It’s a perfect spring day, and in the midst of a park full of picnic-goers and dogs playing fetch, a boy waves a yellow balloon in the air. From one corner of the park, a dad playing with his 2-year-old daughter draws her attention to the action. “I see a boy, and a balloon,” he says. “I see waving.” In another section of the park, a different dad spots the same boy with the balloon and turns to his 2-year-old daughter. “A boy is waving a balloon,” he explains, pointing to the scene. If this is the first time that either of the toddlers has ever heard the verb “waving” before, is one of them more likely to learn it than the other? A study recently conducted by Northwestern post-doctoral fellow Sudha Arunachalam (now an assistant professor at Boston University) and Professor Sandra Waxman at the Project on Child Development asks which of these ways of introducing novel verbs is most helpful to toddlers.
Though both dads have used the same words to describe the situation, the first has used what we call “sparse syntax,” meaning that the new verb isn’t embedded in a syntactically informative sentence. In contrast, the second father has used “rich syntax” to introduce the new verb. We wondered, are toddlers more likely to remember and apply the new words that they hear embedded in a syntactically rich sentence, or is the rich syntax unnecessary, perhaps even serving as a distraction that obscures the meaning of the new verb?
The 2-year-olds in our study participated in six verb-learning trials, each featuring a different “novel” verb (we use made-up verbs to ensure that the toddlers are not familiar with them). The Sparse Syntax group of toddlers heard sentences such as, “Let’s see a boy and a balloon. Let’s see pilking!” In contrast, the Rich Syntax group heard sentences such as, “A boy is gonna pilk a balloon! Let’s see!” Then, they both watched a short video clip of a boy waving a balloon. Afterwards, the toddlers were shown two different pictures, one with the same object, but a different action being performed on it (e.g., tapping the balloon), and one with the target action being performed on a new object (e.g., waving a rake). They were asked to point to “pilking.”
Although both conditions provided the toddlers with all of the semantically relevant information to understand the scene, we hypothesized that the children also given rich syntactic information would be more successful at learning the new verbs. Indeed, this was the case! The toddlers provided with Rich Syntax were much more likely to point to the Familiar Action scene than their counterparts in the Sparse Syntax group. The results provided us with two very meaningful insights: the first was that by age 2, toddlers have the remarkable ability to successfully learn new verbs and apply them to new objects and situations, even when provided with very little exposure. It also tells us, however, that toddlers need syntactically rich frames in order to more successfully do so.