Why You Should Only Read Tedious, Long, Difficult, Redundant Books

The neuroscience behind why reading books that don't cause you headaches is a waste of time.

According to Art Kohn, who has a Ph.D. in cognitive science, we forget 50% of the data we see or hear within an hour. We forget 70% of it after one day and 90% after a week.

Assuming this is true, we, on average, remember 25 pages worth of content from a 250-page book after a week. "Remember" is defined as the capacity to recall about 10% of the general meaning of a book, not as your odds of rehearsing 10% of the pages word-for-word. If you have an average reading speed of 238 words per minute and the 250-page book has 90,000 words, it will take you 6.3 hours to read it. Out of these hours, only 0.63 led to learning. The rest were more or less wasted.

I say "more or less" because you don't know the parts of a book you will value the most until you read all of it. So your 10% of value might be at the beginning, middle, or end. But it's time wasted, as you won't remember what you read during the remaining 5.67 hours. Almost six fewer hours to write, play with your kids, or read this newsletter.

Reading tedious, long, difficult, and redundant books (TLDR)¹ can get you part of those hours back. These books make your brain grasp information faster and recall more of it. The best part is you don't have to do anything other than reading—no Pomodoro sessions, spaced repetition, or writing about the subject you read. I know it sounds counterintuitive, but allow me to explain.

The TLDR-ness of a book is subjective and variable.

What you know, believe, and are open to exploring defines the TLDR-ness of a book:

• Reading about the theory of how magic mushrooms developed human consciousness might be tedious for an evolutionist. Even if they might learn something new, their beliefs push them away from reading about it. But, to me, it's a topic worth exploring.

• A 1000-page book might be long for a designer but not for an academic

• A book on how to knit might be more difficult for a philosopher than Schopenhauer's The World as Will and Representation. 

• For someone, a book that repeatedly talks about a few concepts might be redundant. But it might not be for me if I enjoy being reminded of previous information.

TLDR-ness is also variable. As you read more of these books, the threshold to consider one as TLDR rises. You get used to longer books, you understand more concepts, so it's easier to link new ones to old ones, and you are more open to exploring new subjects.

Thus, to benefit from the following memory benefits from reading these books, you must read what's TLDR to the current you.

TLDR books help your brain store information easier and for longer

Encoding is a brain process that creates a mental representation of what you saw, heard, or touched. Neuroscientists call these mental representations traces. 

Our brains store traces in our short-term memory. They are meaningless patterns containing details of what happened and when it happened. Think of traces as old household items you put in a storage facility. You know they exist but do not know what you can do with them yet. So you store them. You might use them or not. Learning a novel topic leaves traces in our brains that we will mostly forget. 

Only 0.63 of the hours you spend reading a 250-page book lead to learning. You waste the remaining 5.67.

One way to help your brain store traces in your long-term memory is to apply what you learned from a book in real life. When we use what we learn, we help our brain store what we read for longer. Apply means doing anything with the knowledge you read:

• Teaching a class

• Writing an essay

• Changing a process at work

This use of knowledge must happen before the trace vanishes. 

This is difficult to do with short, simple books as you read them fast. I can finish a 250-page book in six hours. Six days from beginning to end if I read one hour daily. If I do, I'll have seven days from that moment forward to apply all that I've learned. Even if the information is straightforward, seven days is not enough time to apply it. Some knowledge might persist for a long time, maybe decades, but most won't.

It's easier to encode information from a longer, more complex book. Your reading pace will be slower because you will take more time to read each page. So, reading one hour daily, you might only get to 25% of a 500-word book on week one. On week two, as you read the next 25% of the book, you will only have to apply 25% of the book's learnings, not 100%.

A counterargument is that TLDR books often pack more data into each chapter. The 25% of a book you consider TLDR is more challenging to grasp than the 25% of a simple book. So you will read fewer words, but you will have more information to apply per chapter.

This is true, but our brain benefits from the raised difficulty that TLDR books pose. It is easier for it to store information that is challenging to grasp and remember. This is because forgetting is key to making a trace part of your long-term memory. When you struggle to recall information, the trace strengthens. As long as you retrieve it, says psychologist Henry Roediger, the more likely you will recall the information in the future.

Therefore, it is easier to understand a simple concept than a complex one. But, the lack of struggle to grasp it can reduce your chances of forgetting it in the short term and storing it in your long-term memory.

The need for difficulty explains why you can't read a simple book slowly to have more time to apply the information. You will recall more of it if you read it six times. But that'll make the material easier to grasp, giving up on the benefits that come from learning challenging ideas.

The length of TLDR books also aids the brain in consolidating what you read.

Consolidation is the brain's process of structuring traces via sleep and association with knowledge from the past. The longer the book is, the more information you have to connect. You can link a concept from the second chapter with those from 20 more. 

For example, let's say you have read ten 100-page straightforward evolutionary psychology books. And I've read ten 1,000-page TLDR books. So by the 11th book, I'll have at least 1,000 pages to connect to the new material (10% out of 10,000), while you have 100.

You might think, "wouldn't I have the same amount of links to you if I read a hundred 100-page books?" No, because you would still have had less time to apply what you read than I did. 

Remember. The faster you read, assuming you are always reading at least one book, the less time you have to apply what you learned.

Read fewer books that are not tedious, long, difficult, and redundant 

A long, complex book will give you more headaches than a short, simple one. It might be tedious if it explains one concept repeatedly. But you are also more likely to remember it because of how your memory works.

Read The Wealth of Nations, not Freakonomics. Maps of Meaning, not 12 Rules for Life. Deceit, Desire, and the Novel, not Wanting. On the Origin of Species, not Sapiens. The Beginning of Infinity, not The Alchemist. A Treatise of Human Nature, not How to Win Friends and Influence People. Crime and Punishment, not The Hunger Games.

Read what's challenging today, so it's easy to remember it for the rest of your life.

1. I'm aware that tl;dr is an abbreviation for too long, didn't read. This is not a play on that acronym nor a reference to its meaning. I went with TLDR to present a new concept under a known acronym so it's easier for you to recall this essay.