Alissa Ferry, a postdoctoral fellow in the Language, Cognition and Development Lab at the Scuola Internationale Superiore di Studi Avanzati in Trieste, Italy, with colleagues from Northwestern University are the first to document that human babies can learn from non-human primate vocalizations just like human babies learn from human speech in the Sept. 3, 2013, edition of the journal Proceedings of the National Academy of Sciences.
Human children that are three to four months of age cannot speak a language but research has documented that children of this age begin to form the ability to categorize objects, persons, and information from hearing human speech.
The researchers proposed a test of the response of human children to non-human primate vocalizations.
Human children were exposed to the taped vocalizations of lemurs. The children were three to four months of age.
The children demonstrated the same category formation response to lemur vocalizations that they did to human speech. Tapes of the lemur vocalizations played backwards did not produce the same mental development responses. Tapes of human speech played backward did not elicit the learning response either.
The ability to respond to lemur speech disappeared at age six months in the test subject children.
The researchers propose that the learning response in babies may be evolutionary and that language and learning have a non-human origin based on the experimental results.