Studying hard but still forgetting? 3 methods that don't work well

You reread the textbook again and again. You made neat, organized notes. You highlighted every important part. And yet, on test day, it just won’t come back to you. Sound familiar?

Kosuke Yasukawa is a doctor of internal medicine and infectious diseases working in the United States. In his book The Best Way to Study, Based on Scientific Evidence (Japanese title: 『科学的根拠に基づく最高の勉強法』), he explains that many of the study habits we take for granted aren’t actually that effective. Drawing on a wide range of learning research, the book introduces both the methods that work poorly and the ones that work well.

In Part 1, let’s look at three methods the book describes as less effective.

1. Rereading

This is probably the most familiar way to study. The book mentions a survey at one American university in which more than 80% of students said they reread material to prepare for exams.

But simply rereading is known to be less effective for memory than other methods.

The trap is that rereading makes the material feel familiar. And when something looks familiar, you start to feel like you understand it, or that you’ve already memorized it. But recognizing something when you see it and being able to recall it without looking are two completely different skills.

2. Copying and summarizing notes

Finishing a beautiful set of notes makes you feel like you’ve really studied, doesn’t it? But when you copy text straight from the textbook or tidy things up with colored pens, your hand is often moving while your brain isn’t doing much.

It takes a lot of time, but not much of it sticks. Once making notes becomes the goal in itself, the results stop matching the effort.

3. Highlighting

Highlighting is easy, and it gives you a small sense of accomplishment. But drawing a line doesn’t, on its own, make a memory stronger.

Worse, as you highlight this and that, the whole page turns colorful, and it actually gets harder to see what really matters.

Why do we keep choosing methods that don’t work?

All three have one thing in common: they’re easy, yet they feel productive. Reading, copying, highlighting — none of them put much strain on your brain, so it’s easy to feel like you’re getting somewhere.

But whether something stays in your memory has little to do with that feeling. If anything, what you remember longest is what made you think hard enough to struggle a little.

What this looks like in language learning

The same thing happens when you study English or Japanese:

• Flipping through a vocab book and thinking, “Yep, I know that one” → rereading
• Writing each new word ten times in a notebook → copying
• Highlighting example sentences in your textbook → highlighting

None of these is a waste of time, but on their own, they rarely turn into knowledge you can actually use.

Don’t drop them — add to them

That said, I don’t think you need to give these methods up completely. Reading something once to get the big picture, or marking spots you want to review later — used that way, they’re genuinely helpful.

What matters is not stopping there. So what should you add? In Part 2, we’ll look at the methods the book identifies as highly effective.