A few times in the past, I've mentioned something called Critic Fatigue. It's a concept where you don't want to give a critic a chapter beyond a certain word count because it'd be too difficult for them to write criticism for so much. This isn't simply a critique size thing, but also a limit in the amount of attention a critic can focus on before they simply become overloaded. The number is typically considered to be about 3000 words. A critic can only handle about 3000 words at a time to write a critique. Any more, and they start to miss things, either from being unable to focus long enough or from having too much to say.
This same kind of concept can be transferred over to readers in something I like to call reader's fatigue. Please note that this isn't an official "English" thing, merely an observation I've made from my own experiences. It's basically the same concept as a critic fatigue, but rather than focus on what someone needs to retain to write a critique, it focuses on what someone needs to hold on to so that they can enjoy a scene at the maximum value.
But Dorian, you might say, I can sit down and read a book all night. I'll read 100,000 words in one sitting. How can you possibly say that a reader would grow fatigued in the span of a single chapter?
My explanation for that comes from another chapter. When I spoke of paragraphs and what they meant for a book, I've often tried to compare them to acts in a play. A single word can conjure up a single static image. A sentence can put one or more static images in motion. By the time you reach a full paragraph, you have an entire thought or idea. This can be a description of something, an action, or an event. It's just something playing out. Combine all of the paragraphs together, and you end up with a chapter. That chapter represents a scene in a play. If you combine all the scenes, you end up with all the chapters of your book, which makes up your entire story. Therefore, to understand writer's fatigue, you need to see a chapter of a book like you'd see a single scene within a play.
Every scene unfolds in a very particular way. Usually, you'll establish the location and setiing the scene unfolds, and perhaps the people who will be partaking in this scene. Scenes can fluctuate quite a bit. There are long scenes and short scenes. There are exciting scenes and boring scenes. Every scenes is different in its own way, and when you combine them all, you have a play. You, as a viewer, can certainly watch an entire play in one sitting without too much difficulty. However, what if an entire play was performed with only one scene? Would you be able to watch that?
In one scene, you never take a breath. The location never changes. The lights never go out. The curtain never closes. Your eyes are constantly on the actors, who are constantly pushing forward with the story. I'm just describing it, and already it feels exhausting. Now, apply that to the concept of reading a book. You'd never read a book that consisted of only one chapter (unless that book was very short) This is one way to see reader's fatigue.
Now, there is some good news. Readers fatigue is relative. A young teen would probably get exhausted a lot quicker than a seasoned reader. That's why there tends to be such a discrepancy between chapter sizes. A young adult book might write 2000-word chapters, while Tolkien can get away with 10,000-word chapters. Partially, this has to do with who your target audience is. Partially, this has to do with the expectations you have for your audience from beginning to end. Some of it even has to do with the mindset your audience is in when they read the story.
I pointed out several times in the past that you need to properly set up your environment and your reader's expectation. Chapter sizes are one way to do this. Properly listing your genres is another. Failing to properly give your readers the accurate expectations for your writing can contribute to writer's fatigue. If I went to a movie expecting to see a comedy, and what I got was a heartfelt drama, it would feel much longer and more tedious than I would had I known what I was getting into.
Now, reader's fatigue is something that doesn't always have to happen. It's very possible to avoid reader's fatigue with a dynamic and interesting plot. When a lot of things are happening, you find yourself reading longer. We've all been there where we wanted to read just one more chapter only to find us five hours later with half the book done. However, this does change from person to person, a book I can't put down can be horrifically difficult for you to even start.
Meanwhile, one of the biggest criticisms I've seen has always been the dastardly exposition. To most people, nothing builds reader's fatigue quite as quickly as laying our swaths of the plot without substance. A chapter that just tells you how each character is supposed to act will tire out and be less interesting to your audience than a chapter that shows you how each character acts within a plot interesting situation.
Likewise, I think there is an advantage for having a story progress. Perhaps this is a discussion for another day, but people will get far less fatigued when they feel like a story is going somewhere. I frequently have been reading a lot of long-winded web novels lately. I have to tell you when I reach a fluff chapter where two characters I don't care about engage in a fight or a long-winded dream sequence, or a sudden side quest that doesn't affect anything in the story, I quickly grow bored.
I've skipped entire story arcs because they don't serve to push the story in any direction or even provide characterization for the characters I care about. Reading a chapter that's not going anywhere, or worse, is a confusing mush of crap, is just tedious at best. This is an example of reader's fatigue at it's most obvious. When a work feels tedious to read, it's probably because it is, and frankly, a lot of the time, I just can't do it.
Take note of this if you're one of those writers attached to dream sequences. You string together random disconnected scenes of surreal prettiness while giving every item of focus some kind of subtle meaning. To you, it might feel like a mystery you hope your readers will figure out. The problem you didn't consider, however, is that your readers haven't read the story yet, and thus your symbolism literally means nothing to them at the point of the prophetic dream you're forcing them to read. That's even assuming your dream is prophetic in the first place. When you have a dream sequence, either you're giving your character the inexplicable powers to see the future, or you're literally writing nothing, because if it's not relevant to what we're reading next, why the hell are we reading it?
