Mueller Finds No Trump-Russia Conspiracy”, read the front page headline of Sunday’s New York Times. Bit by bit, mainstream American consciousness is slowly coming to terms with the death of the thrilling conspiracy theory that the highest levels of the US government had been infiltrated by the Kremlin, and with the stark reality that the mass media and the Democratic Party spent the last two and-a-half years monopolizing public attention with a narrative which never had any underlying truth to it.

There are still holdouts, of course. Many people invested a tremendous amount of hope, credibility, and egoic currency in the belief that Robert Mueller was going to arrest high-ranking Trump administration officials and members of Trump’s own family, leading seedy characters to “flip” on the president in their own self-interest and thereby providing evidence that will lead to impeachment. Some insist that Attorney General William Barr is holding back key elements of the Mueller report, a claim which is premised on the absurd belief that Mueller would allow Barr to lie about the results of the investigation without speaking up publicly. Others are still holding out hope that other investigations by other legal authorities will turn up some Russian shenanigans that Mueller could not, ignoring Mueller’s sweeping subpoena powers and unrivaled investigative authority. But they’re coming around.

The question still remains, though: what the hell happened? How did a fact-free conspiracy theory come to gain so much traction among mainstream Americans? How were millions of people persuaded to invest hope in a narrative that anyone objectively analyzing the facts knew to be completely false?

The answer is that they were told that the Russiagate narrative was legitimate over and over again by politicians and mass media pundits, and, because of a peculiar phenomenon in the nature of human cognition, this repetition made it seem true.

The rather uncreatively-named illusory truth effect describes the way people are more likely to believe something is true after hearing it said many times. This is due to the fact that the familiar feeling we experience when hearing something we’ve heard before feels very similar to our experience of knowing that something is true. When we hear a familiar idea, its familiarity provides us with something called cognitive ease, which is the relaxed, unlabored state we experience when our minds aren’t working hard at something. We also experience cognitive ease when we are presented with a statement that we know to be true.

We have a tendency to select for cognitive ease, which is why confirmation bias is a thing; believing ideas which don’t cause cognitive strain or dissonance gives us more cognitive ease than doing otherwise. Our evolutionary ancestors adapted to seek out cognitive ease so that they could put their attention into making quick decisions essential for survival, rather than painstakingly mulling over whether everything we believe is as true as we think it is. This was great for not getting eaten by saber-toothed tigers in prehistoric times, but it’s not very helpful when navigating the twists and turns of a cognitively complex modern world. It’s also not helpful when you’re trying to cultivate truthful beliefs while surrounded by screens that are repeating the same bogus talking points over and over again.

I’m dealing with a perfect example of the perils of cognitive ease right now. Writing this essay has required me to move outside my familiar comfort zone of political commentary and read a bunch of studies and essays, think hard about new ideas, and then figure out how to convey them as clearly and concisely as possible without boring my audience. This movement away from cognitive ease has resulted in my checking Twitter a lot more often than I usually do, and seeking so much distraction that this essay will probably end up getting published about twelve hours later than I had intended. Having to read a bunch of scholars explaining the precise reasons why I’m acting like such an airhead hasn’t exactly helped my sense of cognitive ease any, either.

SNIP