I’ve been aware of this phenomenon since I was in junior high, or possibly even longer, but it was only in the last five years that I learned the name of it. A modifier is a word that modifies, or changes the meaning of another word. Adverbs modify verbs. Adjectives modify nouns. For example, you could use the sentence, “I ran.” That isn’t a very specific sentence, though, so you can add modifiers to make the meaning more clear. “I ran away quickly,” adds the information of where I ran (away) and how fast I was moving (quickly).
Misplaced modifiers are exactly what they sound like, a modifier in the wrong place. Most of the time, a modifier is placed directly before the word it modifies. In the sentence “I ate meat,” the word “only” can be added in three places, and give the sentence three entirely different meanings.
“Only I ate meat” would indicate that of all the persons present, I was the only one eating meat.
“I only ate meat” says that I did not prepare it, I just ate it.
“I ate only meat” says that I indulged in a meal without vegetables, fruits, or grains.
The modifier getting misplaced can sometimes be funny as well as confusing. Consider these:
“Hiking up the mountain, the thunderstorm was an unwelcome surprise to James.” Why was the thunderstorm hiking up the mountain? I can imagine it would be an unwelcome surprise to see a thunderstorm hiking up the mountain.
“Tumbling down the mountain, Susan feared the rocks would flatten her tent.” Was Susan tumbling down the mountain, or were the rocks? If Susan is falling down the side of the mountain, why is she worried about rocks smashing into her tent? I’d be more worried about me hitting the rocks on my way down the hill.
In both sentences, the problem can be solved by moving the modifying phrase closer to the word it is supposed to be modifying.
“Hiking up the mountain, James was surprised by an unwelcome thunderstorm.”
“Susan feared the rocks tumbling down the mountain would flatten her tent.”
When proofreading something you’ve written, if a sentence is awkward or doesn’t seem to make sense, try moving the modifiers around a bit, and see if the problem is a misplaced modifier.