By Katie Camero
Watching a movie with a friend can make you feel closer to that person, and more likely to hang out with them in the future. The same, it turns out, is true of chimpanzees.
Researchers analyzed 36 pairs of chimpanzees in the Ngamba Island Chimpanzee Sanctuary in Uganda. They led the apes—two at a time—into two adjacent, caged rooms with a closed door between them. The scientists then played several 1-minute videos of baby chimps swinging on tree branches on a computer screen. In one trial, the apes watched one screen placed outside of their rooms together. In the other trial, the team added a screen and put a plastic barrier in between them, blocking the apes from watching the same video together. An eye-tracking camera was used to monitor what the apes were looking at as the videos played, with red dots showing their shifting focus (as seen in the video above).
When the videos ended, the researchers opened the door separating the chimps’ rooms. The apes spent about seven more seconds in the same room with each other after watching the videos together than when they watched the videos separately. They also only groomed each other when they had watched the video together, the team reports today in the Proceedings of the Royal Society B.
In a separate experiment, the researchers paired apes with a human instead. They found that the apes were more motivated to approach the human, who sat on the other side of the cage, after watching the video with them—approaching them 12 seconds faster, on average—than when the two species watched the video separately.
The scientists say apes don’t seek out shared experiences just to connect with others, like humans do. But they claim their study is the first to suggest apes have some of the psychology required to do so. More studies need to be done to see whether such short-term interactions, like sharing a video, strengthen great ape relationships in the long run, the team notes.