Assuming the dream is prophetic, maybe the most diehard fans of your book will go back and reread the scene, now understanding the points you were trying to make in hindsight. Maybe a few will read the book twice, picking up all the clever symbolism you spattered throughout. For the rest of us, we'll never remember what that dream sequence from twenty chapters ago had a pink hairbrush, and that stood for the fact that her life was so tangled and that she needed to straighten it out with the help of her best friend, who happened to also wear pink throughout the story. We won't remember the hairbrush. We won't remember the dream. Half of us would have read just long enough to realize it was a dream and then we would have skipped through the rest until we got to the part where the actual story starts again.
This is what I mean when I talk about reader's fatigue. It's the meaningless minutia that won't be carried over, remembered, or even read in many cases. The more of it you put into a story, the more likely you'll find people quitting your story. Unlike critic fatigue, which only hurts the quality of your critique, reader's fatigue is a phenomenon that loses you readers.
Some people take advantage of this in another mistake that a lot of new writers make, otherwise known as the introduction chapter. In an introduction chapter, people abuse the point when a person's reader's fatigue ought to be at it's lowest, when they're just starting the story, to info-dump all of the relevant information so they don't have to do it later. This is where you get long prologues detailing the entire history of this fantasy world or the girl who gets up, describes herself in a mirror, describes her parents and their jobs, goes to school, describes each of her friends and each of her classes, and only then starts her story.
However, even if you can "trick" people into reading a few chapters this way, reader's fatigue can still come into play. For many people, your book might not be the first book they've read that day. Which means when they read those same tedious chapters again and again, if it doesn't give them something new, it becomes an autoskip.
Now, I'm not saying that everyone suffers from reader's fatigue. I know there are people who force themselves to read every word of every chapter, fearful that they'll miss something important. I also know people who more skim books than actually read them, flying through the words and only picking up some of the main points. A dream that inspires one reader's imagination can become an unimaginable bore fest to the next. People are different.
Now, I must warn you, we tend to think in terms of how much someone "likes" a story, or how "good" the story is. Reader's fatigue isn't directly related to goodness or readability. For example, Shakespeare is something considered particularly good, it's also something that has a high reader's fatigue. Let's face it, how many people here would have ever read Shakespeare if it wasn't a requirement in school? There are probably a lot of "good books" that are tedious and exhausting to read. For one, I can say it took me three tries to read Lord of the Rings. I found it very dry and boring, and I think I only officially finished it because they started making the movies, and I didn't want to go into it without having finished it first.
So, don't see reader's fatigue as something bad, per say. In many cases, it's simply unavoidable. People will get tired as they read. Sometimes it's because of what you write. Sometimes it's because of how you write it. And sometimes it's because of your reader's state of mind when they read it. The best you can do is be aware of it, and take advantage of the pacing in your story to know when you can spare time for those slow fatiguing parts and when you need to pick up the pace and keep things interesting.
By keeping yourself aware of reader's fatigue, you can understand things like when it's a good time to end a chapter. After all, if a chapter just keeps going and going, people will get annoyed. They like frequent breaks. When your chapters are too long, it's like having a game with infrequent save points. It's a frustration that tires out your reader.
Being aware of reader's fatigue can also help you when you do need to write exposition. Rather than timing it in a long row, for example, you can have a nice exciting scene right before you have to spend a long time on boring stuff. For an example, let's go with the common trope of the bad boy being a former gang member and the girl being attacked by his gang. Would you rather have a scene where the girl is attacked by the gang suddenly without warning, and then after he rescues her they have a long sweet scene where he explains his backstory? Or would you rather that just after 30 pages of them making googly eyes at each other, you get another ten pages of them sitting quietly and him talking about his past... and THEN the gang shows up and attacks her? I mean, you could write it both ways. You could even call him telling her before it happens foreshadowing. However, that might also be more tedious to read. So, for most, a story where the sweet scenes come after the action/emotional/scary scenes are common.
At it's most cliche, you've probably since these achieved with prologues that show the most exciting scene first and then jump back to the boring parts. You've all seen these kinds of story starts. They all have one thing in common, the actual start of the story is slow and boring, so they desperately try to engage you so that it can blow past your reader's fatigue without having you auto-skip when you see the same boring beginning again and again.
So, like many things in the book, there isn't a step by step guide that teaches you how to lower reader fatigue. It's something you need to think about and figure out on your own. This chapter is merely here to get you thinking about your writing in a different way.These are just a couple of ways reader's fatigue ties into your story. Chapter length, pacing, word usage, story, and plot structure... all of these things come in to play when trying to make a story compelling for your readers. So, that's just one more aspect to worry about as you start compiling a story. Ummm... Good Luck?