What is a cow doing behind Brad Pitt?

I didn’t see the cow in Babylon either. Let me explain: a few days ago, Doctor Frusna — a Twitter account specializing in cinema — brought back a clip promoting the movie Babylon. The director, Damien Chazelle, says that there is a moment when a cow appears behind Brad Pitt. Chazelle laments, with more or less feigned indignation, that no one notices the cow, “not even the film editors,” because everyone is staring at Brad Pitt’s face.

But there’s a bit of a catch. Although there is in fact a cow, mooing in all its cow glory, the animal is in the background, slightly blurred, and just one of the many other characters that feature in the movie’s extravagant opening party scene. But the fact that no one spotted it is a reminder of a classic experiment in human attention. In 1999, Daniel Simons and Christopher Chabris recorded a video in which two teams, one dressed in black and one in white, passed a basketball to one another. When showing the video to participants, they asked them to count how many passes the white team made. All very easy, but half of the participants did not notice a small detail: in the middle of the recording, a person dressed as a gorilla calmly walks among the players and even stops to beat their chest.

This makes sense and is even a good sign: as essayist and popularizer Michael Shermer explains in The Believing Brain, we could not concentrate effectively on any task if we were aware of everything that was happening around us. That’s why we don’t see the cow or the gorilla, and that’s why, as some commentators on the Doctor Frusna video point out, we also don’t notice most of the mistakes in the movies, for example, the whiskey glasses that go from empty to full from shot to shot or, in the case of Mission Impossible: Fallout, the pocket on Henry Cavill’s shirt that magically appears.

But this can also have negative consequences, beyond our inability to spot cows. As Kathryn Schulz points out in her book Being Wrong: Adventures in the Margin of Error, our limited attention can cause traffic accidents, lead to unreliable eyewitnesses and leave us open to pickpockets: For example, while one person diverts our attention, the other diverts our cell phone to their pocket.

Magicians also know how to take advantage of these limits: Shermer himself gave an example of this on his Twitter account on Saturday, responding to a video of a Spanish magician seemingly teleporting four volunteers. Shermer did not reveal the secret to the magician’s trick, but rather the psychological mechanism behind it. He did this via a classic online game: in a tweet, he showed some cards and asked us to choose one of them. In the following tweet, he made the card we had selected disappear.

The card disappears, because the second tweet does not contain any of the same cards from the first. They have each been replaced by one that looks very similar. We don’t realize this because we weren’t paying attention to all the cards, just the one we had selected.

This does not mean that we should always pay more attention to everything. We would become lost in a tidal wave of details that would end up driving us crazy. And in exchange for what? Spotting a cow in every 2,000 or so movies? But perhaps it is worth paying attention to the questions being asked of us: for example, in the video of the gorilla, we are asked to count the passes. Without this instruction, it is much easier to see the animal. In other words, if someone wants to hide something, it is often enough for them to focus our attention on other matters and let the gorilla walk calmly by. Perhaps that’s how some politicians manage to skirt uncomfortable topics...

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