The manual gestures that hearing children produce when explaining their answers to math problems predict whether they will profit from instruction in those problems. We ask here whether gesture plays a similar role in deaf children, whose primary communication system is in the manual modality. Forty ASL-signing deaf children explained their…

The types of gesture+speech combinations children produce during the early stages of language development change over time. This change, in turn, predicts the onset of two-word speech and thus might reflect a cognitive transition that the child is undergoing. An alternative, however, is that the change merely reflects changes in the types of…

When a behavior disappears and then resurfaces, developmental psychologists typically look more closely at the behavior to figure out what is different before and after--that is, they increase the grain with an eye toward discovering how the system that generates that behavior has changed. But what ought to count as a U-shaped phenomenon? How…