That doesn’t mean all interpretations are accepted as valid. When the son of a Holocaust survivor came to her class, Erin McCarthy told her students that some people denied the existence of the Holocaust, and taught them to examine the evidence and reject those false claims. This is part of a broader movement to teach kids to think like fact-checkers: the guidelines include (1) “interrogate information instead of simply consuming it,” (2) “reject rank and popularity as a proxy for reliability,” and (3) “understand that the sender of information is often not its source.”

These principles are valuable beyond the classroom. At our family dinner table, we sometimes hold myth-busting discussions. My wife and I have shared how we learned in school that Pluto was a planet (not true anymore) and Columbus discovered America (never true). Our kids have taught us that King Tut probably didn’t die in a chariot accident and gleefully explained that when sloths do their version of a fart, the gas comes not from their behinds but from their mouths.

Rethinking needs to become a regular habit. Unfortunately, traditional methods of education don’t always allow students to form that habit.

THE DUMBSTRUCK EFFECT

It’s week twelve of physics class, and you get to attend a couple of sessions with a new, highly rated instructor to learn about static equilibrium and fluids. The first session is on statics; it’s a lecture. The second is on fluids, and it’s an active-learning session. One of your roommates has a different, equally popular instructor who does the opposite—using active learning for statics and lecturing on fluids.

In both cases the content and the handouts are identical; the only difference is the delivery method. During the lecture the instructor presents slides, gives explanations, does demonstrations, and solves sample problems, and you take notes on the handouts. In the active-learning session, instead of doing the example problems himself, the instructor sends the class off to figure them out in small groups, wandering around to ask questions and offer tips before walking the class through the solution. At the end, you fill out a survey.

In this experiment the topic doesn’t matter: the teaching method is what shapes your experience. I expected active learning to win the day, but the data suggest that you and your roommate will both enjoy the subject more when it’s delivered by lecture. You’ll also rate the instructor who lectures as more effective—and you’ll be more likely to say you wish all your physics courses were taught that way.

Upon reflection, the appeal of dynamic lectures shouldn’t be surprising. For generations, people have admired the rhetorical eloquence of poets like Maya Angelou, politicians like John F. Kennedy Jr. and Ronald Reagan, preachers like Martin Luther King Jr., and teachers like Richard Feynman. Today we live in a golden age of spellbinding speaking, where great orators engage and educate from platforms with unprecedented reach. Creatives used to share their methods in small communities; now they can accumulate enough YouTube and Instagram subscribers to populate a small country. Pastors once gave sermons to hundreds at church; now they can reach hundreds of thousands over the internet in megachurches. Professors used to teach small enough classes that they could spend individual time with each student; now their lessons can be broadcast to millions through online courses.

It’s clear that these lectures are entertaining and informative. The question is whether they’re the ideal method of teaching. In the physics experiment, the students took tests to gauge how much they had learned about statics and fluids. Despite enjoying the lectures more, they actually gained more knowledge and skill from the active-learning session. It required more mental effort, which made it less fun but led to deeper understanding.

For a long time, I believed that we learn more when we’re having fun. This research convinced me I was wrong. It also reminded me of my favorite physics teacher, who got stellar reviews for letting us play Ping-Pong in class, but didn’t quite make the coefficient of friction stick.

Active learning has impact far beyond physics. A meta-analysis compared the effects of lecturing and active learning on students’ mastery of the material, cumulating 225 studies with over 46,000 undergraduates in science, technology, engineering, and math (STEM). Active-learning methods included group problem solving, worksheets, and tutorials. On average, students scored half a letter grade worse under traditional lecturing than through active learning—and students were 1.55 times more likely to fail in classes with traditional lecturing. The researchers estimate that if the students who failed in lecture courses had participated in active learning, more than $3.5 million in tuition could have been saved.

It’s not hard to see why a boring lecture would fail, but even captivating lectures can fall short for a less obvious, more concerning reason. Lectures aren’t designed to accommodate dialogue or disagreement; they turn students into passive receivers of information rather than active thinkers. In the above meta-analysis, lecturing was especially ineffective in debunking known misconceptions—in leading students to think again. And experiments have shown that when a speaker delivers an inspiring message, the audience scrutinizes the material less carefully and forgets more of the content—even while claiming to remember more of it.

Social scientists have called this phenomenon the awestruck effect, but I think it’s better described as the dumbstruck effect. The sage-on-the-stage often preaches new thoughts, but rarely teaches us how to think for ourselves. Thoughtful lecturers might prosecute inaccurate arguments and tell us what to think instead, but they don’t necessarily show us how to rethink moving forward. Charismatic speakers can put us under a political spell, under which we follow them to gain their approval or affiliate with their tribe. We should be persuaded by the substance of an argument, not the shiny package in which it’s wrapped.

To be clear, I’m not suggesting eliminating lectures altogether. I love watching TED talks and have even learned to enjoy giving them. It was attending brilliant lectures that first piqued my curiosity about becoming a teacher, and I’m not opposed to doing some lecturing in my own classes. I just think it’s a problem that lectures remain the dominant method of teaching in secondary and higher education. Expect a lecture on that soon.

In North American universities, more than half of STEM professors spend at least 80 percent of their time lecturing, just over a quarter incorporate bits of interactivity, and fewer than a fifth use truly student-centered methods that involve active learning. In high schools it seems that half of teachers lecture most or all of the time.* Lectures are not always the best method of learning, and they are not enough to develop students into lifelong learners. If you spend all of your school years being fed information and are never given the opportunity to question it, you won’t develop the tools for rethinking that you need in life.

     Steve Macone/The New Yorker Collection/The Cartoon Bank; ? Condé Nast

THE UNBEARABLE LIGHTNESS OF REPEATING

There’s only one class I regret missing in college. It was taught by a philosopher named Robert Nozick. One of his ideas became famous thanks to the movie The Matrix: in the 1970s, Nozick introduced a thought experiment about whether people would choose to enter an “experience machine” that could provide infinite pleasure but remove them from real life.* In his classroom, Nozick created his own version of an experience machine: he insisted on teaching a new class every year. “I do my thinking through the courses I give,” he said.

Nozick taught one course on truth; another on philosophy and neuroscience; a third on Socrates, Buddha, and Jesus; a fourth on thinking about thinking; and a fifth on the Russian Revolution. In four decades of teaching, he taught only one class a second time: it was on the good life. “Presenting a completely polished and worked-out view doesn’t give students a feel for what it’s like to do original work in philosophy and to see it happen, to catch on to doing it,” he explained. Sadly, before I could take one of his courses, he died of cancer.