字幕表 動画を再生する 英語字幕をプリント (Bawn) Seeing someone yawn is all it takes to get me yawning. In fact seeing someone yawn or hearing the word or reading the word is enough to get half of healthy adults yawning Are you yawning now? Yawning is an example of emotional contagion, a phenomenon in which we tend to share the feelings of the people around us Of course yawning isn't the only behavior that's contagious. Sitcoms use laugh tracks because hearing other people laugh can be hard to resist (Laughter) Even if the show isn't funny. And when a baby in a hospital starts crying look out, because others within earshot will also start crying. We also copy less obvious signals from other people such as posture, speech patterns and facial expressions. Emotional contagion and mimicry may form the basis of empathy. They help us to intuit the thoughts and feelings of the people in our social circle. And children under four are actually less prone to contagious yawning, as are children and adolescents on the autism spectrum. Faces tell us a lot about what others are thinking and feeling and people with autism tend to focus less on faces and miss a lot of important social cues. But even youngsters with autism start to yawn when they're coaxed into looking at the eyes and sometimes the mouth of a yawner. Evidence from chimpanzees suggests that yawning spreads when empathy exists between two chimps. Scientists showed chimps videos of either familiar animals or strangers yawning. The observers were much more likely to yawn when they saw a familiar chimp. We feel more empathy for people in our social groups than for strangers. And the brain mechanisms that support contagious yawning may help maintain relationships too. Even though it can be annoying, contagious yawning is probably a sign of good social skills. So don't hold back on the yawns. Your friends might thank you for it. For Scientific American's Instant Egghead (Yawn) I'm Sandra Upson.