Let’s cut right to the chase: Yawning is contagious. It’s one of those things that is just “known” and has been forever.
Much in the same way we instinctively understand that any man wearing white New Balance shoes with grass stains is a dad, we’ve come to expect that when someone yawns, someone else nearby will soon follow suit.
How do we know that yawning is contagious?
In addition to the cornucopia of modern research documenting the transference of the urge to yawn between not only people but animals, Aristotle was writing about the contagion of yawns as if it were old news. And that was, like, two hundred years ago at least.
So when we stumbled across some research sharply critiquing the claims that yawning is spread from one person to another, we decided to dive in and see what was really going on with these new reports.
When we stumbled across some research sharply critiquing the claims that yawning is spread from one person to another, we decided to dive in.
Now you’re just some theory that I used to know
The main question for the last thirty years in yawning science (yes, that’s a real thing) has not been whether yawning is contagious but rather why.
Most all research will indicate that yes, yawning is contagious, but at various levels of infectiousness based on age, sex, the presence of other people, the perception that you’re being watched, empathy levels, psychopathy or autism spectrum disorders, or even brain temperature.
In summary, we’ve seen that people tend to yawn after other people do so in front of them, but haven’t much of a clue why.
So, why is yawning contagious?
It’s a fascinatingly useless mystery, an enigmatic problem for the extremely bored or exceedingly curious to solve. It’s been that way for the past several decades, with dedicated scientists working to determine what drives the ancient observation of contagious yawning.
However, researchers Rohan Kapitány and Mark Nielsen have suggested that we may want to take a step back and reevaluate how we first arrived at the conclusion that one yawn begets another.
Their paper, “Are Yawns really Contagious? A Critique and Quantification of Yawn Contagion,” tells us that we may have been wrong about all of it.
Science writing, more so than other embodiments of the written word, can be particularly scathing and incisive in its dryness and matter-of-fact tone. We’ll let the author, in his own words, summarize his findings on the fidelity of previous experiments on yawn contagion.
“I found the written work to be dominated by strange and unreasonable methodological assumptions – some were an artifact of the history of the field, while the origin and purpose of others were less clear. This was when I became interested – here was a very ordinary phenomenon that was not clearly described, and could reasonably be dissected with various methodologies and statistics (which I was interested in cultivating).”
He continues, bringing to light some of the most obvious flaws he sees in past methodology:
- During what window of time can a yawn be contagious? One minute? Three minutes? Five?
- Some research used only one length of time, where other studies didn’t report any sort of time window.
- Do multiple yawns serve as a stronger trigger than just one?
- How do we know if one individual’s yawn is the result of another individual’s yawn and not just a spontaneous yawn that they would have exhibited regardless of a trigger yawn?
The pair is flummoxed with the state of yawning research, and have used both behavioral experiments and network models to help answer these burning questions.
Methods to the madness
Modeling: the yawn-inducing kind
The authors here have co-opted a style of statistical modeling most often seen in epidemiological studies: Agent-Based Modeling. Individuals are represented by nodes in a virtual space and can affect the behavior of those around them based on certain parameters.
In this computer model, Kapitány has programmed a bunch of people into a room, and he wants to see how their yawns will affect others in the space.
Setting up separate simulations in which yawns were and were not contagious, they examined how many spontaneous/baseline yawns happened, how many “response yawns” happened, and how many spontaneous yawns happened within a contagion interval (incidental yawns).
Incidental yawns are essentially those which we might incorrectly classify in the real world as a response yawn. It occurs in the proper time interval after another individual’s spontaneous yawn despite not being triggered by said spontaneous yawn. While nearly impossible to control for in nature, using a computer simulation allows us to see which yawns are truly responses and those which are incidental.
Incidental yawns are essentially those which we might incorrectly classify in the real world as a response yawn.
Behavior, Blindfolds, and Be-yawned
In addition to the computer simulations mentioned above, the team conducted a behavioral experiment on groups of Australian college students to study yawn contagion in the real world.
Small groups were placed in a circle facing each other and blindfolded – with Chopin blasting through their earbuds to prevent them from seeing or hearing one another. After a set period of time, the blindfolds were removed. Other groups had the process occur in the opposite order; initially, they were free to see the others in the group, then were blindfolded later. Yawns were measured via video and various controls put in place.
So, using a combination of behavioral modeling and computer simulations, what did the researchers find? Well, a few strange things.
Conclusions on yawning
Contagion is harder to establish than we thought
Perhaps the most interesting of the findings was this: even if we operate under the assumption that yawns are not contagious, it’s incredibly easy to look at the data and conclude that they are.
Running the network simulation with yawn contagion turned off, they found that about half of all yawns occurred within five minutes of another person yawning. Keep in mind, the network simulation was programmed in this situation so that one person yawning had zero impact on the probability of another person yawning.
Despite this, it seems pretty reasonable that someone in the real world may think they’ve found contagion when in reality coincidence has led them to the conclusion they aimed to see.
They found that about half of all yawns occurred within five minutes of another person yawning.
Let’s say we go with the simulation in which yawns are programmed to be contagious. If we assume a yawn that occurs within five minutes of a spontaneous yawn is a response yawn we’ll arrive at some troubling conclusions.
The two researchers found that while a third of yawns are a response to other yawns, about 40% appear to be contagious but are in fact just baseline spontaneous yawns. In other words, they happened to fall in the contagion time window by chance.
About 40% appear to be contagious but are in fact just baseline spontaneous yawns.
So, even if yawns are contagious, they’re less so than we had originally thought.
We yawn in clusters
According to their behavioral study, 95% of all yawns by an individual were followed by another of their own yawns within a span of five minutes. That might not sound relevant, but deviations from random or uniform behaviors throw a wrench in analyses that is hard to pull out. Additionally, it shows we’re far more likely to “catch” a yawn not from another individual, but instead ourselves.
We yawn more often in social settings…
…but it doesn’t mean yawns have to be contagious. In fact, we’re not entirely sure why this happens. There are plenty of possible explanations out there, but we really just don’t know.
Researchers in the study did find that those without blindfolds on in a group setting will yawn more often than those blindfolded.
They also showed that a spontaneous yawn does not reliably elicit a response yawn within a three-minute window. That’s huge. We’ve also already established that even if there were plenty of yawns in this time window, there’s a good chance these could be incidental as opposed to response yawns.
*Yawn* Is it over yet?
What we do know now is that we know far less about yawning than we originally thought.
Critique is necessary for progress, and these researchers provided it in spades. While one study cannot disprove thirty years of research and millennia of widely held beliefs, the paper does bring into question the validity of past research and some glaring issues that have been overlooked by others in the field.