Watch the video above. Did you yawn? Contagious yawning occurs when someone around you yawns and you yawn in response. It's an involuntary response. Humans do it, and so do chimpanzees. In chimps, researchers have linked the behavior with empathy, so researchers studying empathy in chimps sometimes end up studying contagious yawning, as did a group of Emory University primate scientists who recently created an animated chimp for their experiments.
Animal behavior researchers in recent years have realized that animations and robots can make for better experiments. These fake animals perform the same action in the same way each time on command, something that real animals never do. But will the live animal respond to a cartoon in the same way it would to another live animal? It's the first question that has to be answered if a scientist wants their experiments to be legitimate. So to answer that question in chimpanzees, the Emory University researchers turned to the contagious yawning experiment. Their results appear in the Proceedings of the Royal Society B.
The Emory scientists created 3-D animations of a chimp, some in which a cartoon chimp yawned widely and others in which a control cartoon chimp made other, non-yawning movements with its mouth. They then played the animations for 24 live chimpanzees. The live chimps were far more likely to yawn in response to the yawning cartoon chimp than when they saw the control cartoon chimp.
This is an introductory experiment that the researchers say has demonstrated the utility of animations in behavioural experiments.
In his future work, Campbell would like to pin down exactly how these measurable behaviours are related to the more difficult to measure phenomenon of empathy.
"We'd like to know more about behaviours related to empathy, like consolation - when an individual does something nice to the victim of aggression," he told BBC News.
The researchers don't think that the chimps were completely fooled by the animation and thought that they were looking at real chimpanzees. But the experiment does bring up interesting questions about how children interpret cartoons on TV or in video games.