Tiny tots who convey gestures more meaningfully at 14 months have larger vocabularies at 54 months and are also better prepared for school.
Differences particularly favoured children from higher-income families with well-educated parents and may explain disadvantages children from low-income families face upon entering school, said Susan-Goldin Meadow, who co-authored the study with psychologist Meredith Rowe, both of the University of Chicago.
"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, psychology professor and leading expert on gesture.
Although scholars have realised that families of higher income and education levels talk more with their children and speak to them in complex sentences, the new study is the first to connect gesture, vocabulary and school preparedness.
Goldin-Meadow and Rowe, postdoctoral scholar, studied 50 Chicago-area families from diverse economic backgrounds. They recorded video of children and primary caregivers for 90-minute sessions during ordinary activities at home. <b1>
The researchers found that differences in gesture appeared early among children; moreover, differences in child gesture could be traced to differences in parent gesture.
Fourteen-month-old children from high-income, well-educated families used gesture to convey an average of 24 different meanings during the 90-minute session, while children from lower-income families conveyed only 13.
Once in school, students from higher-income families had a comprehension vocabulary of 117 (as measured by a standardised test), compared to 93 for children from lower-income families, said a Chicago release.
Some of the robust differences in child vocabulary development at 54 months are likely to come from parents in higher-income groups using gesture to communicate more different meanings when their children were 14 months, the paper said.
These findings were published in Science on Friday.