Ho-Humdinger: Yawns Perk Up Brain, Professor Says

Article excerpt

Monica Greco doesn't mind when students yawn in her psychology classes at Rowan College.

"Don't be shy about it," she tells them. "I take it as a compliment. It means at least you're trying to stay awake."

Greco is an authority on the subject. Along with Temple University psychologist Roy Baenninger, she has put in years studying yawning. They've studied fish, fowl, reptiles, mammals and the college undergrad.

They found out that giraffes never yawn. "I watched them" at the Philadelphia Zoo, Greco explains. "For about a year. No kidding."

And they have managed to improve science's understanding of yawns. "It seems to be a method of self-arousal," says Baenninger.

His main area of research is aggressive behavior, but he grew intrigued by yawning when he noticed that Siamese fighting fish, which are especially feisty animals, seemed to do it a lot.

"It turns out that predators yawn a lot more than herbivores," Baenninger explains. "Herbivores just graze. They lead placid, dull lives. Their feeding is more or less constant and pretty unexciting. Predators, on the other hand, have long, quiet periods punctuated by active, exciting periods of the hunt and kill."

Baenninger and Greco, who wrote both her master's thesis and doctoral dissertation on yawning, theorize that yawning is a way of keeping all of us predators alert - "especially when things are dull but it's dangerous or inadvisable to fall asleep . . . like driving down the interstate at night, or, say, Economics 101."

Yawning is also a way for animals in a group to warn one another not to fall asleep. Baenninger says that in packs of chimpanzees, they will take turns yawning in situations where nothing much is going on, but where it is not safe to fall asleep.

Whatever the root cause, yawning is definitely contagious.

"It's so suggestible that I found research subjects started to yawn whenever I began talking to them about it," says Greco.

Baenninger says he believes yawning may be triggered when a chemical called dopamine falls below acceptable levels in the brain. Dopamine facilitates transmission of electrical impulses across the gaps (synapses) between brain cells (neurons). …