Sitting in front of a computer not long ago, a tenured history professor faced a challenge that billions of us do every day: deciding whether to believe something on the Internet.

On his screen was an article published by a group called the American College of Pediatricians that discussed how to handle bullying in schools. Among the advice it offered: schools shouldn’t highlight particular groups targeted by bullying because doing so might call attention to “temporarily confused adolescents.”

Scanning the site, the professor took note of the “.org” web address and a list of academic-looking citations. The site’s sober design, devoid of flashy, autoplaying videos, lent it credibility, he thought. After five minutes, he had found little reason to doubt the article. “I’m clearly looking at an official site,” he said.

What the professor never realized as he focused on the page’s superficial features is that the group in question is a socially conservative splinter faction that broke in 2002 from the mainstream American Academy of Pediatrics over the issue of adoption by same-sex couples. It has been accused of promoting antigay policies, and the Southern Poverty Law Center designates it as a hate group.

Trust was the issue at hand. The bookish professor had been asked to assess the article as part of an experiment run by Stanford University psychologist Sam Wineburg. His team, known as the Stanford History Education Group, has given scores of subjects such tasks in hopes of answering two of the most vexing questions of the Internet age: Why are even the smartest among us so bad at making judgments about what to trust on the web? And how can we get better?

Wineburg’s team has found that Americans of all ages, from digitally savvy tweens to high-IQ academics, fail to ask important questions about content they encounter on a browser, adding to research on our online gullibility. Other studies have shown that people retweet links without clicking on them and rely too much on search engines. A 2016 Pew poll found that nearly a quarter of Americans said they had shared a made-up news story. In his experiments, MIT cognitive scientist David Rand has found that, on average, people are inclined to believe false news at least 20% of the time. “We are all driving cars, but none of us have licenses,” Wineburg says of consuming information online.