A history book can teach you a lot; a moving image gets inside your soul.

A.I. video generators are trained on a large data set that includes documentaries. They can ably imitate the visual vocabulary of the form — talking heads, sweeping shots and other elements we expect from authoritative films.

In this brave new world, no claim that a video is real will ever be fully persuasive.

But with documentaries, there’s also a kind of social contract

That phenomenon has a name: “liar’s dividend,” a term coined by two law professors in 2019. The idea is simple. We’re becoming more aware of how easy it is to create convincing fake videos, which means people who claim real videos are fake are becoming more persuasive, too. If they’re caught on video but claim the video is A.I., we’re more likely... See more