Did seeing that video make you yawn? If so, you just experienced one of the weirdest of human behaviors: the contagious yawn.
No one knows exactly what purpose yawning serves. We tend to do it more when we are sleepy or bored, and some scientists think it may help to make us feel more awake and attentive to our surroundings. Yawning might also affect the amount of oxygen in our blood, or help cool our brains when they get overheated.
Other theories argue that yawning serves a social purpose rather than a biological one. It tells other people about our mood and helps coordinate social behavior in a group. As a teacher, I’ve certainly found it a useful signal to wrap things up when my students start passing a yawn around the room.
Humans are not the only animals to yawn. Fish, birds and mammals all yawn too. And of course, so do our favorite animals here at Loyal, dogs!
Yawning in dogs may have the same physical functions as in humans, but the social purpose seems a bit different. Dogs do yawn before and after resting, suggesting yawns can signal sleepiness or help with waking up after a nap. However, yawning is also a well-known sign of stress and anxiety in dogs. They may yawn when nervous (like at the vet), or as a signal of appeasement- telling another dog or a human that they aren’t a threat.
So what about contagious yawning? Humans often yawn when they see or hear, or even read about another person yawning. I have certainly yawned a lot while working on this post. But why do we do this?
Research in humans suggests contagious yawning may be a sign of empathy, a reflection in our own behavior of how we sense another person is feeling. The more connected we are to someone, the more likely we are to catch their yawns. People catch yawns from family members or friends more than from strangers. And people who have more difficulty reading the feelings of others, such as children under five years old and people with some types of autism, appear to be less susceptible to contagious yawning. So what about other animals, including our canine companions? Do they experience contagious yawning?
It won’t surprise you to learn that our closest evolutionary relative, the chimpanzee, exhibits contagious yawning. A few other primates do as well. Most other mammals don’t appear able to catch a yawn, but dogs are the exception. Dogs can catch yawns from other dogs, and from humans. Like us, they can catch a yawn in person or just from seeing or hearing one. And like humans, dogs are more likely to catch yawns from people or other dogs they know, suggesting that empathy plays a role in contagious yawning for dogs too.
So the next time you yawn, take a peek and see if your dog does too!
If you want to dive deeper into the science of yawning, here are some articles to get you started.
Guggisberg, A. G., Mathis, J., Schnider, A., & Hess, C. W. (2010). Why do we yawn? Neuroscience & Biobehavioral Reviews, 34(8), 1267–1276.
Krestel H, Bassetti CL, Walusinski O. Yawning-Its anatomy, chemistry, role, and pathological considerations. Prog Neurobiol. 2018 Feb;161:61-78. doi: 10.1016/j.pneurobio.2017.11.003. Epub 2017 Nov 29. PMID: 29197651.
Norscia, I., Zanoli, A., Gamba, M., & Palagi, E. (2020). Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis. In Frontiers in Psychology (Vol. 11).
Romero T, Konno A, Hasegawa T (2013) Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy. PLOS ONE 8(8): e71365.
Hoff, AE. (2001) Mouths wide open: Yawning as a communicative behavior in dogs. Master’s Thesis. Colorado State University, Fort, Collins, CO.