again," but "recalling" it.
Why does "recalling" help with memory?
This phenomenon is called the "testing effect" or "retrieval practice."
There is a representative experiment. In 2006, Roediger and Karpicke had students learn a text; one group "repeatedly read" it, while the other group "took a test (recalled)" after reading (Roediger & Karpicke, 2006, Psychological Science).
In the immediate results, the "repeated reading" group performed better. However, after 2 days and 1 week it reversed, and the group that practiced "recalling" had significantly higher memory retention.
This effect has been repeatedly confirmed in subsequent meta-analyses. In Rowland's summary of 159 studies (2014, Psychological Bulletin), the effect size of testing over restudying was g=0.50. Adesope et al.'s (2017) meta-analysis also showed a robust effect with an average g=0.61. Moreover, recalling through short-answer or free-response questions was more effective than multiple-choice.
This can also be explained by how the brain works. Reading expert Maryanne Wolf argues that in deep reading, "elaboration"—connecting what you read to your existing knowledge—deepens understanding and memory (Wolf, Reader, Come Home, 2018).
3 Steps to Memorable Reading
Let's apply these scientific findings to your reading starting tomorrow. The point is to divide roles into "before, during, and after" reading.
Step 1 [Before Reading] — Set a "Question" before opening the book
Instead of jumping straight into the text, write down "what you want to gain from this book" as a single question.
Example: If you want to "improve meeting facilitation," ask "What techniques can I use in tomorrow's meeting?" Once the goal is set, the brain becomes more attentive to relevant information, and reading turns into a "search for answers."
Step 2 [During Reading] — Use "Your Own Words" Instead of Highlighting
Highlighting has low utility, but writing in the margins (marginalia) is a different story.
"This can be used in that situation at my job," or "This argument is the opposite of a book I read before"—leaving notes that connect to existing knowledge in this way is an act of elaboration itself. The key is not to be satisfied with just drawing lines.
Step 3 [After Reading] — Close the Book and "Recall"
This is the most important part. Once you finish reading, keep the book closed and try to recall and write down the content.
Specifically, write down the "main points, impressions, and what to do tomorrow" in 3 lines in a notebook. To increase the effect further, as recommended by psychiatrist Shion Kabasawa, repeat the output by talking to others, introducing it on social media, or writing a book review.
The timing is also scientific. Based on the nature of the hippocampus, which temporarily stores memories, it is said that recalling and outputting about three times within two weeks of the initial input makes it easier to transition to long-term memory (Shion Kabasawa, "Reading Techniques That You Won't Forget After Reading," 2015 / "The Output Encyclopedia," 2018). Try making "use it 3 times after reading" your motto.
There is value in the act of "continuing to read" itself
Finally, some good news unrelated to reading techniques.
A study tracking 1,962 elderly people in Taiwan for 14 years showed that people who have a habit of reading at least once a week have a significantly lower risk of cognitive decline, regardless of their educational background (Chang et al., 2020, International Psychogeriatrics).
There is no need to feel pressured to memorize everything perfectly. Continuing to read is an investment in your brain in the long run.
Summary — "Recalling" is the Key to Everything
Memorable reading techniques are not special speed-reading skills or expensive tools.
Before reading: Set a question
During reading: Connect to what you know in your own words
After reading: Close the book, recall, and output 3 times in 2 weeks
Stop "trying hard" to reread or highlight, and shift your focus to "recalling". Just by doing that, your reading will change from "disappearing information" to "usable knowledge." Start by writing down the book you read today in 3 lines.
References
Academic Research
Roediger HL, Karpicke JD. (2006) "Test-enhanced learning: taking memory tests improves long-term retention," Psychological Science 17(3):249-255. https://pubmed.ncbi.nlm.nih.gov/16507066/
Dunlosky J, Rawson KA, Marsh EJ, Nathan MJ, Willingham DT. (2013) "Improving Students' Learning With Effective Learning Techniques," Psychological Science in the Public Interest 14(1):4-58. https://journals.sagepub.com/doi/10.1177/1529100612453266
Rowland CA. (2014) "The effect of testing versus restudy on retention: A meta-analytic review of the testing effect," Psychological Bulletin. https://doi.org/10.1037/a0037559
Adesope OO, Trevisan DA, Sundararajan N. (2017) "Rethinking the Use of Tests: A Meta-Analysis of Practice Testing," Review of Educational Research 87(3). https://doi.org/10.3102/0034654316689306
Chang YH, Wu IC, Hsiung CA. (2020) "Reading activity prevents long-term decline in cognitive function in older people," International Psychogeriatrics. https://pmc.ncbi.nlm.nih.gov/articles/PMC8482376/
Wolf M. (2018) Reader, Come Home: The Reading Brain in a Digital World, HarperCollins. (Explanation regarding deep reading and elaboration) https://seis.ucla.edu/news/maryanne-wolf-deep-reading-a-tool-for-attaining-empathy-critical-thinking-skills/
Practical Information
Shion Kabasawa, "Reading Techniques That Ensure You Don't Forget What You Read" (2015) / "The Output Encyclopedia" (2018) Key Points (flier book summary) https://www.flierinc.com/summary/1745
STUDY HACKER, "3 Summarization Techniques to Do After Reading So You Don't Forget the Content" (2025) https://studyhacker.net/after-reading
This article is intended to introduce learning methods and health information; individual results may vary.