Babies who use many gestures to communicate when they are 14 months-old have much larger vocabularies when they start school than those who don't, US researchers said on Thursday.

They said babies with wealthier, better-educated parents tend to gesture more and this may help explain why some children from low-income families fare less well in school.

"When children enter school, there is a large socioeconomic gap in their vocabularies," said the University of Chicago's Meredith Rowe, whose study appears in the journal Science.

Gestures could help explain the difference, Rowe told the American Association for the Advancement of Science annual meeting in Chicago.

Vocabulary is a key predictor of school success. Earlier research showed that well-off, educated parents tend to talk to their children more than their poorer, less-educated peers.

"What we are doing here is going one step earlier and asking, does this socioeconomic status relate to gesture, and can that explain some of the gap we see at school entry," Rowe said.

The researchers filmed 50 Chicago-area children and parents from diverse economic backgrounds and counted the number of gestures, such as pointing at a picture.

The team found that 14-month-olds from high-income, well-educated families used gesture to convey an average of 24 different meanings during each 90-minute session, compared with 13 meanings conveyed by children from lower-income families.

When the same children entered school at age four and a half, those from higher-income families had better vocabulary scores on standardized tests.

"At 14 months, an age when there aren't even socioeconomic differences in their talk yet, we see there are differences in their gestures," Rowe said.

The videos revealed that parents from wealthier families gestured more with their children than the other parents.

Rowe said the findings suggest that gestures can at least partly explain vocabulary differences between the groups, and may prove useful as the basis for interventions.

"Can we manipulate how much parents and children gesture, and if so, will it increase their vocabulary?" Rowe said.

美國研究人員于上周四稱，如果寶寶在14個月大時會用很多動作進行交流，那么到了上學的時候他們掌握的詞匯會比不喜歡用動作交流的寶寶多。

研究人員說，家庭較富裕、父母受教育水平較高的寶寶更愛用動作進行交流，這或許可以解釋為什么有些低收入家庭的孩子學習成績不太理想。

芝加哥大學的梅里蒂斯•羅伊說：“孩子在剛上學時，他們在詞匯方面存在一個很大的社會經濟差距。”該研究結果在《科學》期刊上發表。

羅伊在芝加哥召開的“美國科學進步協會”的年會上說，動作可以解釋這一差別。

詞匯是決定孩子學習成績好壞的一個關鍵因素。此前的研究發現，家庭收入和受教育水平較高的家長比收入和受教育水平較低的家長更經常與孩子說話。

羅伊說：“我們需要解決的問題就是，再往前追問一下：這種社會經濟地位與孩子在日常交流中所做動作的多少是否有關，是否能解釋孩子在剛上學時存在的一些差距？”

研究人員對芝加哥地區50對經濟背景各不相同的父母和孩子進行了拍攝，并統計了他們所做動作的數量，比如指著一張畫。

研究小組發現，在每個90分鐘的時間段內，來自高收入和高文化水平家庭的14個月大的孩子用動作表達了24種不同的意思，而低收入家庭的孩子只用動作表達了13種意思。

當這些孩子到了四歲半開始上學時，高收入家庭的孩子在標準化考試中的詞匯得分較高。

羅伊說：“在14個月大時，孩子在語言上還不存在社會經濟的差別，但我們看到他們在動作上已經有了差別。”

從所拍攝的視頻可以看出，高收入家庭的家長比其他家長更傾向于用動作與孩子交流。

羅伊說，研究結果表明，動作至少可以解釋為什么不同家庭背景的孩子在詞匯掌握上存在差別，而且或許能為社會干預提供基礎。

羅伊說：“我們能控制父母和孩子在日常交流中使用多少動作嗎？如果可以，那么這能增加孩子的詞匯量嗎？”