An involuntary reflex that can be interpreted as rude in some cultures, as a sign of tiredness and boredom in others or as a signal of anxiety in non-human creatures. Everyone knows what yawning is, but what is yawning really? These are the questions keeping me up at night. Probably the reason I yawn a lot during the day. The irony is not lost on me.

Intro

A yawn. The response to any boring subject taught in school. Before or after an audible sigh of exasperation. Often seen as a symbol of tired people or non-humans. The universal signal for people to tell you that you should really go to bed or sleep more. Yawning however, has a couple of functions. Within the scientific world there seems to be a growing acceptance that spontaneous yawning helps neurovascular circulation and brain cooling (in other words, it helps refresh the brain and makes the blood flow in your brain). Studies show that people with warm necks yawn a lot more often than those with a cold neck. Yawning makes a relaxed and comfortable individual alert by getting the brain cooler, the heart-rate up and stretching the muscles.

A lot of hormones (way more than I am about to reveal) are involved in yawning and although we are still unsure of its actual purpose, there is a little we do now already. Both oxytocin (the cuddle hormone) and dopamine (the reward and focus hormone) are involved. A peak in oxytocin levels makes you yawn. Oxy, besides being a drug, is the hormone that gives you that warm and comfortable feeling when hugging and/or cuddling a loved one. It is exactly that state that triggers a response of dopamine to get you out of your relaxed state and make you alert and focused again. Yawning is what seems to indicate your body wanting to stay awake and aware of your environment.

Social Yawning

Not rude or impolite, yawning is a social cue, and an important one at that. Yawning is observed in all groups of air-breathing vertebrates (birds, mammals, reptiles). This means two things: 1) yawning is a very old thing, evolution-wise and 2) even cats that sleep for 20 hours each day, yawn. Why would cats yawn? Because yawning is something creatures do when they need to come out of a monotone, half-conscious state of being. When waking up, before going to sleep, if they get bored, while comfortably reading a book or when you lick your paw for the 25th time in as many seconds. As a cat sleeps a lot of hours, but not all in one consecutive go, they yawn a lot.

For other animals, such as primates (including humans), dogs and hyenas, yawning has a social factor as well. Yawning indicates an alteration in energy and motor state. It is used within social groups to show that the yawner is going to change in activity and awareness. This signal is observed by others within the group, who in turn yawn. Yawning is contagious and you can get from a member of the same species, or a member of a different one. This means watching you pet yawn, can make you yawn. The main theory about the contagiousness of yawning is that it’s a way to synchronize energy and activity within a social group.

And as it turns out, people that know each other (family and friends) will respond more to each other’s yawns than to stranger’s yawns. Within some mammals there is even a difference in response by sex. In multiple animal societies, the leading sex is less likely to mimic yawning than the following sex. In bonobo’s females mimic other, older females more than they mimic males. While in most other social groups, like lions and baboons, it is observed the other way. Now I know you all want to know what it’s like within humans. It’s males. Females respond to yawning more, while males are responded to more. Our society did hopefully evolve enough to not take yawning as the argument for who should be world leaders and who shouldn’t.

Summary

Yawning is not rude, it’s a sign that you are boring (monotone, change up the volume and cadence of your voice) or talking to a sleep-deprived individual.

Men don’t care if women yawn, women care if men yawn. Evolution is sexist, not me.

Dogs yawn because they want to stay alert and aware and not fall asleep.

Yawn can be interpreted as sign that you are comfortable and relaxed (even though your brain/body doesn’t want to be). If your loved ones yawn a lot around you, take it as a compliment, not an insult.

Weirdly, reading the word yawn or yawning in your head makes you yawn. Or that might just have been me, reading scientific articles about yawning.

Thank you for reading. I hope you have learned a lot about why you yawn. See you on Friday.