Intelligent People Never Use Highlighters. Here’s Why

Added: 2026-05-18

[00:00:00]I've wasted hundreds of hours of my life, time that I will never get back just highlighting things. These are my notes from medical school. Look at this.

[00:00:07]Just pages and pages of endless highlighting. And I am so glad that I realized how useless this thing is before I graduated and became a working professional. Because as a learning coach, when I go out and do workshops with business owners and accountants and engineers, I see that they are still wasting time trying to learn by highlighting. But there is really only one way to use a highlighter for learning that is not a complete waste of time. Only one. And in my nearly 15 years of coaching across thousands of people, I don't think I've ever seen someone use a highlighter in that way.

[00:00:37]So, in this video, I'm going to explain why you should probably just throw your highlighter away. But if you want to keep it, how you need to change the way that you use it. Now, first of all, you need to understand that highlighters were never invented for learning.

[00:00:50]Highlighters were invented by this guy called Francis J. Han in 1963 by accident as he was trying to create a non-permanent marker for his children.

[00:00:58]And when he sold it, it was marketed as a design tool to emphasize important words in sales copy like the word refund or free sample. This is before digital advertising, so everything was still on paper. By the 1970s, using a highlighter became the go-to method for emphasizing things that are important, and it sort of just trickled its way into people using it for learning, too. But what you have to understand is that using a highlighter is less effective for learning than watching paint dry. And I mean that literally. There was a meta analysis that looked at a bunch of different learning methods. And one of the methods was something called wakeful rest. Wakeful rest means basically just doing nothing while being awake. So one of the studies actually had participants stare at a wall for 10 minutes. They would learn something new and then stare at a wall. And wakeful rest had a small to moderate positive effect. The idea is that after you learn something, when you just let your brain kind of just do nothing, it just replays and strengthens those new connections. And they found that just staring at a wall produced a hedges G value of 0.448.

[00:02:00]So for reference, a effect size of 0.2 would be considered small and then up to 0.5 is considered medium and then uh 0.8 is considered a large effect. On the other hand, highlighting produces an effect size of essentially zero. So, when I say that highlighting is useless, I really mean it. There's not many things that you can do that is more useless than just highlighting as you learn. Because you can just do literally nothing and it would be better than highlighting. And yet, across the last 20 years of surveys, almost every single major survey has found that highlighting is one of the most common learning methods that are used by people all across the world. Depending on the study, between 50 to 80% of people use highlighting as one of their go-to learning methods. And we're not just talking about students either. As a learning coach, where I work with both students and professionals, I find that most professionals have the same learning habits that they developed during the school years. They just carry those same methods forward and basically have the exact same problems in just different contexts. In fact, the problem with highlighting for working professionals is actually even worse than for students uh for reasons that I'll explain later in the video. But why is it so bad? And if it's really that bad, why is it so common? If I told people that a great learning method is to slap yourself in the face every time you read something, people would stop doing that because they would realize it hurts and isn't effective. So then why with 50 years of research telling us that highlighting is a waste of time, do we still do it? And the answer is that it's because it feels useful and that is because our brain is really bad at determining whether something is truly useful or not. What we're talking about here is something called the illusion of fluency. And this is a problem not just for highlighting, but almost every learning method that we use. The illusion of fluency is when your brain confuses the ease of processing information with the quality of learning that information. Here's what happens inside your brain when you're trying to read through a dense piece of uh technical documentation or reading information from a textbook or watching a video. All of this data, all of this raw information is coming into your brain and your brain is trying really hard to process this information. And as it processes this information, it encodes that information inside our long-term memory. But the problem is there's no way for your brain to accurately know how much of this information was actually encoded. Our brain cannot ping our memory store and our memory store says, "Oh, it's 72% encoded." And so instead, your brain has to figure out how much processing has actually occurred using these indirect cues. And one of the most powerful cues is how fluent it feels. Fluency is basically how easy, how effortless the information seems to flow in. And so when you're reading something that you know a lot about, it's really easy to understand. It's easy to process. It feels fluent. Whereas if you read something dense and technical and new, you're getting stuck on every sentence.

