Matt Lauer’s failure to fact check Donald Trump's most brazen lies at NBC's Commander-in-Chief Forum has intensified discussion about what should be expected of presidential debate moderators. Experts say that correcting lies and fabrications like Trump's requires very specific techniques.

In a piece crediting the New York Times for (finally) forcefully challenging Trump on (one of) his most recent lies, Peter Beinart prescribes the following:

[Debate moderators]—Lester Holt, Martha Raddatz, Anderson Cooper and Chris Wallace—must be prepared to confront Trump in ways they’ve never confronted a candidate before. The more audaciously he lies, the more audaciously they must tell the truth.

Beinart is correct. Debate moderators must tell the truth audaciously. Social science teaches us that basic corrections are not enough. In fact, without greater context, they can make matters worse.

From Misinformation and Fact-checking: Research Findings from Social Science, by academic experts Brendan Nyhan and Jason Riefler:

Attempts to correct false claims can backfire via two related mechanisms. First, repeating a false claim with a negation (e.g., “John is not a criminal”) leads people to more easily remember the core of the sentence (“John is a criminal”). Second, people may use the familiarity of a claim as a heuristic for its accuracy. If the correction makes a claim seem more familiar, the claim may be more likely to be seen as true.

With Trump, due to the incessancy of his lies, the danger of reinforcing misinformation is especially great. So what would it look like, in the face of those lies, to actually correct the misperceptions they create?

The Debunking Handbook, by Australian academic experts John Cook and Stephan Lewandowsky, is instructive:

To avoid these “backfire effects”, an effective debunking requires three major elements. First, the refutation must focus on core facts rather than the myth to avoid the misinformation becoming more familiar. Second, any mention of a myth should be preceded by explicit warnings to notify the reader that the upcoming information is false. Finally, the refutation should include an alternative explanation that accounts for important qualities in the original misinformation.

Moderators won’t be able to anticipate every lie Trump conjures. But by now, his lying has become so predictable, there’s no reason they can’t be well prepared for almost all of it.

Will there be push back from Trump, his campaign, right-wing media, and the mainstream reporters they are able to influence? Absolutely. As Beinart noted, “The risks of doing so are tremendous,” yet:

The rewards are being able to say that when Donald Trump threatened American liberal democracy like no candidate in modern history, you met his challenge square on.

Trump has thrown out the playbook. Moderators must meet his challenge.

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