Health and Medicine
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It’s perhaps one of the greatest injustices of human bodily functions that the yawn has become so stigmatized in social settings. Crack one out and you’ll likely receive accusations of being bored or rude. It seems ironic, really, because the science of yawning tells us that, if anything, it’s a sign you’re trying harder to pay attention.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.That’s what we discovered when we sat down with Dr Andrew Gallup, Teaching Professor of Behavioral Biology at Johns Hopkins University and a bit of an expert in yawning. We wanted to find out why this open-mouthed action seems to be so incredibly catching, and discovered along the way that there’s a hell of a lot going on when we yawn.
What is yawning?
AG: Yawning is an extended stretch that's localized to the skull, and what that does is it functions to increase blood flow to the brain. It introduces arterial blood supply while simultaneously flushing away venous return, and this likely has important functions in arousal and transitions in behavioral states across diverse species.
Do all animals yawn?
AG: Not all animals yawn, but it seems that all vertebrates yawn or show very similar yawn-like gaping patterns with their jaw. This yawning behavior has been documented in fish, amphibians, reptiles, birds, and mammals. So, it seems that it likely evolved initially within jawed fish, and that subsequently it has been conserved within the vertebrate lineage.
Why is yawning contagious?
AG: We are only really beginning to uncover why yawning is contagious, but we do know that in humans – and a growing number of non-human animals – that seeing or hearing other individuals yawn increases the tendency for observers to yawn. So, the proximate or underlying mechanisms for contagious yawning are merely detecting this action in others and in humans. This can even be initiated by thinking about yawning or reading about yawning.
Now, why that takes place remains unclear. It could be, for example, that contagious yawning is simply a byproduct of the evolution of other highly sophisticated mechanisms associated with social cognition in group living, where we pay really close attention to the behaviors of conspecifics, or the members of our own species, and we would begin to mimic them and copy these responses in an unconscious way to facilitate collective behavior, synchronization, and group movement.
Or, it could be that contagious yawning is, in fact, adaptive in the sense that, again, it may facilitate those processes of coordinated movement and synchronization within a group, perhaps in ways that enhance survival and reproduction by, for example, potentially enhancing vigilance to potential outside threats. Or, again, just synchronizing group behavior and promoting safety within groups.
Why are we more likely to catch yawns from people we know?
AG: The most notable interpretation is that contagious yawning may be linked with empathy. If empathy is defined in part by our tendency to be affected by and share the emotional and behavioral states of others, then perhaps contagious yawning is a very basic form of empathic processing.
A number of studies have examined this connection and found support for it in varying degrees. Initial studies showed that the tendency to yawn contagiously among humans was, in fact, positively correlated with how people scored on different measures of empathy, and the fact that we're more likely to yawn in response to close friends and family members is consistent with that view.
However, an alternative explanation for these biases in contagious yawning as a function of social closeness comes down to attention. So, we're much more likely to attend to and look at members of our family and our close friends when we're in close proximity to them. However, we have a tendency to avert our gaze and avoid social attention towards individuals that we don't have a strong relationship with.
Do you yawn all day learning about this stuff?
AG: I used to when I first began to study yawning and I was writing papers about yawning and thinking about it a lot. I found myself yawning excessively by myself, but I've kind of grown a habituation to it. I'm less sensitive to contagious yawning, at least in those contexts of reading about it and thinking about it. I don't think my tendency to yawn in response to others has changed in real-life interactions.
Why do you think people get funny about yawning?
AG: Studying the social stigma of yawning is fascinating to me. It doesn’t make any sense why anyone should be insulted when someone yawns in front of them. To me, it’s spontaneous, it’s uncontrollable. You certainly aren’t insulted if someone hiccups or someone sneezes in front of us, as long as they cover their mouth when they do so.
Can yawns be stopped?
AG: There are a few ways that you can stifle yawns if you find that it’s socially appropriate to do so. One, if you feel a yawn coming on, if you take a deep nasal inhalation and then maybe another one after that, this has been shown to inhibit the yawning response. Another behavior that reduces the incidence of yawning is chewing on gum.
This interview first appeared in Issue 30 of our digital magazine CURIOUS. Older issues of CURIOUS are free for all users. To access new issues, become an All Access Member. You can find all episodes of We Have Questions here.
