There’s a problem with the media’s repetitive refutation of Donald Trump’s lies: It makes them more credible. Research finds that repeating a lie, even to refute it, imprints it on our brains, and they become more memorable than the refutations.

Most presidents lie. Nixon said he was not a crook. Reagan said he wasn’t aware of the Iran-Contra deal. Clinton said he did not have sex with that woman.

But Trump’s lies are different. They are more frequent and glaringly contradict the facts: Obama wiretapped the phones at Trump Tower; there was record turnout at Trump’s inauguration; Trump knows no one who has anything to do with Russia; he knows more about ISIS than our generals.

How many times and from how many different newscasters and experts have we heard about these lies? Even in the face of constant references to their falsity, they are still there, imprinted on our brains.

Why do such lies persist in our memories, while repeated proof of their falsity fades; and why do we still believe the lie, or not change our opinions of the liar? Two theories can explain this.

One theory is called “confirmation bias.” It describes the tendency to search for or interpret information in a way that confirms one's preconceptions.” Some psychologists describe it as the “prevalence of directional reasoning that aims not at truth, but at the vindication of prior opinions.” Even the most well-educated and smartest among us succumb to this phenomenon.

Psychological studies find that to conclude that a statement is a lie, our brain must first record the statement for an instant as true. We must accept something to understand it. Only then, can we engage it to process the refutation. However, the imprint of the statement endures, while the refutation fades in our memory. Also lucky for Trump, is that our brains are particularly ill-equipped to deal with lies when they come not singly but in a constant stream.

These phenomena are alive and well among Republicans. Eighty-six percent of them continue to support Trump despite the media’s repeated debunking of his obvious lies.

Joseph Goebbels wrote, “If you tell a lie big enough and keep repeating it, people will eventually come to believe it … The lie can be maintained only for such time as the State can shield the people from the … consequences of the lie.” Hitler coined the expression “the Big Lie” in Mein Kampf. He wrote of a lie so "colossal" that no one would believe anyone "could have the impudence to distort the truth so infamously."

Trump seems to understand this. According to his ex-wife, Ivana, he kept My New Order, a book of Hitler's collected speeches, near his bed and read it from time to time. Trump himself said in The Art of the Deal, “Tell people a lie 3 times, they will believe anything.” He clearly knows that colossal lies attract colossal press coverage, and that it works for him even when the press refutes them.

As Goebbels said, “The lie can be maintained only for such time as the State can shield the people from [its] … consequences.” To be sure, there are consequences.

I have participated in rating the sovereign debt of several countries. I doubt that Trump’s behavior by itself will lower S&P’s double A+ and Moody’s and Fitch’s triple A ratings of U.S. debt (as it might in other countries). But Moody’s and Fitch already have their U.S. ratings on negative outlook, and given continued fiscal deterioration or continued political brinksmanship, which can be caused by the poor governance we’re witnessing in the Trump administration, downgrades are possible.

Another consequence: Media coverage has made the world aware of Trump’s lies and his responses with incessant tweeting and vicious attacks on the press and other critics. As a result, our allies and trading partners are uncertain and worried about our trade, economic and military relations with them, which has frozen progress in those areas.

We know the media, particularly broadcast media, must be conscious of their ratings. But their fundamental mission is to inform and not distort information by excessive coverage in pursuit of higher ratings. It’s a thorny problem for journalists to know when coverage distorts. Perhaps they should report the lies enough to debunk them through evidence and experts, and be reasonably confident that their reporting has been heard.