CHICAGO--Point your fingers, wave bye-bye--maybe even flap your arms like a bird: it could boost your young child's vocabulary in preparation for school, researchers report at the 2009 AAAS Annual Meeting.

Children who convey more meanings through these simple, spontaneous gestures at 14 months have much larger vocabularies by age four than children who don't express as many meanings through gesture, said Meredith Rowe and Susan Goldin-Meadow, researchers at the University of Chicago.

What's more, children from wealthier, more educated families tend to gesture more distinct meanings than children from low-income, less educated families, Rowe and Goldin-Meadow report in the 13 February issue of the journal Science. It's parents that seem to be the key factor, the researchers found: the more parents use these gestures, the more their children adopt them in their own communication.

The findings could partially explain why children from higher socioeconomic status families tend to come to school armed with a better vocabulary than their lower-income peers. "Vocabulary is a key predictor of school success and is a primary reason why children from low-income families enter school at a greater risk of failure than their peers from advantaged families," said Goldin-Meadow.

Of course, gesturing is just one way that parents contribute to their children's vocabulary, the researchers acknowledged. Other studies show that parents who speak with a larger vocabulary raise children with a larger spoken vocabulary. Goldin-Meadow and Rowe say their study accounts for that effect, and shows gesture's influence on vocabulary "above and beyond" speaking.

It's still unclear why gesturing might "facilitate the development of vocabulary," Rowe said at an Annual Meeting news briefing. But the researchers point out that parents are often quick to supply a verbal answer to a child's questioning finger, saying things like "yes, that's a cup!" or "No, don't touch the sharp needle!"

Or it may be that the physical act of gesturing "actually may change your mind," Goldin-Meadow said. In her ongoing studies of older children, which she will present on Sunday at an Annual Meeting symposium, Goldin-Meadow found that students encouraged to gesture while solving math problems did better on tests than those who kept firmly kept their hands to themselves.