Monkey studies reveal possible origin of human speech

July 23, 2018, Rockefeller University

Most animals, including our primate cousins, communicate: they gesture, grimace, grunt, and sing. As a rule, however, they do not speak. So how, exactly, did humans acquire their unique talent for verbal discourse? And how do our brains manage this complex bit of communicative magic?

Scientists in the lab of Winrich Freiwald have shed new light on the underpinnings of human speech by identifying neural circuitry in the brains of monkeys that could represent a common evolutionary origin for social communication. As reported in the journal Neuron, these circuits are involved in face recognition, facial expression, and emotion. And they may very well have given rise to our singular capacity for speech.

Body Language

Working with rhesus macaque monkeys, Freiwald had previously identified neural networks responsible for recognizing faces—networks that closely resemble ones found in the human brain.

Other researchers, meanwhile, had suggested that particular areas of the brain might be responsible for producing facial expressions. But no one had imaged these facial motor regions while they were active, much less when they were being used for communication. Nor did scientists understand how these networks might interact with each other and with areas of the brain that handle emotion, another integral component of social interaction.

Continued