Finding the brain’s common language
By Erin Wayman
Erich Jarvis dreams of creating a talking chimpanzee. If his theories on language are right, that just might happen one day.
Jarvis says that the ability to imitate sounds, not higher intelligence, is the key to language. Most animals are born already knowing the calls they’ll croon, but human babies learn words by mimicking how others talk. “I argue it’s what makes spoken language unique,” says Jarvis, a neurobiologist at Duke University Medical Center.
That realization came from an unlikely place: bird brains. Jarvis has spent more than a decade studying the brain circuitry of songbirds, parrots and hummingbirds, which are among the few critters that imitate and learn new vocalizations, a skill called vocal learning. Although humans and birds split evolutionarily from one another more than 300 million years ago, Jarvis and his colleagues have discovered that the brain circuitry for speech and birdsong is remarkably similar.
Humans and vocal-learning birds have networks of neurons that connect analogous brain regions. One of these connections hooks up a brain area related to speaking and singing to neurons in the brain stem that control the muscles of the voice box (called the larynx in humans). Animals incapable of vocal learning don’t have such connections.