As an undergraduate in 1977, I took a course on 20th-century European diplomacy with the historian Roderic Davison. The material was absorbing but challenging and I had to work hard to earn a B. Professor Davison’s lectures were unfailingly interesting, but after all these years I have only one specific memory from my time in his classroom.

He was describing the breakdown of German society during the Weimar Republic and explaining the lure of the Nazi movement under Adolf Hitler. Suddenly he reached into his breast pocket and pulled out a small black comb. With his right hand, he quickly combed his hair forward across his brow, then held the comb horizontally against his upper lip. His left arm he shot stiffly outward and began declaiming in German. Most of my classmates laughed at the unexpected impersonation of the Fuhrer. But I was shaken. For me, with my family history, Hitler was no laughing matter. Davison’s spoof upset me badly.

My response? I did nothing. I knew perfectly well that my professor had intended no offense. I didn’t think his behavior had been improper. I may have been taken aback — in today’s parlance, “triggered” — but I assumed that my discomfiture was my own problem. The lecture resumed, the course went on, and to this day I regard Professor Davison’s course as one of the best of my college years.

What brings that long-ago episode to mind is the latest poll of undergraduates conducted by researchers from the Challey Institute for Global Innovation at North Dakota State University. The annual survey, which involves 2,000 students at 130 colleges and universities nationwide, gauges the views of students on multiple subjects, including viewpoint diversity and how higher education is influencing their views.

What the new poll reveals is a generation of college students deeply committed to the belief that if they are offended, someone ought to be punished.

In one eye-opening finding, 74 percent of undergrads endorse the view that a professor who says “something that students find offensive” should be reported to the university. By a majority almost as lopsided, 65 percent believe that a fellow student who says something they consider offensive should be turned in. That informers’ mindset is especially pronounced among students who identify themselves as politically liberal, fully 85 percent of whom would report a professor who offends them. But even among self-identified conservatives, a solid majority — 56 percent — are of the same mindset.

After the fall of the Iron Curtain a generation ago, Americans were appalled to learn about the pervasive culture of betrayal that had taken root in East Germany, where hundreds of thousands of citizens informed on each other to the secret police. Yet the Challey Institute’s findings suggest that on American college campuses today, something similar is becoming normal. Indeed, the survey implies that most students not only believe that wrong-thinkers should be penalized, but that they are oblivious to the chilling effect created in such an environment.

In what at first glance seems like an encouraging finding, 72 percent of undergraduates report that their classrooms are places where “people with unpopular views would feel comfortable sharing their opinions.” Drill down into the data, however, and it transpires that it is overwhelmingly those students — the ones who say their classrooms are receptive to unpopular ideas — who also say that anyone making “offensive” comments should be turned in.

The survey doesn’t define the term “offensive” but instances of heterodox views on college campuses being silenced, shouted down, disrupted, vetoed by hecklers, or turned into firing offenses have become almost too numerous to count. And what is true of undergraduates, according to a report published by the Center for the Study of Partisanship and Ideology, is also true of advanced students: Express an opinion that others find offensive, and the consequences can be serious. The CSPI study found, for example, that 43 percent of American PhD candidates would back efforts to expel a hypothetical scholar whose research raised doubts about the benefits of racial and gender diversity.

Is it any wonder that, in academia as in society at large, self-censorship has grown pervasive? There is “a sustained campaign to impose ideological conformity in the name of diversity,” the historian Niall Ferguson has written. “It often feels as if there is less free speech and free thought in the American university today than in almost any other institution in the U.S.”

Perhaps the illiberal trajectory of American higher education can be reversed, though it seems quite a long shot. I only know that I’m grateful to have gotten my education before the politics of resentment and grievance became such unstoppable forces on campus. That was a golden age, though none of us knew it at the time.