ESI Lecture by Steffen Hage

The Neurobiology of Primate Vocal Communication

Monkey vocalizations have been assumed to be largely innate, highly affective, and stereotyped for over 50 years. Recently, this perception has dramatically changed. Current studies including our own have revealed distinct learning mechanisms during vocal development and vocal flexibility allowing monkeys to cognitively control when, where, and what to vocalize. I will give an overview on our recent studies on macaque and marmoset monkeys. I will start with our studies investigating the neural network underlying volitional control of vocal output in macaque monkeys. Then, I will present new data that are indicating that vocalizations of marmoset monkeys do not consist of one discrete call pattern but are built out of many sequentially uttered units, like human speech. Furthermore, I will give insights into recent studies that indicate a potential role of auditory feedback on vocal development in marmoset monkeys. Finally, I will show data indicating that marmosets, similarly as macaque monkeys, are able to control their vocal output in a goal-directed way to perform a specific task successfully. Taken together, our results suggest monkeys as a suitable model system to investigate critical preadaptations of human speech, which are already present in our last common ancestor and which were crucial for the evolution of human speech in the primate lineage.