Jewish World Review
http://www.jewishworldreview.com | (KRT) Imagine if you could catch an infection just by watching a movie or perusing a novel.
Yawns are contagious like that. If they were dangerous, reading this story might kill you.
Fortunately, catching a yawn usually isn't harmful. In fact, new research suggests that yawning contagiously might function as a subconscious signal of empathy, communicating to others, "I'm with you, I feel your yawn."
"It's pretty weird, like the behavior of the other person has captured you," said psychologist Robert Provine. "It's probably a primitive way of coupling the behavior of people in groups, linking their physiology."
Contagious yawning is widely recognized as a real phenomenon. Scholars as far back as Aristotle commented on it, noting, "Like a donkey urinates when he sees or hears another donkey do it, so also a man yawns seeing someone else do it."
A series of experiments led by Provine in the mid-1980s verified yawning's infectious nature, demonstrating that even reading or thinking about yawns can trigger them. And just seeing a gaping mouth won't do, said Dr. Provine. When people see an open mouth that could be perceived as singing or yelling, they don't yawn.
"It seems to be the overall configuration of the face - the tilting head and stretch of the jaw, the squint of the eyes," said Provine, of the University of Maryland Baltimore County. "It really gets at issues of how do we perceive a face and what constitutes the self."
The new research supports a link between contagious yawning and a person's self-awareness and ability to empathize with others. Sixty-five college students watched videos of people yawning, laughing or displaying neutral facial expressions while being observed through a one-way mirror by scientists at the State University of New York at Albany. Then the subjects took tests designed to assess how well they process information about others and themselves.
People with schizophrenia or certain types of brain damage usually have trouble on these tests because the area of their brain that deals with processing information about the self is impaired. The contagious yawners in the study scored lower on tests for schizophrenia-like traits than noncontagious yawners and were better at recognizing social faux pas portrayed in stories, the researchers reported this summer in Cognitive Brain Research.
Contagious yawners were quicker to recognize images of themselves, suggesting that the right half of the brain controls how susceptible one is to contagious yawning.
"It could be a way of keeping groups of people in synchrony," said biopsychologist Steven Platek, lead author of the study. One member of the research team suggested that contagious yawning evolved as a subconscious pickup line.
"It's possible showing empathy may be a good strategy for keeping a mate," said Platek, now at Drexel University. "If you yawn at someone and they yawn back, you have immediate insight that they are paying attention to you."
There may be a link between contagious yawning and the way people think about - and relate to - themselves and others, adds Provine, who said the study is an "intriguing way" of getting at the basis of a social behavior. Renowned developmental psychologist Jean Piaget noted that humans don't start yawning contagiously until they are about 2 years old, the same age that they begin recognizing themselves in a mirror. And investigating whether contagious yawns infect people who aren't as tuned in to social cues, such as individuals with autism or schizophrenia, will be an important next step, said Provine.
But he and other researchers caution against putting too fine an edge on such an ancient urge.
"I think it's giving yawning more credit than yawning is due to say it's related to self-awareness," said anthropologist E.O. Smith of Emory University. "Maybe it's a signal to turn in for the night. That might be just as good an explanation as some of the more highfalutin possibilities."
Platek's work suggests that other critters with a conscious sense of self should respond in kind when flashed a yawn. But evidence of contagious yawning in such creatures is scant, said experimental psychologist Ronald Baenninger of Temple University. Chimpanzees and orangutans will use a mirror to investigate themselves, parting their hair or picking their noses, once they realize the image they see is their own. But these primates aren't obvious contagious yawners, said Baenninger.
"A lot of my students have looked for it in chimps, and sometimes it happens and sometimes it doesn't - it is not a sure-fire thing," he said.
Plain old yawning has been observed in a menagerie of animals, though. Most creatures with backbones are yawners. Some birds do it, as do fish, tortoises, cats and dogs.
A true yawn can be hard to find, or at least recognize. A baboon's open-mouthed grimace, originally interpreted as a yawn, is now seen as a teeth-baring threat gesture. So some scientists prefer to split yawns into "true" or "rest" yawns, and "emotional" yawns that send a signal, be it empathy or aggression.
True yawns, the kind that come on when you're drowsy, appear to be a means of keeping you awake, rather than a prelude to sleep, said sleep scientist Marie Hayes of the University of Maine, Orono.
"When you look closely, yawns stimulate you enough to keep you from falling asleep," said Hayes. "They are very arousing."
Babies have been caught yawning in the womb with ultrasound, and infants as young as 10 weeks premature also yawn. The action seems to invigorate the infants, keeping them awake or at least in the foggy middle ground of drowsy, reported Hayes and her colleagues last year in Developmental Psychobiology.
"It is clearly a way of stirring up things physiologically," said Provine. His experiments in the 1980s showed that yawning is not related to the amount of oxygen or carbon dioxide that someone is breathing. You can't have a satisfying yawn if your lips are taped shut, even though you are free to breathe through your nose, he said.
Whether contracted from someone else or not, yawning is followed by momentary alertness, however fleeting. Experiments that track heart rate have shown that yawning stimulates the body, said Baenninger.
"You are suddenly more vigilant, more active," he said.
Baenninger isn't convinced about a link between empathy and contagious yawning. But the new work does throw some interesting ideas into the mix that will spur further study, he said.
And the research is a good reminder of our more primitive biological roots, said Provine.
"Contagious yawning is in conflict with this idea of us being rational beings in total conscious control of fate," he said. "We are still part of the community that we think we've risen above."
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