We live in the modern world (well, duh). A lot of the writing we do is set in a modern-day setting. Yet when writing fiction, or historical nonfiction, there are many times when you might be writing about a setting that has a great many differences from what you know and are familiar with. In order to keep such writing believable, it’s important to avoid clashing with language that is ‘too modern.’ That doesn’t mean Ye Must Speaketh Inne Ye Olde Tongue, but it does mean that sometimes, depending on your setting and genre, it’s important to avoid using too many modern references.
There’s two main areas where I tend to see this sort of mistake made. The first is in anything set in the past, which in a fantasy setting is most commonly a medieval or renaissance period. Obviously it’s important to be historically accurate (such as, for example, knowing when gunpowder was invented before deciding whether or not to include it in your work). But I’m not here to discuss historical accuracy. Rather, I’m referring to modern references that can jar the reader out of the work.
A simple example would be something like referring to a character’s chaotic life as something like “a never-ending roller coaster ride.” Obviously, if the setting of the story is before the invention of roller coasters, then such a modern invention shouldn’t be referenced at all– even in the narrative text. This can not only make the phrase seem out of place, but it can result in a shift in perspective (from 3rd person limited to 3rd person omniscient). In most stories, unless you’re choosing an omniscient perspective, it’s important only to refer to things that the character knows and understands. Accidental point-of-view-shifts tend to be most common with things like having one character reference another’s thoughts or emotions, since those are things the character you’re narrating wouldn’t ‘know’ (unless they’re some sort of psychic, which is common enough in fantasy writing). But it can also still break the point of view when the narrative text refers to things that could only exist outside the story’s setting.
This also applies to pop culture references. You don’t want to refer to a bear as reminiscent of Winnie the Pooh in a story that is set centuries before Ol’ Pooh Bear was ever invented.
In addition to historical fiction, the second area I see this mistake in is alternate worlds. It is common in both fantasy and science fiction for the setting to be a completely made-up world that has a different history and culture than Earth. My novel, “Manifestation,” is an example of that. Since I set it in an alternate world, I had to be very careful not to reference any real-world politics, celebrities, or pop culture. A simple example of that would be Dr. Caldwell’s cat: I briefly considered having her name it “Sigmund” or “Jung” after a famous psychiatrist, before catching myself and remembering those psychiatrists wouldn’t exist in my fictional world.
(The fact that the cat remains unnamed in the first draft is no small coincidence).
Of course, there’s another whole problem with using pop culture references in any work: they become dated and cliched. Readers today might recognize a reference to, say, Snookie or Honey Boo Boo, but they are likely to fade from memory in ten or twenty years. You’ll lose the reader if they get confused about a reference they don’t understand or aren’t familiar with. That doesn’t mean they can’t be used; the intertextuality of drawing on the reader’s previous knowledge and experiences can be helpful in making your writing tighter and cleaner. For example, it’s far easier for me to just say, “He had hair like a Muppet,” without having to go into deeper detail by clarifying, “He had hair like a Muppet: wild, unruly, and childishly carefree.” Most readers (presumably) will get the image just fine without having it explained to them (which also brings us into the territory of “Show, Don’t Tell”). The important thing is to understand your target audience, and make sure the reference won’t be lost on them, or else you’re leaving them confused and breaking them out of the story.
Though on the other hand, you might just introduce a reader to a new word, phrase, or reference and teach them something. Which just goes to show that, like with any and all writing tips, it’s always a question of what works best for your story.