In an era of information overload and sometimes intentional deception, how do we know whether what we encounter online is trustworthy or not?

Earlier this month, a Stanford expert offered advice for students, teachers and the public at large: Be like professional fact-checkers, who make an effort to discover the source of a claim as well as find competing opinions and supporting evidence.

The expert, Joel Breakstone, called the process “horizontal reading” in reference to the fact-checkers’ custom of opening multiple websites so that they can easily scan new pages for context and background on a topic and its origins.

Breakstone is director of the Stanford History Education Group, which aims to improve understanding of online information, as well as the teaching, critical thinking and understanding of historical documents.

He spoke earlier this month at Livermore’s Bankhead Theater as part of the Rae Dorough Speaker Series.

Founded in 2002, the Stanford History Education Group focused initially on preparing teachers to deal with urban schooling challenges. Its teacher education program developed new ideas for helping students learn to read historical texts and think creatively about them.

More recently, the group gained national attention when it published preliminary findings from a study of how well students interpret Internet information.

They released their results near the end of the 2016 presidential election campaign, which was drawing sharp attention to the reliability of online information because of “fake news” charges and counter charges.

The Wall Street Journal covered the Stanford study by focusing specifically on fake news, but the study was more complex, Breakstone said. The reality of news online is that there are “shades of gray” between the fake and the real.

In any case, the study and the attention given it raised the question of whether Internet readers might be gullible – might simply jump to the conclusion that whatever they read must be credible.

Trusting Google

It was not a new question. Others had found that while students know to check multiple sources of information, “in practice they simply trust what Google said,” Breakstone noted.

“Overwhelmingly” the first search result, the one at the top of the page, “was …the most credible” to the students, even though trustworthiness wasn’t the criterion for first listing.

This is an important issue for the quality of participation in a democracy, he said, because surveys have found that millennials get some 80 percent of their news online.

Stanford and others have found that from junior high on, “students struggled to make even the most basic evaluation of online information. Even college students couldn’t determine the organization behind the supposedly nonpartisan websites.”

The issue was not one of native intelligence. In fact, the opposite may be true, Stanford has shown. Its surveys included people with high intelligence, such as professional historians and freshmen at Stanford, one of the nation’s most competitive universities.

Those taken in by deceptive or misleading material typically “trust their intelligence,” Breakstone said. “They focus on the site they land on (and) read vertically, from top to bottom.

“They believe they can kind of ferret out what is a trustworthy source and what is not.”

By contrast, professional fact-checkers “distrust their intelligence.” In fact a lead fact-checker said the “greatest threat” to doing the job well is “hubris, to believe that you already know the answer to something.”

Fact-checkers are constantly being reminded to verify claims, to find supporting evidence that “actually tells us whether or not something is what it says it is,” Breakstone said.

They use the “incredible power” of the internet to link to pages that identify supporting and opposing organizations and their motives.

Breakstone said the study identified three fundamental questions that fact-checkers try to answer when evaluating online content.

First, who is behind the information? Is there a hidden organization or sponsor, and one behind that?

Second, what is the evidence? What actual facts underpin the claim that the organization is making?

Finally, are there other information sources on the topic? Do they agree or disagree with this source?

In one test, fact-checkers reading “horizontally” were more than four times faster than professional historians and five times faster than Stanford freshman at uncovering the background of MinimumWage.com, which calls itself a “nonprofit research organization dedicated to studying public policy issues surrounding employment growth.”

Fact-checkers quickly learned that MinimumWage.com is not the disinterested research organization its website claims, but a project of the Employment Policies Institute.

Employment Policies Institute, they then found, is also not neutral, but is affiliated with the Berman public relations agency, which lobbies for the restaurant industry and against increases in the minimum wage.

It took the fact-checkers an average of less than a minute to make these connections, while it took historians and Stanford freshmen 4 to 5 minutes.

The Tweet that Spread

To show how people everywhere can encounter misinformation, Breakstone cited the example of a small businessman and Trump supporter named Eric Tucker of Austin, Tex.

Following the 2016 election, Tucker noticed buses discharging passengers not far from the site of an anti-Trump protest. He took a picture and tweeted it to convey an incorrect assumption to his modest twitter following that the buses were bringing protesters to demonstrate against Trump.

As local media later determined, the buses were actually taking people to a large software conference nearby.

Tucker’s tweet was picked up by Reddit and far-right blogs like The Gateway Pundit, which added a false claim not suggested by Tucker -- that the buses and protesters had been paid for by the wealthy progressive, George Soros, in order to inflate the size of the protests.

As described later by the New York Times and the Snopes fact checking website, these sites were then picked up by Facebook and other widely read social media. President Trump then cited them scornfully as proof that the protests were rigged.

To Breakstone, the episode demonstrates the power of the Internet to modify a message, spread it far and wide and influence public perception.

“Misinformation certainly existed before. What did not exist was the ease with which that misinformation can be spread,” he said.

Tucker had not intended to mislead anyone, according to subsequent news coverage. When he realized that he had jumped to the wrong conclusion about the buses, he sent out a corrected tweet.

By then, however, the misinformation had been amplified and spread nationwide.

Breakstone pointed out that misinformation is nonpartisan, that Trump opponents have also disseminated it.

For example, he said, the claim was widely circulated online that Trump had said in a People magazine interview that if he were to run as president he would run as a Republican because Republicans are “the dumbest group of voters in the country.”

Subsequent fact-checking found no record of Trump ever making such a statement or that a photo accompanying the supposed statement had ever run in the magazine.

Honest Abe on the Internet

Breakstone quoted two past presidents, one seriously and the other facetiously, to make his point.

The serious comment was made by the fourth U.S. president, James Madison, nearly 200 years ago: “The best service that can be rendered to a country, next to that of giving it liberty, is in diffusing the mental improvement equally essential to the preservation, and the enjoyment of the blessing.”

He also posted “wise words from Abraham Lincoln” that left the audience chuckling knowingly: “Don’t believe everything you read on the Internet.”