Why do we yawn?
It is probably a pretty safe bet that you have found yourself yawning after seeing someone else yawn before you. Certainly math class can be boring and nightlong marathons of fragging strangers on Call of Duty can lead to a short night’s rest. Boredom and tiredness are typically the two most commonly accepted reasons we yawn for people that don’t study the mattter. For many years it was suspected that yawning, a reflexive action in which there is little control over, is the body’s way of restoring o2 levels and flushing the system of co2, though studies have indicated for years this likely isn’t the case.
The most recent and arguably the most logical explanation comes from Andrew C. Gallupa and Gordon G. Gallup Jr. of State University of New York in their 2007 study on yawning. The comprehensive study concluded that the act of yawning is the body’s way of cooling warm brains. Increased brain temperature is associated with many effects, several of which mimic (or perhaps even cause) of the effects also associated with feeling tired (drowsiness, for example). It seems that yawning is nothing more than temperature regulation. Fine. Easy enough. But what the heck does temperature regulation have to do with contagious yawning? Lets dig a little deeper. But first…
In just two short paragraphs of writing on the topic, I have yawned several times (Have you? Don’t lie). Lets try an experiment. Watch this video of a cute kitten yawning and tell me you don’t yawn as well. Is this article making you yawn? Leave a comment below and tell us how many times you yawned.
Admit it, you yawned (or at least went “Awwwww”).
Who contagious yawns?
Watch out for those teeth! A Macaques monkey yawning.
Stumptail macaques yawn in responses to other macaques on video
A 2006 study by Anika Paukner and James Anderson (University of Stirling) discovered that macaques demonstrate a significant increase in yawning of after the chimps were shown videos of other chimpanzees yawning.
How they did it
22 macaques were shown videos of other macaques yawning and videos of other macaques making non-yawning facial expressions (control).
The results
The results showed an increase of nearly double (4.7 vs 10 yawns, on average) when macaques were shown the yawn videos demonstrating that contagious yawning is not environment-related (as the yawns were on video) but instead must something psychological.
A 2008 study by Joly-Mascheroni, Senju and Shepard explored whether or not dogs were effected by seeing a human yawn. Their findings indicated that dogs are in fact responsive to human yawns.
How they did it
29 domesticated dogs were placed in view of a human subject. The human subject either yawned (a real yawn) or mimicked a yawn (control).
The Results
Over several trials two simple results surfaced.
- 21 out of 29 dogs were responsive to human yawning in that if they “caught” a human yawning, the response was a yawn themselves.
- The dogs were not responsive to the “fake” (control) yawn. Only real yawns elicited a response yawn.
In another study, researchers Wilkinson, Sebanz, Mandl and Huber prove that while some animals contagious yawn (such as chimpanzees and domesticated dogs), the red-footed tortoise does not.
How they did it
Several red-footed tortoises were conditioned to yawn at the site of a red square that was flashed in their face. The yawning response to this stimuli was predictable and reliable. A second group of red-footed tortoises were placed in view of the experimental tortoises and were observed.
The Results
There were three possible situations in which a red-tortoise would respond to a yawn.
- Seeing a red-footed tortoise yawn in response to the conditioned stimuli
- Seeing a red-footed tortoise yawn naturally (no external stimuli)
- Seeing a red-footed tortoise make the motion of yawn (a fake yawn)
In all three scenarios, there was never an observation of a red-footed tortoise yawning in response to another red-footed tortoises yawn. In other words, the red-footed tortoise does not contagious yawn!
What do The Animal Studies Tell Us?
Domestic dogs yawn in response to a human yawn and tortoises don’t respond to their own kind’s yawns. Neither are primates but domestic dogs do demonstrate a very high level of social interaction with humans. Could this be why dogs are likely to yawn in response to a human yawn? It is widely accepted that dogs have co-evolved alongside humans. Interestingly, wolves are not as socially responsive to humans as dogs are and this is likely because dogs and wolves have evolved separately for many thousands of years. It’s also worth pointing out that the video studies indicate that contagious yawning is not environmentally driven. Therefore, contagious yawning is not merely an illusion caused by a warm room (which would cause several individuals to have warmer brains and need cooling via a yawn).
