Rewatching Videos Can Lead to the Replay Illusion

What is the replay illusion?

From an evolutionary perspective, our ability to capture a unique moment in time and replay it over and over is relatively new. My research argues that our brains don’t fully correct for the fact that what we’re seeing is a unique event that we happen to be watching more than once, even when we know this intellectually. Instead, we confuse replay with repetition. My coauthors and I propose that as a result, an action you see more than once appears more prepared, more rehearsed, and less spontaneous—just as it would have to be in real life if it were truly being precisely repeated.

What are some everyday implications?

We find that certain actions, such as dancing, appear more skilled when replayed, because deliberately controlling your body to reproduce the exact sequence is central to what it means to be skilled in that domain. On the other hand, replaying someone’s spontaneous emotional reaction makes it look less spontaneous and more controlled, and thus less genuine. 

And it’s not limited to video. We find the same thing with audio, where replayed laughter sounded fake to participants, even when it was genuine.

Probably the highest-stakes place this might matter is the courtroom, where recorded evidence from body cams, surveillance footage, and cellphones gets replayed for jurors. In one of our experiments, we showed participants a clip from the TV show Cops in which a woman had hired a hitman to kill her husband. When the police told her he’d been murdered, she reacted with anguish. Participants who watched the clip multiple times were more likely to say she seemed guilty, and they perceived her reaction to look more contrived and less genuine.

The replay illusion also shows up in advertising. We showed another set of participants “real people, not actors” commercials—the kind built around a customer’s supposed first-time reaction to a product—and replay made them more likely to think the people in them were actually paid actors. That undercuts the whole pitch. So advertisers may want to be careful with testimonials and reaction-based ads, insofar as seeing the same one repeatedly can make it look staged or contrived. 

What’s going on underneath both these examples is that people don’t quite separate “I’m seeing this again” from “this person did it again,” and that perceptual residue appears to shape some surprisingly consequential judgments.

Can the illusion be corrected?

In the experiment involving the Cops clip, we tested this by asking half of the participants to report how many times they’d viewed the video before they judged the reactions of the woman, and that small bit of awareness appeared to reduce, and in some cases eliminate, the effect. 

Jurors are likely to be shown a clip more than once—and to pick up information with each viewing—so simply asking them to acknowledge how many times they’ve seen a video might help neutralize the illusion without giving up the value of replay.

Kristin Donnelly is associate professor of marketing at Chicago Booth.