The researchers could not say with certainty why the differences emerged with reading and writing but not math, but they could guess.
"These children probably don't engage in a lot of math-based after-school activities," Weis said. "You can imagine a little boy going home and reading a story or having his parents read to him, but you can't really imagine a first-grade boy wanting to do math problems for fun. There's not a whole lot of displacement there."
The fact that video games can cut into study time seems to be an obvious explanation, but there could be others, the researchers said.
"Video games could affect a child's brain, particularly executive functioning, and it could compromise his or her ability to do well in certain academic activities," Weis said. In children, executive functioning refers to such things as their ability to manage time and keep track of more than one thing at once.
In any event, Delamater said, "parents should be limiting the exposure these kids have to video games."
Or at least calling for balance, Weis noted.
"I tell students that we have to follow Aristotle's golden mean and that is to strive for moderation in all the things that we do," he said. "That means moderation in after-school academic activities like homework and also moderation in video-game playing and other recreational activities."
The Kaiser Family Foundation has more on video-game playing.
SOURCES: Robert Weis, Ph.D., associate professor, psychology, Denison University, Granville, Ohio; Alan Delamater, Ph.D., director, clinical psychology, Mailman Center for Child Development, University of Miami Miller School of Medicine, Miami; April 2010 Psychological Science
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