These facts indicate that the act of contagious yawning is a socially driven-response, but what social skill is at play here?
Empathy as an Explanation for Contagious Yawning
One of the few positives that can come from disorders of the brain is that they can give us insight into how a normal functioning brain works. For example, brain lesion studies have been one of the most useful ways of studying brain functions. Perhaps the most famous example of this is the story of Phineas Gage, who suffered a traumatic work accident in which a 4in diameter rod was forced through his skull. The damage to his frontal cortex along with a dramatic change in his social inhibitions and odd behavior in the years following the accident resulted in some of the first and to this day most useful insights into the connection between the frontal cortex and human behavior.
In the same sense, we can look at human behavior disorders as a window to the psychological relationships behind related-behaviors. In the case of contagious yawning, many studies are leading us down a road in which empathy appears to be the cause. Some of the most insightful work to this end are studies related to childhood development and autism.
Autism and Empathy
Of the several symptoms of autism, the hallmarks are impaired non-verbal social interaction and a lack of social-awareness/empathy towards others. Given that this is a widely studied and overwhelmingly accepted fact, let us now explore contagious yawning among autistic patients.
Contagious and spontaneous yawning in autistic and typically developing children
In a 2009 study by Fiorenza Giganti and Maria Esposito explored the difference between autistic children (both high and low functioning) and normally developed children and their responses to human yawn.
How they did it
The parents of the three groups (normal, autistic high functioning & autistic low functioning) were first asked to observe and record the number of yawns in their children over the course of a day. This information was then used as a baseline. In the second part of the study, the children were shown videos of young adults yawning (stimuli) and making other facial expressions (control). Clips were random (smile or yawn) and standard in length (5s). Children were also given audio of people yawning.
The Results
In the first part of the study, there was found to be no significant difference in the number of natural yawns by any of the groups of children regardless of development. In the second part of the study, however, the non-autistic children were significantly more likely to yawn in response to both the visual and audio yawns while autistic children were significantly less likely in the video sessions (low-functioning autistic children were significantly less likely than high functioning-autistic children as well). In the audio-only sessions, both groups of autistic children showed virtually no contagious yawn, in contrast to their normally developed counterparts.
Psychological influences on Yawning in Children
In another simple study, James Anderson and Pauline Meno explored the yawning behavior of healthy children ranging in age from 2 to 11 years old to study contagious yawning in children.
How they did it
87 children ranging from 2 to 11 years old were shown videos of adults yawning 17 times and smiling 17 times. Children were asked to clap when they saw someone yawn (this helped ensure that younger children were able to recognize a yawn).
The Results
The data from the study suggests that children under the age of 6 will not reliably yawn in response to seeing another human yawn. In other words, contagious yawning does not exist in children under the age of 6.
Conclusions
One of the differences between humans and most other species is the advance social skills that develop in adults. This development does take some time and it has been suggested that advance empathy does not begin to really take shape until the age of 6 or 7. Additionally, it is well documented that autistic children lack basic empathetic skills. These facts alongside the above contagious yawning studies seem to indicate that contagious yawning is directly related to empathy. Since empathy is an advanced social skill, of which few animals in the kingdom have (that is both empathy and advance social skills), it is also not a surprise then that contagious yawning is lacking in the animal kingdom outside of a specific set of highly-advanced animals (humans included).
The only logical conclusion to draw at this time is that we yawn in response to other’s yawns simply because we are empathetic. The reason that we are empathetic to other individuals yawns has yet to be explained but there are other behaviors that seem to also be contagious such as itching, smiling, and several other behaviors. Empathy is an important skill for physically weak (relatively) highly social animals that rely on each other. Without empathy, bad things can happen.
So, simply put, we are contagious to other people’s yawns because we are empathetic. If your wife doesn’t yawn when you do, you’ve been warned.