There’s one intellectual tool that can cut through much of the bunk likely to emerge from the 2016 presidential debates. It’s not the much-discussed notion of on-the-spot fact-checking. Facts can be checked the next day. What’s needed in real time is a linguistic skill — the ability to flag innuendo, strategic gaps, subtle non sequiturs and winks and nods, and, for those privileged to act as moderators, to ask follow-up questions that force the candidates to be explicit.

Linguistics professor Andrew Kehler is an expert in indirect communication, which people deploy for both honest and shady purposes. More specifically, he studies the differences between the literal meanings of statements and the way listeners interpret them. Such a gap exists in all languages, making complex discourse possible but also enabling speakers to mislead without literally lying. “We’re always taking more information away from utterances than what is said, and we don’t realize how we are manipulated this way,” said Kehler.

He starts with a look at Donald Trump’s slogan, “Make America Great Again.” If you try to refute the statement by saying that Trump will not make America great again, you’re implying an agreement with the notion that America is no longer great, said Kehler. But the slogan never explicitly states this. Alternatively, you can argue that America is great now — which doesn’t get to the heart of the claim. To Kehler, the situation calls to mind an exchange in “Alice in Wonderland,” in which the mad hatter asks Alice if she’d like more tea, and she replies that she can’t have more because she hasn’t had any. The hatter says if she hasn’t had any, then she couldn’t have less, but could have more.

In this election cycle, you don’t need to have fallen down a rabbit hole to encounter such linguistic puzzles on a regular basis. A prime example was Trump’s now-infamous utterance regarding Hillary Clinton: “If she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people — maybe there is, I don’t know.”

If someone walked into a room and said, “Although the Second Amendment people — maybe there is, I don’t know,” you wouldn’t necessarily run for cover, said Kehler. But people tend to unconsciously impose order on language, in this case assuming a connection between the different parts of Trump’s statement. Kehler is not surprised that many people took it to imply that someone could stop Clinton from appointing liberal judges by shooting her. Trump later told a CBS affiliate that he meant gun rights advocates could vote against her. But critics then pointed out Trump seemed to be referring to the situation after she was elected, when it would be too late to vote against her.

If Trump had made the remarks in an interview or debate, rather than at a rally, someone could have asked him right away what he thought those “Second Amendment people” could do. As it was, the statement had journalists running in circles. Here’s how the fact-checking champs at PolitiFact ended a post on the matter: “Trump’s rather elliptical words certainly left room for interpretation.” Not much help there.

By contrast, it was easy for fact-checkers to flag Trump’s provably false claim that he’d been an early opponent of the Iraq War (even if his interviewers didn’t always call him out when he made it).

Given the unpopularity of fact-checking, speakers can gain an advantage from elliptical utterances. If a candidate says, for example, “I am a moral person” followed by “I oppose abortion,” most listeners would assume that the candidate thinks pro-choice folks are immoral. But this is easily denied since it wasn’t stated explicitly. A good interviewer or moderator can follow up by asking whether the candidate believes people who are pro-choice are immoral.

We all leave gaps in our speech and expect listeners to fill them in, said Kehler, and we pick up all sorts of things from other people that are not said explicitly. He calls this phenomenon the pragmatic enrichment of language. Without it “language would be almost unusable, we’d be so verbose.” But these gaps leave us open to misdirection.

A common deception technique is to answer a question with a true but irrelevant fact. That takes advantage of our urge for pragmatic enrichment. In August, I wrote about such a situation, which occurred when the founder of the troubled medical diagnostics company Theranos gave a talk at a scientific meeting. Afterward, someone asked whether there was evidence that giving healthy people more blood tests would result in better health. She answered: “There are 9 million cases of undiagnosed diabetes.” Her statement was true, but implies something that’s probably false: After the talk, experts said the company has no cheaper or better diabetes tests available or in the pipeline.

Kehler notes a similar trick that came up in a prominent perjury case, Bronston v. United States. The defendant, Samuel Bronston, was asked if he had any Swiss bank accounts. He answered that the company had one. Some people would assume this implied he did not have a personal Swiss bank account, though in fact he also did.

Advertisements use the same form of deception. If people hear that one dietary supplement has twice the iron of competitors, they might assume more iron is better. Why else would they tell you that? Kehler has many examples from the advertising world.

Political debates are a form of advertising. Candidates are there to sell themselves. Viewers should be there to question everything that’s said, and everything that’s not said as well.

Bloomberg columnist Faye Flam is a science writer and the author of “The Score: How the Quest for Sex Has Shaped the Modern Man.”

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.