Photo courtesy of John Young, via Flickr
Photo courtesy of John Young, via Flickr

How Monkeys Watch Movies and People Tell Stories

Movies — or good ones, anyway — manipulate us. A good director knows how to put scenes in a sequence that will attract our eyes, stir up our emotions, and ultimately connect those heightened feelings to cerebral associations, memories, and ideas. Good movies will tell a story and deliver a message. It’s why we watch them in the first place: to be moved.

This isn’t a new idea; it has been around since the early days of movie-making. One of the most famous examples of it comes from “Stachka” (or “Strike,” in English) a silent film made by Sergei Eisenstein in 1925. Stachka takes place in Russia in 1903. Its plot, in a nutshell: factory workers go on strike, asking for more money and fewer hours; the company rejects the terms; the workers are hungry, angry, rowdy; the military storms in, corrals all the workers into a big field, kills them all.

The movie is best known for a few scenes at the end, in which Eisenstein cross-cuts the workers running for their lives with graphic footage of cattle being slaughtered. It’s an intense couple of minutes, so click at your own risk:

The editing is powerful, which of course was Eisenstein’s intention. As he wrote soon after the movie’s debut, the montage is “snatching fragments from our surroundings according to a conscious and predetermined plan calculated to launch them at the audience in the appropriate combination, to subjugate it to the appropriate association with the obvious final ideological motivation.”

But just how well can a movie “subjugate” its audience? And does everybody fall under its spell in the same way?

A decade ago, neuroscientists probed these questions with the help of a brain scanner. While lying inside the machine, participants were asked to do nothing but watch a 30-minute clip of the 1966 western “The Good, the Bad and the Ugly.” Even though they could think about or look at anything they wanted, they had surprisingly similar patterns of brain activity and eye movements, the study found. This effect was more than just a consequence of everybody looking at the same visual image. In a different experiment, participants watched a lame, unedited, 10-minute clip of people at a concert in Washington Square Park in New York City. This time, participants’ brain activity was much less in sync than it was when they were watching the western.

“Typically when I watch a movie it seems like it’s all in my own volition that I’m noticing stuff,” says Asif Ghazanfar, a neuroscientist at Princeton University. “But really it’s all the director. And he can do that because he has some idea of what human understanding is, and how to manipulate human emotion and how our visual system operates.”

Ghazanfar’s lab uses monkeys to study visual and auditory perception. A few years ago, these movie studies got him thinking: The visual perception of monkeys is similar to ours in many ways. They recognize and follow moving objects on a screen. When watching movies of other monkeys, they can detect social hierarchies and sense emotion, such as fear. They’re even susceptible to the “uncanny valley” effect (which Ed can tell you more about).

Is it possible, Ghazanfar wondered, that monkeys would follow a film narrative like we do? Or is narrative-chasing a uniquely human skill? If the skill were shared with monkeys, “that would be really cool,” Ghazanfar says. “Then we could use movies to infer what their feelings were. Because they can’t tell us, obviously.”

To find out, Ghazanfar and his postdoc, Stephen Shepherd, tracked the eye movements of monkeys and people as they watched identical 3-minute clips from three films: the BBC’s “Life of Mammals,” Disney’s “The Jungle Book,” and Chaplin’s “City Lights.” The movies were converted into black and white and played without sound. As it turned out, humans and monkeys have similar cinematic tastes. Check it out:

Credit: Stephen V. Shepherd and Shepherd et al., Current Biology, 2010

“There was a surprising degree of overlap,” Ghazanfar says. The gaze paths of humans and monkeys overlapped 31 percent of the time. A small part of this correlation is due to our shared visual reflexes: Both humans and monkeys are attracted to bright spots. But the bulk of the overlap was driven by the two species’ shared interest in complex scenes, particularly faces, body movements, and social interactions.

But the researchers also found two intriguing differences between the monkey and human gaze paths. First, “humans appear to look at the focus of actor’s attention and intentions to a much greater extent than do monkeys,” Ghazanfar and Shepherd wrote in a fascinating review published in the film journal Projections. Second, “humans appear to pay attention to related details in a movie for much longer than monkeys do, suggesting that humans integrate events over time in a fundamentally different way.”

In other words, it seems that what makes people different is our ability to follow a narrative. Whereas monkeys look and react to scenes quickly, people fixate on one actor and integrate complex events over time. In a clip showing two monkeys, for example, people tended to look squarely on the monkey sitting quietly in the center of the screen. Monkeys, in contrast, looked at the more active second monkey, even thought it was jumping out of view of the camera. “Monkeys were reacting moment-by-moment instead of assembling and testing a narrative explanation for the scene before them,” the researchers wrote.

As someone who tells stories for a living, I relish the idea that narrative is central to what makes us human. The idea could plausibly explain a lot of the other skills that non-human animals don’t seem to have, such as language, music, imagination, and “mental time travel.” And, of course, why we so love the movies.