Motivation Reaction Unit

Why is there so much hype about MRUs? Because. A well-done MRU pulls your reader further into your story. And that’s what we want, right?

Dwight says scenes are told in a series of causes and effects. Or, a series of stimuli and reactions. You string enough stimuli and reactions together, and you’ve got yourself a compelling scene.
What elements compose an MRU?
1. Motivating stimulus: the stimulus occurs outside your character

2. Character reaction: the reaction occurs inside your character
Example MRU: Hot water splashed against her skin (motivating stimulus). She yelped and sucked her finger (character reaction).

Notice, the character is NEVER the subject of the motivating stimulus. You do not want to say: She felthot water spash against her skin. Nix the “she felt”. This distances your readers. It’s a no-no.
Let’s break down the character reactionaspect of an MRU.
Three Components of Character Reaction:

1. Visceral: What emotion immediately overtakes your character? Your character has no control over this.
2. Reflex: What reflexes kicks into action? Do they duck? Gasp? Flinch? Yelp? Run? 
3. Rational Action/Speech: What does your character do or say? Your character has control over this.
Important note about order: Don’t get it wrong.
The motivating stimulus must come first. Your character can’t react to something that hasn’t happened yet. You wouldn’t want to write: She yelped and jabbed her finger in her mouth after the hot water splashed against her skin. This reads funny – the MRU is out of order.
The components of the character reaction must stay in order as well. A visceral reaction always comes before action or speech. When hot water splashes against your skin, your nerve endings burn, then you yelp. It’s not the other way around.
Get the order right and hook your reader. Get the order wrong, and your reader will know something is off, even though they might not be able to verbalize what’s wrong.
Let’s look at a detailed example:
Motivating stimulus: car backfires
Character reaction:
– Visceral reaction: pulse seizes 
– Reflex: his limbs jerk
– Action: grabs wife’s arm and spins around to locate the noise
– Speech: “What was that?”
How this would look in the story:
A loud clap splits the air (motivating stimulus).
Jack’s pulse seizes (visceral) and his limbs jerk (reflex). He grabs his wife’s arm and spins in all four directions, trying to locate the source of the noise. (action) “What was that?” (speech)
Notice: I showed the visceral response. I didn’t tell it. I didn’t write – Jack is startled. Also, the stimulus and the reaction have their own separate paragraphs. This should always be the case.
Should we put all four elements of character reaction in every MRU?
Of course not! Unless you want to exhaust your reader.

So how do you know when to put all the elements in?
-When you want to increase tension
-When you want to highlight something important
When you want to highlight something important and increase tension, this is prime time to bring your reader deep and include every component of the MRU.
Questions to Ponder: How do you feel about MRUs? Did this help you understand them better? Any questions you still have about them? I can try to explain if you do.


25 thoughts on “Motivation Reaction Unit

  1. Pat

    Ugh. It’s really easy to put MRUs in a contrived example like hot water splashing on a character’s skin. Anyone can do it. But impossible in a long chain of writing when you’re building character thoughts and plot lines.

  2. David

    I have been studying The Marshall Plan for Novel Writing and must admit got confused because “Sections” (He says they are not Scenes)includes the same format for the overall larger construction.
    MRU’s your using are applied to only the conflict part of his construction and what a gem this explanation is! Thank You

  3. […] Dwight says only four things are needed to write a solid story: 1. How to group words into motivation-reaction units (MRUs) 2. How to group MRUs into scenes and sequels 3. How to group scenes and sequels into story patterns […]

  4. Katie Ganshert

    Hey Anon – great question! I think the answer is just what you said. Not every line is going to be an MRU. You'll have description and other things. But knowing the concept of MRU and when to use it will help our writing come alive and draw the reader deeper into the story.

  5. Anonymous

    where does motivation-reaction leave room for things like description where there's not always a reaction or with things like "Johnny got up." if it's not reaction or motivation for anything, what is it? this is something Dwight swain didn't cover in his book. thanks

  6. patti.mallett_pp

    Don't recall ever hearing about MRU's. Obviously, I'm a novice and looking for all the help I can find. So glad to have discovered you and this very helpful blog! Thanks!

  7. Karin Zirk

    When ever I'm trying to "fix" a scene, I drop down to the MRU level and it usually helps me identify when I have two many reactions, when I'm missing any reaction, or when the reactions are out of order. Once I fix my MRU, the scene usually flows much better.

