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Child’s Play (video)
November 08, 2001

Also on ScienCentral News

Running and Learning (video) - Researchers say that burning energy may help kids learn better. (11/1/01)

Read My Eyes - Scientists using new technology to study infants’ eye movements say they can reveal what babies know and how they learn. (2/6/01)

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Elsewhere on the web

San Diego Zoo’s Baby Animals page

"The State of Children’s Play" - white paper from the Academy of Leisure Sciences

"The Power of Play" - Toy Industry survey

Dog Sports

Are the kids getting on your nerves? Maybe you shouldn’t come down too hard on their playing around.

Because as this ScienCentral News video reports, scientists studying animals have found an important reason for playful behavior.

Legitimizing Play

In order to come to the conclusion that play serves a role in brain development, researchers like John Byers, professor of zoology at the University of Idaho, began to approach the question from a physiological perspective, rather than the usual sociological one.

For one, observations and comparisons of which animals play reveals that play is associated with big brains. "Do fish play?" Byers asks. "Essentially, no. Do reptiles or amphibians play? Essentially, no. Play almost entirely occurs just in the birds and the mammals, the warm-blooded animals that have pretty big brains."

In large-brained animals, the brain continues to develop after birth. Scouring the existing literature for studies of both the rates and timing of play, and of brain development in various species, Byers found a number of species for which studies existed for both. Comparing those studies revealed a correlation between play and development in one part of the brain, the cerebellum, the hind part of the brain that controls motor skills.

"We know that there is this period of development after birth when there’s been an overproduction of connections between the cells in the cerebellum," Byers says. "During this period of development, the cells are being pruned—some connections are going away, and some connections are being maintained." This process is called "synaptogenesis." The rate of that process has an inverted U-shaped curve: It starts off small, rises to a peak, then declines. The rate of play also varies with age in an inverted curve. And, Byers found, the peaks of the two curves match. "That period of experience-dependent pruning occurs exactly when play is occurring," he says. Byers thinks play might be important in other parts of the brain as well. Synaptogenesis is also important in the cerebrum, the front part of the brain that plans and reasons.

Good supporting evidence, but not proof of cause-and-effect, says Steven Siviy, psychology professor at Gettysburg College. A true test would allow one group of, say, rat pups, to play while another group was deprived of play, then compare the amounts of synaptogenesis that occurred. That experiment hasn’t been done (or at least hasn’t been published). But Siviy’s own research shows that rats allowed to play produce proteins involved in memory and learning in all parts of the brain, while rats not allowed to play do not. Like Byers’ discovery, that is "consistent with what we would expect to see if play were changing the brain," Siviy says.

What play biologists do agree on is that play is important. Numerous studies, including Byers’ observations of pronghorn antelopes on the National Bison Range have documented that animals that do play devote a great deal of energy to it. Siviy says humans are no exception.

"The thing that strikes me," says Siviy, father of four, "is how prevalent it is, the amount of time and effort our children put into this activity. Kids would rather play than eat. They’d rather play than go to sleep. It amazes me there’s not more work done on it."

He says the work that has been done has already begun to "legitimize play."

"Parents, teachers and school administrators often get tired of kids playing," Siviy says. "There’s this conflict, they want them to have fun, but they don’t want them to have too much fun. Play is important. Play should be a part of early-childhood education, and should be incorporated into how kids learn."

by Joyce Gramza

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