Psychologists at the University of Chicago say one explanation for why children from poorer families have smaller vocabularies is that their parents communicate with them using a narrow range of gestures.
The use of gestures, such as pointing, has been recognised as an important aspect of child development for some time. For example, the amount a child gestures at a young age predicts her later vocabulary size.
In this study, Meredith Rowe and Susan Goldin-Meadow observed 50 families from a range of socioeconomic backgrounds in the Chicago area. They first measured the variety of gestures and speech used by parents and their children during a 90-minute session when the children were 14 months old, and then they measured the children's vocabulary when they were aged 54 months.
Rowe and Goldin-Meadow found that parents and children from poorer backgrounds (i.e. of low socioeconomic status) used a narrower range of gestures when they interacted with each other compared with parents and children from more affluent backgrounds. This link between socioeconomic status and child gesturing disappeared when parental gesturing was controlled for statistically, thus suggesting, but by no means proving, that parental gesturing could be playing a causal role.
Next, Rowe and Goldin-Meadow found a link between family socioeconomic background and children's vocabulary at 54 months - an association which was weakened when the children's range of gesturing at 14 months was taken into account. In other words, at least part of the reason children from poorer backgrounds have smaller vocabularies seems to be because they use a narrower range of gestures when they're aged 14 months. Combining this observation with the earlier finding about the role of parental gesturing, implies but by no means proves, that one reason children from poor backgrounds develop smaller vocabularies is because their parents gestured to them less when they were younger.
"Given our findings, it seems fruitful for future research to explore whether parents and children can be encouraged to increase the rate at which they spontaneously gesture when they speak," the researchers said.
Link to earlier related Digest post.
Meredith L. Rowe, Susan Goldin-Meadow (2009). Differences in Early Gesture Explain SES Disparities in Child Vocabulary Size at School Entry. Science, 323, 951 - 953.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.