Why is yawning contagious?

It’s easy to catch a yawn – you might even yawn while you’re reading this.It’s not just humans that yawn, but all kinds of verterbrates, even fish! But contagious yawning is rarer.Norman and Tegan unpack why we yawn in this live recording at the World Science Festival Brisbane.References:Yawning: no effect of 3-5% CO2, 100% O2, and exercise Brain size and neuron numbers drive differences in yawn duration across mammals and birds Excessive yawning and thermoregulation: two case histories of chronic, debilitating bouts of yawningDifferent yawns, different functions? Testing social hypotheses on spontaneous yawning in Theropithecus geladaWhy yawns are contagious—in all kinds of animals: Evolutionary biologist Andrew Gallup explains why we yawn after others Mirror neuron activity during contagious yawning—an fMRI study The mirror-neuron system If you enjoyed this episode, check these out!Why are some people right (or left) handed?Can consuming dairy really give you acne?Is daylight saving time bad for us?