Note: This study was part of a larger longitudinal study, information available here.
Wouldn’t it be fantastic if we could screen infants at 8 months and predict later development? This study looked at gesture and object use at 8 months, then followed up at ages 1;0 and 2;0 to determine whether later vocabulary can be predicted by early gesture and object use. The authors mailed out questionnaire packages to 1,477 families when their children were ages 0;8, 1;0, and 2;0. The Macarthur-Bates Communicative Development Inventories (CDI) were included in the packet, the CDI Words and Gestures (CDI:W&G) was completed for the first two data collections, and the CDI Words and Sentences (CDI:W&S) was completed at the 2-year mark.
In addition to measuring gestures to predict vocabulary use, the authors also examined the effects of SES and gender on vocabulary. Here’s what they found:
- Gestures at 0;8 didn’t predict vocabulary (at 2;0) all that well. But gestures at 1;0 year did. Also, gestures predicted 2;0 vocabulary comprehension better than production.
- Girls produced more words than boys at 1;0 and 2;0, but there were no differences between boys and girls in comprehension
- Children in the two higher SES groups (there were 5 groups total) reportedly understood fewer words than the children in the lower SES groups. And children in the second lowest SES group were reported to produce more words than children in the higher SES groups
Remember that these fun facts were all based on the CDI, which relies on parent report. So how can we use this information? The authors suggest that parent estimation of their children’s skills may differ by SES; that is, families in lower SES backgrounds may overestimate their children’s abilities, or families from higher SES backgrounds may underestimate their children’s knowledge. This is something to keep in mind when many of our assessments in EI are based, in some capacity, on parent report.
Bavin, E. L., Prior, M., Reilly, S., Bretherton, L., Williams, J., Eadie, P., ... & Ukoumunne, O. C. (2008). The early language in Victoria study: Predicting vocabulary at age one and two years from gesture and object use. Journal of Child Language, 35(3), 687-701.