  8. Katie Ganshert

    I'm glad the post was helpful! Thanks for your comments. I truly enjoy reading them. 🙂

  9. Kate Karyus Quinn

    Hi, I just came across your blog through… hmmm… I can't remember now, but just wanted to say this is a great post! I have never heard the term MRU before, but everything you've written about here makes great sense to me!

  10. sherrinda

    Don't laugh, but I've never heard of MRU's before. Seriously. How pathetic is that? But you explained it well!!! 🙂

  11. Jordan McCollum

    I'm so glad you're doing this series! I was unimpressed by Swain's book, although I'd heard such wonderful things about it. (Didn't help that I'd just read two books developing some of his concepts into full craft books.) I'm excited to get to the meat!

  12. Erica Vetsch

    Great examples! MRUs were something I struggled with understanding for awhile.

  13. Jody Hedlund

    I'm getting out a notecard to write down your summary! It's a great one to keep with my stack of writing notes that I always need to review!

  14. Jill Kemerer

    I can't tell you how many times I used to write it backwards in my rough drafts! Thanks for the recap. I can always use the reminder.

  15. Katie Ganshert

    You're welcome Elana! Thanks for visiting Brain Throw Up. I hope you come back. 🙂

  16. Katie Ganshert

    I couldn't agree more, Eileen. I struggle the most with viceral. Mainly because I think that's when cliche comes creeeping in. Seriously, how many ways are there to say somebody's heart pounded?

    Yay, Jessica! I'm glad this post helped expalin them better. My goal was to lay them out as basic and as simple as I could.

    Thanks Elizabeth! I appreciate the tweets!

    Best of luck, Heather. Let me know how it goes.

    Galen and Bonnie. Memory Resident Unit. Meals Ready to Upchuck. Those are halarious. Made me laugh out loud. 🙂

    I hear ya, Wendy. I thought the same thing as I read Dwight's book. I was thinking most of us probably write this way without noticing. BUT, just like you said, I've never thought about manipulating the MRU to enhance tension. This was probably the most valuable piece of advice I got from Dwight regarding MRUs.

    Aw, Ralene, thanks! I'm glad the post brought clarity and I'm honored you love my blog. 🙂

  17. ElanaJ

    Wow, this is fantastic! And I've never heard this term MRU before, but it's so true! This is a great great post. Thanks for sharing!

  18. Ralene

    Thank you, Katie. I'be been looking for a good summary of MRUs. This really helped to clarify for me. Did I ever tell you how much I love your blog? 🙂

  19. Wendy @ All in a Day's Thought

    Insightful. As I read this I was thinking I imagine most of us write this way naturally, but as I thought more about it, I concluded I bet there are times we throw all four into the novel when only two are needed and write two when four would build more tension.

    I'm thinking….
    ~ Wendy

  20. Bonnie Doran

    Thanks for the post. I finally understand a smidgeon about MRUs, which are not Meals Ready to Upchuck!

  21. Galen Kindley--Author

    I'm, of course, with the uninitiated. Had I been told to monitor my MRUs, I woulda been looking for the Memory Resident Unit on my computer. So, it’s a good lesson that’s well learned. (Sounds like Poor Richard’s…but, it’s me). Thank you for getting me up to speed. Guess this means I have one more thing to proof for. Sigh.

    Best regards, Galen

    Imagineering Fiction Blog

  22. Heather Sunseri

    Great post, Katie. I think I'll work on MRU's today.

  23. Elizabeth Spann Craig

    Very interesting. I've never thought about it that way. Okay, I'm tweeting this one, too. 🙂

    Mystery Writing is Murder

  24. Jessica

    This absolutely helped me understand them better. I had a contest entry in which the judge kept telling me to study MRUs. It made me grit my teeth at the time because I've heard of them but trying to figure it out is like doing math for me. It makes my brain short. But this helped a lot and now I think I understand them better. Thanks Katie!

  25. Eileen Astels Watson

    This is a great summary! I'm always stopping myself during writing to put myself in the character's postition to figure out the visceral reaction. It's the hardest for me. It had happens so involuntarily and fast that we don't really take note of it in real life. But it's definitely there. If I'm going to forget one of reactions, it's the visceral every time. Which isn't always bad.


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