How do you respond to a babbling baby? Researchers at Cornell University say a timely response to the babbling is needed to help the baby learn. Observing babies between seven and eight months old, the team used humans the baby didn’t know or remote controlled cars that would respond to the babbling by approaching the baby and making a vowel sound. The babies quickly learned to expect the response and if it didn’t occur within two minutes, their babbling got louder and more directed. The study, in the journal Infancy, offers insights into how babies of those ages learn even before they know words. Authors say babies are learning machines and its up to adults to respond in ways that facilitate that learning.