Why we often yawn when we see someone else doing it, is still unknown. But as a step in approaching the yawn's mystery, researchers at City St George’s University of London, have investigated how it affects chimpanzees.
The researchers let 14 adult chimpanzees watch a robot head that resembled a human. The robot contained about 30 small motors that functioned as muscles that controlled facial expressions, including yawns.
Each chimpanzee was allowed to observe the robot face for 15 minutes when it made different expressions, each ten seconds long. The chimpanzees were filmed during the time and the researchers noted how they reacted. They also noted if the chimpanzees lay down.
The results, which are published in Scientific reports, showed that 5 percent of the chimpanzees themselves began to yawn in response to the robot's yawn. Just as many also lay down. Some of them even made a bed before lying down.
According to the researchers, it is the first time one shows that mammals are infected with yawning by something non-human. They now want to proceed and see if other behaviors can also infect animals from robots.
