Ed Skrein and Michael Huisman as Game of Thrones' Daario Naharis. (Photo: HBO)

There's a moment at the beginning of the fourth season of HBO’s Game of Thrones that's particularly jarring—and it has nothing to do with beheadings or incest. Between seasons, the character of Daario Naharis—the long-haired sword-wielder who serves as Daenerys Targaryen's enforcer/advisor/lover—got a drastic makeover; showrunners David Benioff and Dan Weiss replaced actor Ed Skrein with Michael Huisman.

Whatever the reason—reportedly, because Skrein needed time to star in a new Transporter movie—this kind of acting change, whether on television or in a movie franchise, is rare, but not unheard of. It occurs for any number of reasons—contractual disputes, scheduling conflicts, artistic differences, even death. (Michael Gambon played Dumbledore in the last six Harry Potter movies after the original actor, Richard Harris, passed away.) And every time it happens, it feels super weird. We know it’s make-believe, but we feel slighted, confused, irritated.

What's happening to our brains during these moments of dissonance? Why are we so thrown when our favorite fictional characters are suddenly inhabited by different people?

There’s no neat answer, but to find ourselves close to one, we have to go way back to the birth of fiction—which is a contested issue. Some feel it originated with the earliest cave paintings, dated to 35,000 B.C.E., while others, partial to the written word, think that 2100 B.C.E.’s Mesopotamian poem "Epic of Gilgamesh" is the first piece of fiction. The point being: Our capacity to construct fiction became possible when we developed the ability to communicate.

“[With language] humans were able to separate the present from the past and the future, and when that happens, the idea of a story follows pretty quickly,” Daniel McDonald, a professor of communication at the Ohio State University, writes in an email. The linguistic concept of tenses allowed humans to describe what happened in the past, and also what could happen in the future. What, after all, is the entire future tense other than a kind of fictional story?

Why are we so thrown when our favorite fictional characters are suddenly inhabited by different people?

Since then, the modes of storytelling and our critical shrewdness have increased, but the magic of fiction remains. In 1817, the philosopher and poet Samuel Taylor Coleridge coined the term “suspension of disbelief” to describe an audience's ability to still appreciate a work of fiction despite its narrative implausibility. We don't need to believe Han Solo and Chewbacca are actually traveling at the speed of light to enjoy the story, for example. But what does matter—what viewers are unlikely to look past—is consistency, or lack thereof.

Sound, continuity, editing, mood—successful filmmaking largely depends on the consistency from one shot to the next, one scene to the next. Anything too jarring forces viewers into the "I'm watching a movie right now" mindset, potentially ruining the magic.

We are all, to some degree, playing critics while watching movies. “There’s evidence accumulating that suggests our brains oscillate back and forth between the world of the fictional character, in which we track events as if it were a real world, and an introspective, detached appraisal of the story,” McDonald writes. That is, not only are we viewing the contents of the story, but we're viewing—and, thusly, judging—the story as a story. “Some researchers think it’s actually the switching between these two different modes of thinking that gives us much of the enjoyment we receive from entertainment.”

When an actor's replaced, our brain spends an excessive amount of time in this critical portion of the experience. In the example of switching Game of Thrones actors, then, it's not necessarily whether or not one actor is better than the other, as much as whether or not the latter is consistent with the original interpretation. One big thing possibly giving Thrones viewers an issue is the fact that Season 3 Daario is clean-shaven and long-haired, while Season 4 Darrio is neither. “That inconsistency would cause a disruption, and call for greater scrutiny of the production aspect, interrupting some of the enjoyment of the narrative,” McDonald writes.

Want to see how much disruption these types of casting changes cause? Go ahead and Google “Bond actor ranking” and duck.

When casting agents are looking for a new actor to fill an existing role, however, the thought process is a little different: They have a loyalty to what's on the page, the character, and that means consistency be damned if they find a better match.

“For me, personally, the most important thing is choosing the actor who embodies the character the writer intended,” says Stephanie Fredricks, a casting director and actress. “That often includes look and voice, but it's not about matching the previous actor in either. You stay as true to the character as possible, or you lose your audience.”

This makes sense for a few reasons, the most obvious being that if you're replacing an actor, something obviously wasn't working. (In Thrones, a big rumor regarding the original Daario was that he didn't have the desired macho sex appeal required for Season 4.) Not being happy with Actor A and subbing them out with an act-a-like is like saying, “I hate burgers, let's go get a steak.”

But Fredricks knows that, no matter how carefully she weighs the decision, only a portion of the audience buys in. “You're always going to piss someone off when you re-cast their favorite actor,” she says. “You can never make everyone happy. You just hope that, over time, they think less about the new actor, and more about the character they're playing.”

When I posed the question about this dissonance to Keith Oatley, a professor emeritus of cognitive psychology at the University of Toronto, and author of the 2011 book Such Stuff as Dreams: The Psychology of Fiction, he theorized that it may come from “parasocial relationships,” wherein the audience builds relationships—quite intense ones, sometimes—with fictional characters.

We're seeing and hearing these fictional characters on a pretty consistent basis, maybe more often than certain loved ones.

“Some parasocial relationships can be considered complementary to everyday relationships,” Oatley writes in an email. “In contrast, romantic relationships of the parasocial kind, for the most part with opposite-sex celebrities, were often of the compensatory kind: Single people reported greater imagined intimacy with parasocial partners than did those who were in a relationship.”

In the 1950s, researchers Donald Horton and Richard Wohl examined extreme parasocial interaction by, in part, looking at the popular radio serial the Lonesome Gal. The only character was a woman with no name or history. Each night, according to Horton and Wohl, she delivered a monologue in a “throaty, unctuous voice,” the eroticism of which “belied the seeming modesty of her words.” It wasn’t long until the radio station's mailbox was full of marriage proposals, according to Oatley.

Why do these relationships occur? Oatley cited research by SUNY psychologist Gayle Stever, who interviewed those with parasocial relationships. One woman, who'd been the near victim of date rape, said she preferred the safety of relationships with people she'd never met. Another, who's husband died, said that her feelings toward a celebrity “made her realize she could still be attracted to men, and enabled her to get back in touch with her feelings.”

But those are extreme cases. For the rest of us, it's just about cultivating relationships. In the case of a television show or film franchise, we're seeing and hearing these fictional characters on a pretty consistent basis, maybe more often than certain loved ones. And we're right there with them, “living” through their most dramatic experiences. It's a type of Turing Test, but rather than artificial intelligence, the actors and producers are trying to convince us that our favorite fictional characters are real.

That weirdness we feel when an actor's been replaced, then, is a jolting wake-up call that the people, the events, and the fictions we've accidentally built relationships with don't even exist. And that could be even more traumatic than watching a character getting their head chopped off.

The Sociological Imagination is a regular Pacific Standard column exploring the bizarre side of the everyday encounters and behaviors that society rarely questions.