[00:05:07]You're rereading paragraphs. It doesn't feel smooth and effortless at all. The information is not flowing in. and it feels more like you are forcing the information inside your brain and so that we feel as low fluency. The issue is our brain's judgment of fluency is influenced by a bunch of different factors that have absolutely nothing to do with the actual quality of memory that is formed. For example, studies show that larger font size and higher volumes of speaking are associated with higher levels of fluency. But neither of these things actually translate through to higher quality or more durable memory. And as you may have guessed, when we highlight something because it makes it visually pop out of the page, it makes it feel more fluent. And so we misinterpret that feeling of fluency with actual meaningful memory formation taking place. And the effect is actually kind of crazy because I can demonstrate the same thing using something like this, which is a gibberish map made up of basically nonsense information. And I can simulate the same thing that highlighting does just by circling things with different colors. So if I just choose to circle this like this and I make things just look visually as if it pops out on the page a little bit more. You can actually feel that for some reason it looks more organized than it did before. Even though it actually means nothing, it just feels less overwhelming because there's color. And so in reality, when you do lots of highlighting, which I used to do that, what you're actually doing is that you're using highlighting as an emotional coping strategy, what's happening is that as you read through this page and you realize that this word is important and this word is important and this word is important, mentally each of those concepts is entering into our mind. And we know that these concepts are important and they're important because they're related together and they influence each other in some kind of way. And as more and more of these important concepts enter into our mind, we get more and more overwhelmed with all the different possibilities of how all of these concepts relate to each other. Now figuring out how it relates to each other, building what we call a schema mentally, this is actually what creates highquality learning. It is only when your brain is able to see how it connects together that that durable memory is actually formed. But at the same time, trying to figure out how this is all connected is very overwhelming.

[00:07:36]There's a lot of confusion involved, especially if you've got a lot you need to get through and you don't have much time. You don't have time to be overwhelmed. You don't have time to be confused. And it doesn't feel good feeling overwhelmed and confused. And so, what do you do as a response to that uncomfortable emotion? You pick up your highlighter, you highlight a few things, you trigger that fluency, and you trick your brain into thinking it's figured it all out. And now we feel good. We're not overwhelmed anymore. We're not confused anymore because we basically just stopped asking the questions that made us feel confused. But here's a question.

[00:08:10]If highlighting essentially shuts off our brain, tricks it into thinking it's figured everything out and it's learned it, then wouldn't most people realize that the way that they're learning, even though it feels easy, is totally ineffective? And the answer based on learning science research is actually no. And this is actually the second major reason on top of the illusion of fluency that makes highlighting so common. And this is something that's called the misinterpreted effort hypothesis. The misinterpreted effort hypothesis is a phenomenon that's been observed in learning science research where people mistakenly interpret high levels of effort as being equivalent to not effective. So if they use a learning method and it feels very effortful, then they judge that it must not be very effective. It's almost like the reverse of the illusion of fluency. The illusion of fluency is saying that when something feels easy, it means you've learned it.

[00:09:06]The misinterpreted effort hypothesis says that when it doesn't feel easy, you're doing something wrong. And the combination of these two effects is really problematic because like I said, trying to figure out the schema, how everything connects, this is inherently confusing. It inherently involves mental effort to try to figure it out. And so every single learning strategy that is effective involves higher levels of effort. And if you believe that higher effort equals not effective, that means that anytime you use any effective learning strategy, you would say this is not working and you would stop using it.

[00:09:42]And this is also the reason why earlier I said that the problem of highlighting is actually worse for busy professionals. This is because professionals tend to be more time poor.

[00:09:52]So when they're trying to learn through a bunch of stuff that they need to complete for work and they don't want to spend every evening just reading through documentation or keeping up with the industry, they are heavily incentivized to find a method that is faster and easier, which also usually means less effective. But because most people don't realize the illusion of fluency and the misinterpreted effort hypothesis, when they use these strategies and their memory is not good and they've forgotten half of what they've learned a few days later, they just assume, I must have a poor memory. I must not be working hard enough. I'm just not as smart as some other people. They don't realize that their method of learning is actually sabotaging them. And so with all of this in mind, if you still want to be highlighting, how do you actually make it work? What is the one way that you can use a highlighter that's not a waste of time? Well, the first thing is to realize that you're probably also wasting time in other areas as well. If you are using a highlighter very often as a learning method, there is a very high chance that your other learning methods can also be improved. And so sort of as a prerequisite to learning how to learn effectively, you actually have to understand what effective versus ineffective learning even looks like to begin with. And the best way to understand this in a short period of time is going to be to join my newsletter. I think that's the first time I've used my highlighter in like 10 years, but I really wanted to emphasize how easy it is to join my newsletter and just learn more about what effective and ineffective learning looks like. the idea of passive versus active learning, which is really what I'm talking about in this video. This is just one of the foundational concepts that's taught in my newsletters. It's totally free to join. It comes into your inbox every single week. And at the bottom of every newsletter, there's a practical strategy or a takeaway for you to work on and practice during that week. And just by practicing that, you're going to save time way more than the few minutes that it takes to just read through the newsletter. So, if you like the idea of not unnecessarily wasting time, then you should check out my newsletter. I'll leave a link for you to join in the description below. Now, beyond that, here's how you make highlighting actually work for you. We start by understanding that highlighting by itself isn't doing anything. So, the only way to make it effective is by bolting on an effective strategy onto your existing habit of highlighting. So, I'll show you what that looks like. So, I've got this old biology textbook here, uh, which I bought secondhand many, many years ago, which someone had already highlighted in because I dare not highlight a brand new textbook and ruin it. And I show you how I would apply an effective version of highlighting. So, let's say I'm learning this page here, which is titled mechanisms of gene transfer and genetic recombination in bacteria. What we're going to do is that this highlighter is going to become a gate. It is a gate to deeper thinking.

