Of all the writing errors you can make, misplaced modifiers are among the most likely to confuse your readers, but they're also kind of fun because misplaced modifiers can give your sentences silly meanings that you never intended. If you're not careful, you can end up writing that your boss is a corn muffin instead of that your boss invested in corn muffins.
I once worked with an editor who e-mailed everyone in the office the especially hilarious sentences created by misplaced modifiers. Each day, we produced enough reports to keep two copy editors busy, and many of the writers were scientists, so there were always lots of opportunities to find misplaced modifiers. The e-mails were entertaining, unless you were the one who had written the offending sentence.
What Are Modifiers?
Modifiers are just what they sound like—words or phrases that modify something else. Misplaced modifiers are modifiers that modify something you didn't intend them to modify. For example, the word only is a modifier that's easy to misplace.
These two sentences mean different things:
I ate only vegetables.
I only ate vegetables.
The first sentence (I ate only vegetables) means that I ate nothing but vegetables—no fruit, no meat, just vegetables.
The second sentence (I only ate vegetables) means that all I did with vegetables was eat them. I didn't plant, harvest, wash, or cook them. I only ate them.
It's easiest to get modifiers right when you keep them as close as possible to the thing they are modifying. When you're working with one-word modifiers, for example, they usually go right before the word they modify.
Here's another example of two sentences with very different meanings:
I almost failed every art class I took.
I failed almost every art class I took.
The first sentence (I almost failed every art class I took) means that although it was close, I passed all those classes.
The second sentence (I failed almost every art class I took) means that I passed only a few art classes.
Note again that the modifier, almost, acts on what directly follows it—almost failed versus almost every class. In either case, I'm probably not going to make a living as a painter, but these two sentences mean different things.
How to Use Commas with Modifiers
A similar rule applies when you have a short phrase at the beginning of a sentence: whatever the phrase refers to should immediately follow the comma. Here's an example:
Rolling down the hill, Squiggly was frightened that the rocks would land on the campsite.
In that sentence, it's Squiggly, not the rocks, rolling down the hill because the word Squiggly is what comes immediately after the modifying phrase, rolling down the hill.
To fix that sentence, I could write, “Rolling down the hill, the rocks threatened the campsite and frightened Squiggly.” Or I could write, “Squiggly was frightened that the rocks, which were rolling down the hill, would land on the campsite.”
Here's another funny sentence:
Covered in wildflowers, Aardvark pondered the hillside's beauty.
In that sentence, Aardvark—not the hillside—is covered with wildflowers because the word Aardvark is what comes directly after the modifying phrase, covered in wildflowers.
If I want Aardvark to ponder a wildflower-covered hillside, I need to write something like, “Covered in wildflowers, the hillside struck Aardvark with its beauty.”
Here, the words the hillside immediately follow the modifying phrase, covered in wildflowers.
Or better yet, I could write, “Aardvark pondered the beauty of the wildflowers that covered the hillside.”
I can think of more ways to write that, but the point is to be careful with introductory statements: they're often a breeding ground for misplaced modifiers, so make sure they are modifying what you intend.
Dangling and Squinting Modifiers
Modifiers are so funny! In addition to misplacing them, you can dangle them and make them squint!
A dangling modifier describes something that isn't even in your sentence. Usually you are implying the subject and taking for granted that your reader will know what you mean—not a good strategy. Here's an example:
Hiking the trail, the birds chirped loudly.
The way the sentence is written, the birds are hiking the trail because they are the only subject present in the sentence. If that's not what you mean, you need to rewrite the sentence to something like, “Hiking the trail, Squiggly and Aardvark heard birds chirping loudly.”
And how do you make a modifier squint? By placing it between two things that it could reasonably modify, meaning the reader has no idea which one to choose.
Children who laugh rarely are shy.
As written, that sentence could mean two different things: children who rarely laugh are shy, or children who laugh are rarely shy.
In the original sentence (Children who laugh rarely are shy) the word rarely is squinting between the words laugh and are shy. I think “shifty modifier” would be a better name, but I don't get to name these things, so they are called squinting modifiers (or sometimes they are also called two-way modifiers).
So remember to be careful with modifying words and phrases—they are easily misplaced, dangled, and made to squint. My theory is that these problems arise because you know what you mean to say, so the humor of the errors doesn't jump out at you. Misplaced modifiers often crop up in first drafts and are often easily noticed and remedied when you re-read your work the next day.