Limited capabilities for condition-dependent modulation of vocal turn-taking behavior in marmoset monkeys.

Taking turns plays an important role in primate communication and involves individuals producing species-specific calls in response to conspecific vocalizations. Recent studies have revealed that marmoset monkeys are an ideal primate model system to investigate vocal turn-taking behavior and the corresponding sensory-motor interactions. However, it is largely unknown how external factors such as conspecific call latency influence this vocal behavior. Using interactive playback, we systematically answered vocalizations of monkeys with either short- or long-call response latencies. By placing marmosets in these different behavioral conditions, we demonstrate that vocal turn taking is a robust behavior with only minor condition-dependent changes that is exhibited not only in the range of species-specific call latencies of vocal partners but also in conditions well outside natural behavioral boundaries. We find that specific features of vocal performance such as call response rates and call sequences remain surprisingly stable, whereas others such as turn-taking rates and response latencies exhibit condition-dependent differences during this behavior. These condition-dependent modulations suggest that a combination of flexible and more rigid mechanisms control marmoset vocal turn-taking behavior. (PsycINFO Database Record (c) 2019 APA, all rights reserved).