Yawns always sneak up on me at the most inopportune times: when I’m trying to look alert and professional in a business meeting, when I’m attempting to appear engrossed in conversation with a friend I haven’t seen in a long time, or when I’m on a hiking trail, at the exact moment a fly decides to dive-bomb into my mouth (true story). Occasionally, I can nip a yawn in the bud, so as not to completely aggravate my coworkers or my dinner companion. But the minute someone else in the room yawns as well, all bets are off—my mouth opens wide, like a marionette’s controlled by a puppeteer, and I suck in as much oxygen as my brain can handle. I’ve always wondered why yawning seems to be contagious, and I’m not alone. In recent years, scientists have come up with all kinds of theories in attempts to get to the bottom of the phenomenon.
Some people can’t stop themselves from yawning when they see someone else doing it, either in person or on video. For others, just hearing a yawn can trigger them to follow suit. And for particularly susceptible individuals, the mere thought of someone else yawning can cause them to open up. In all of these circumstances, yawn contagion appears to be largely unconscious, according to a 2005 joint study by researchers from the Helsinki University of Technology (Finland), and the Research Centre Jülich (Germany). Their investigation determined that, in contrast with other types of physical mimicry, the human brain doesn’t consciously analyze and mirror the act of yawning when it’s observed—yet it directs us to yawn anyway. So what gives?
Most likely, these researchers surmised, the sight of someone yawning deactivates an area of our brains known as the left periamygdalar region. Among the participants in this study, all of whom were asked to report the severity of their desire to yawn in response to videos of other people yawning, the researchers noted an inversely proportional relationship between their urges and this deactivation effect. In other words, the more a participant was tempted to yawn, the less active his or her left periamygdalar region appeared to be. While the researchers were not able to extrapolate any further meaning from that pattern, it did establish that humans’ proximity to yawning individuals jump-starts an identifiable cerebral reaction.
Tired Minds Think Alike
Another group of scientists, from the University of Leeds, also explored the yawn-brain relationship and discovered that humans who are especially susceptible to yawn contagion appear to have a more keenly developed sense of empathy than those who are not. Posing as fellow volunteers, each researcher sat in a waiting room with one of the actual study participants and yawned ten times during a ten-minute span, while recording the number of times his or her companions yawned in response. These same subjects were then asked to complete an exercise designed to assess their empathetic skills, in which they noted the emotions present in a variety of pictures of eyes. The test indicated that the highest-scoring (most empathetic) individuals were the same people who had yawned the most times in response to the researchers’ yawning. For Dr. Catriona Morrison, the psychologist who led this study, these results confirmed that succumbing to yawning contagion “indicates an appreciation of other people’s behavioral and physiological state,” as she told the BBC News.
Robert Provine, a University of Maryland psychology professor and a renowned expert on yawning, takes this idea one step further, stating that when yawning catches on, it not only speaks to people’s desire for a shared human experience but also might transmit important survival messages. Provine explained to MSNBC that “yawning is ancient and autonomic. Maybe [contagious yawning is designed] to get everyone in the tribe to synchronize their states of activity, to increase the success of the tribe if everyone’s working together.” For instance, early humans may have used collective yawning as a method to coordinate their sleeping schedules and thereby ensure that they would all be awake and at their most productive at the same time.
Many animals yawn—including birds, snakes, cats, dogs, bears, and hippopotamuses—but most are unaffected by the yawn contagion that humans experience. In a 2004 study, however, Japanese scientists discovered that chimpanzees do exhibit this same tendency. The researchers showed six adult female chimps two sets of video scenes: some featuring other chimps yawning, the others depicting chimps in other open-mouthed (but decidedly not yawning) poses. On average, the chimps yawned ten times during and after the yawning videos, as opposed to only 4.7 times during and after viewing the other open-mouthed shots. Two of the chimps in particular, named Ai and Mari, demonstrated even more varied reactions to the two types of videos: Ai yawned twenty-four times, and Mari twenty-five times, in response to the yawning videos, compared with two and nine times, respectively, while they observed the non-yawning images.
Not only do these numbers evidence a yawn contagion rate similar to that of humans among the chimp test subjects, but the Japanese scientists believe the statistics are linked to the fact that chimps display more obvious empathetic tendencies than other types of apes and monkeys do—further substantiating the University of Leeds researchers’ proposition that empathy and yawn contagion are interrelated, and yet another way in which we humans and our primate ancestors are alike.
It’s Only Natural
What all this research goes to show is that for most people, attempting to resist yawn contagion is as futile as trying to squeeze water from a rock. So the next time you’re sitting in a conference room and catch one of your colleagues with a gaping mouth, go ahead and let out a big yawn of your own with pride (and then send your CEO a link to this article so you don’t get in trouble). And if people ever harass you about why it’s so hard for you to control your physical impulses, just say, “I can’t keep my mouth shut because I’m a deeply empathetic person. What’s your excuse?”
Updated December 27, 2010