[00:12:33]And every time you want to pass through this gate of highlighting, you need to pay with deeper thinking. So let's say that I'm reading through this page here.

[00:12:40]So I'm just going to read this as I normally would. And then I'm going to catch myself just before I start highlighting the page. So reading bacteria different from ukariots and the mechanisms used to bring DNA from two individuals together in one cell. In ukarotes, the sexual processes of meiosis and fertilization combine DNA from two individuals in a single zygote.

[00:13:01]Okay. So, I feel like I wanted to highlight this this part of the sentence here that said in a single zygote like that just felt to me like some kind of key word that I normally in, you know, in my previous life, I would have just mindlessly highlighted. But now with this modified strategy, I'm using this as a gatekeeper for more effective learning. And so, one change I'm going to make is before I highlight, I'm going to ask myself, is that really the best thing to highlight in this paragraph? I want to be ruthlessly selective in what I choose to highlight. I don't want to have that, you know, basically painting over my notes with a highlighter kind of effect. I want to be really, really careful about what I choose to highlight. And by asking myself this question, is this the best two words to highlight? I'm now forcing my brain to do comparison. This is called higher order learning. I'm thinking about the concept of a single zygote. And I'm thinking, was that more or less important than highlighting the word meiosis or fertilization? Or do I even need to highlight anything at all? Maybe there's another thing later in this paragraph that's more important to highlight. And so this is my brain engaging in that deeper thinking that helps to connect the ideas together and form that schema, aka that durable memory you're actually going to hold on to and that you can use. And so what I might decide after reading through this paragraph is that you know what actually if I'm being ruthlessly selective, I don't need to highlight anything on that page. And guess what? even though you didn't highlight anything just because you forced yourself to really think about that carefully already your retention and the quality of your memory has gone up and that's the thing about learning sometimes it doesn't look like anything because most of what learning is happens in the brain now some of you will feel very uncomfortable with not highlighting anything like man I just read a concept I got to highlight something otherwise you have this anxiety that you're going to forget it but remember the highlighting is not doing anything for you in the first place. That feeling of security you're getting, that security is fake. It's that illusion of fluency coming to your side, patting you on the back, saying, "Shh, it's okay. There's no more confusion now. There's no need to be overwhelmed while it's actively stamming you in the back." So, don't fall for it.

[00:15:09]Remember, it would be better to do nothing at all and just stare at a blank wall than it would be to highlight mindlessly. So, now let's go through and we say we do want to highlight something. So let's say I decide that this single zygote I am going to highlight it. It truly is what I think uh the most important thing to highlight in this concept and it's worth highlighting. Once I've highlighted it, I'm going to pay that deeper thinking cost one more time. And I'm going to do that by pausing after I've highlighted and just asking questions. Really forcing myself to be curious about this.

[00:15:43]I might ask myself, why is it a single zygote? What would it be like if it was multiple zygot? Would this work with more than two individuals combining together? Could it be four or five different bacteria that uh recombine into a single zygote? I'm actually forcing myself to ask questions about this. Now, trust me, I have no natural curiosity about this subject. But by forcing my brain to ask these questions, I'm forcing my brain to probe out from the schema to try and look for other connections actively. And that means that when I read through the rest of the text, there are more places that that information can catch into and be consolidated inside that schema. I'm actually forcing it to grow and reach out at new information. This draws on a principle in learning science which is called priming, which basically gets your brain to think a little bit more actively about what it's going to learn soon. And by getting your brain a bit more active later, when it absorbs that information, it's able to turn that into a durable memory much more easily.

[00:16:43]Priming is also a strategy that allows you to increase your fluency, making it feel easier and smoother to absorb information in, but it does it in a productive way that actually translates through to better memory. And so that is what you can do to make a highlighter more effective. Take an existing strategy that involves deeper thinking and then bolt it on to the act of highlighting before, during, after, before, during, and after. It doesn't matter. What I've given you is just an example. But you have to do that. If you do not attach a more effective thinking strategy to the use of your highlighter, you may as well just throw it away. And for those of you who have gotten to this point in the video, but you're a bit hesitant to attach those extra strategies because it's going to slow you down. I want you to remember the biggest waste of time comes from being efficient at something that you should never be doing. Even if it takes you three times longer to get through the page, your ability to turn that information into memory and usable knowledge is probably three times faster. And measuring your efficiency by how many pages you can get through a minute is the mindset of a printer. And if you want to learn one strategy to help you with this deeper thinking that you can bolt on to your highlighter or just replace it completely, then check out this video here where I teach you how to think on paper. It is one of the most useful and game-changing skills for clearer thinking and faster learning.

[00:18:09]So, check out that video.