You're in a conversation with another person and he casually yawns. As you wonder whether he's bored with the discussion, you find that you're yawning, too. A man walking by, sees you yawn, and pretty soon he yawns. It's carried on and on, passing from one person to another in a domino effect. Science is still investigating exactly what makes us yawn, but it's a well-known and little-studied fact: Yawning is contagious.
We know that much of yawning is due to suggestibility -- it's infectious. You don't need to actually see a person yawn to involuntarily yawn yourself; hearing someone yawn or even reading about yawning can cause the same reaction. Chances are you'll yawn at least once while reading this article.
But contagious yawning goes beyond mere suggestibility. Recent studies show that the phenomenon is also related to our predisposition toward empathy -- the ability to understand and connect with others' emotional states. It sounds strange, but whether or not you're susceptible to contagious yawning may actually be related to how much empathy you feel for others.
Empathy is an important part of cognitive development. We learn from an early age to value ourselves based on the amount and type of empathy our parents display, and developmental psychologists have found that people who weren't shown empathy by their parents struggle later on in life. A lack of early empathy has been shown to lead to the development of sociopathic behavior in adults [source: Montana].
So empathy is important, sure, but how could it possibly be related to contagious yawning? Leave it up to psychologists at Leeds University in England to answer that. In their study, researchers selected 40 psychology students and 40 engineering students. Each student was made to wait individually in a waiting room, along with an undercover assistant who yawned 10 times in as many minutes. The students were then administered an emotional quotient test: Students were shown 40 images of eyes and asked what emotion each one displayed.
The results of the test support the idea that contagious yawning is linked to empathy. The psychology students -- whose future profession requires them to focus on others -- yawned contagiously an average of 5.5 times in the waiting room and scored 28 out of 40 on the emotional test. The engineering students -- who tend to focus on things like numbers and systems -- yawned an average of 1.5 times and scored 25.5 out of 40 on the following test. The difference doesn't sound like much, but researchers consider it significant. Strangely, women, who are generally considered more emotionally attuned, didn't score any higher than men [source: The Telegraph].
These findings support what neurologists found through brain imaging: Contagious yawning is associated with the same parts of the brain that deal with empathy. These regions, the precuneus and posterior temporal gyrus, are located in the back of the brain. And although the link between contagious yawning and empathy has been established, explanations for the link are still being investigated.
Researchers are looking into the world of development disorders and at higher primates for answers to this riddle. In the next section, we'll look at the connection between empathy and animals, and we'll find out how autism affects empathy.
Primate Yawing, Autism and Contagious Yawning
Yawning may serve a number of functions, and these functions might be different for different animals. Humans aren't the only animals that yawn -- even fish do. But only humans and chimpanzees, our closest relative in the animal kingdom, have shown definite contagious yawning.
One study, conducted in Kyoto, Japan, observed six chimps in captivity. Chimps were shown videos of other chimps yawning, along with chimps that opened their mouths but did not yawn. Of the six, two chimps yawned contagiously a number of times. Even more interesting, like their human counterparts under age 5, the three chimp infants showed no susceptibility to contagious yawning [source: MSNBC]
Autism and Contagious Yawning
This may be related to the fact that empathy is taught and learned. If contagious yawning is the result of empathy, then contagious yawning wouldn't exist until the ability to empathize was learned. But what if empathy is never developed? Another study, lead by cognitive researcher Atsushi Senju, sought to answer that question.
People with autism spectrum disorder are considered to be developmentally impaired emotionally. Autistics have trouble connecting with others and find it difficult to feel empathy. Since autistics have difficulty feeling empathy, then they shouldn't be susceptible to contagious yawning.
To find out, Senju and his colleagues placed 48 kids ages 7 to 15 in a room with a television. Twenty-four of the test subjects had been diagnosed with autism spectrum disorder, the other half were non-autistic kids. Like the Kyoto chimp study, the test subjects were shown short clips of people yawning as well as clips of people opening their mouths but not yawning. While the kids with autism had the same lack of reaction to both kinds of clips, the non-autistic kids yawned more after the clips of people yawning [source: BPS].
But there could be another interpretation to Senju's findings. Autistics tend to focus on the mouths of people with whom they interact. But contagious yawning is thought to be cued -- not by movements in the mouth area -- but by changes to the area around the yawning person's eyes. This could explain why autistics are less susceptible to contagious yawning -- perhaps they're just missing the cues.
However, that notion is undermined by another study. Conducted by researchers at Yale University, this study examined the reactions of autistic adults while they watched emotionally charged scenes from the movie, "Who's Afraid of Virginia Woolf?" Researchers found that those autistics who watched the eyes of the characters didn't register any more emotional reaction than those who focused on the mouth. This indicates that contagious yawning amounts to more than just cues; the autistics who watched the eyes received little information from the cues they found there [source: Yale].
It's become pretty clear that contagious yawning is linked to empathy. But why? Perhaps the best explanation for why we yawn, as well as why yawning is contagious, can be found around the watering hole on the savannah tens of thousands of years ago.
Some scientists believe that yawning is an involuntary response to a stressful situation: When we yawn, we increase the blood flow to the brain, thus making us more alert. Contagious yawning may be a method of quiet communication by which our ancestors spread the word that a hungry lion was nearby. Fear is an emotion with which we can empathize, and yawning may serve as a cue by which we spread that fear.
So, how many times have you yawned?
For lots more information on contagious yawning and empathy, including related articles and links, visit the next page.
Related HowStuffWorks Articles
More Great Links
- Fleming, Nic and Highfield, Roger. "Contagious Yawning 'Shows More Empathy With Other People's Feelings." Telegraph.co.uk. September 10, 2007. http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/09/10/sciyawn110.xml
- Montana, Stephen, Ph.D. "Understanding Empathy." St. Luke Institute. May/June 2003. http://www.sli.org/page_108_understanding_empathy.html
- Peart, Karen. "Results of Autism Research May Provide a Key to Determining Severity of Individual's Condition." Yale Bulletin and Calendar. October 25, 2002. http://www.yale.edu/opa/v31.n8/story15.html
- Randerson, James. "Why Engineers Yawn Less Than Psychologists." The Guardian. September 11, 2007. http://www.guardian.co.uk/science/2007/sep/11/1
- Seward, Liz. "Contagious Yawn 'Sign of Empathy.'" BBC. September 10, 2007. http://news.bbc.co.uk/2/hi/science/nature/6988155.stm
- "Children With Autism Are Immune To Contagious Yawning." British Psychological Society. September 7, 2007. http://bps-research-digest.blogspot.com/2007/09/children-with-autism-are-immune-to.html
- "Chimps Just Can't Help Yawning Either: Study Finds Behavior Just As Contagious As In Humans." MSNBC. July 26, 2004. http://www.msnbc.msn.com/id/5518753/
- "What is Empathy?" PsyBlog. http://www.spring.org.uk/2007/01/what-is-empathy.php