In his new book, “Fall,” the celebrated sci-fi author Neal Stephenson envisions a future United States split between the violent, gun-toting, uneducated, cross-burning religious fanatics of bullet-ridden “Ameristan” and the peaceful, educated, secular denizens of the nation’s Blue enclaves, where decorum and truth always prevail.

Stephenson, one of the most imaginative novelists of our time, fails to live up to his usual standards with “Fall.” Cultural and political elites have long depicted a Red America teeming with slack-jawed extremists; there is nothing original about his vision. In fact, it isn’t very far ­removed from the perception many coastal elites hold today.

A widely quoted new study, “The Perception Gap,” finds that both Democrats and Republicans imagine that almost twice as many people on the other side hold radical views than actually do. The study is the work of a group called More in Common. Yet even some of its polling questions reproduce the same biases the group decries, framing liberal positions as natural or mainstream and conservative ones as extreme.

Be that as it may, it’s true that news bubbles and social media feeds — which Stephenson envisions will evolve into individualized streams that create millions more unenlightened conspiracy theorists in the future — continue to insulate Americans from constructive debate and understanding. Even so, “The Perception Gap” offers plenty of clues that illustrate how it’s progressives who are creating an irreparable schism in political life.

In Stephenson’s “Fall,” the more educated a person becomes, the better he is at comprehending his compatriots. But according to the “The Perception Gap,” this is a fiction.

While the misperceptions that Republicans harbor about Democrats don’t improve with higher levels of education, the misconceptions Democrats have regarding Republicans only get worse with every additional degree they earn.

“This effect is so strong,” the study’s authors note, “that Democrats without a high-school ­diploma are three times more accurate than those with a postgraduate degree.”

This trend is less surprising when we learn that the more educated Democrats are, the less likely they are to be friendly with anyone who doesn’t share their worldview. Those with a postgraduate degree, in fact, are 50% more likely to say that “almost all” of their friends share their views than Americans with only a high school diploma.

There’s nothing inherently wrong with associating with people who see the world as they do — we have plenty of room in the United States, after all. The problem is that, despite their close-mindedness, these elites are the ones who become the technocrats who write our policies, the politicians who govern us, the teachers who claim to educate us and the activists who attempt to coerce us to adopt their values.

It is the educated elite, people clustered in centers and industries of power — not the populist voters scattered across the country — who are driving our polarization.

It isn’t merely about a disparity in perception, as the study notes, but a fundamental ignorance about the religious and philosophical viewpoints of social conservatives and working-class Americans. This condescension is palpable in the often-oblivious media coverage of Red America, which oscillates in tone from zoological study to outright mockery.

According to “The Perception Gap,” Democrats are slightly more inclined than Republicans to see their countrymen as brainwashed, hateful and racist. My own experience, as a Blue State native who’s spent plenty of time in Red America, is that liberal disdain for the American heartland is unmatched.

Whether or not you agree with all their favored policy — and I certainly don’t — the populist movements now flourishing around the world are an organic reaction to the arrogance of this ruling class.

In some ways, of course, the political world is a mirage. The constant ideological combat on social media isn’t how most Americans experience daily life in their country. Few sane people go about their daily business wondering if the person next to them at a Target is a devout Christian or progressive.

We shouldn’t exaggerate our differences. Still, as one of the knuckle-draggers — which is to say, a person who is highly skeptical of social science in general — I find it improbable that both sides are equally responsible for the ­increasing polarization of America.

Twitter: @DavidHarsanyi