Can 19-month-olds process wh-questions incrementally?

When adults hear a wh-question with a fronted object, like What is she wiping with the cloth?, they interpret what as the direct object of the verb wipe rapidly, as the sentence is unfolding in real-time. In our prior work, we found that 18-month-olds are able to represent the structure of these questions. Here, we asked whether 19-month-olds can process them in an incremental manner, similar to adults.

We tested 19-month-olds on a word-learning task. One group of infants heard simple declarative sentences with a novel noun, such as She’s wiping with the tig. Previous work finds that 19-month-olds tend to mis-process this sentence: because they know that wipe requires a direct object, they predict an upcoming object for the verb, and erroneously interpret the tig as the thing being wiped rather than the thing being used for wiping. We asked whether infants would make the same mistake if they hear a wh-question, such as What is she wiping with the tig? We played these sentences alongside a video in which a girl is using a cloth to wipe a camera, and then asked them to find the “tig” while looking at images of the camera and the cloth. We found that 19-month-olds looked erroneously at the camera when they heard She’s wiping with the tig, but successfully looked more towards the cloth when they heard What is she wiping with the tig? This tells us that they were able to use their knowledge of the structure of this wh-question to process this sentence rapidly. Because they interpreted what as the direct object of the verb in real-time, they were able to avoid the processing mistake that would otherwise lead them to mis-interpret the tig.