Speaker
Description
Among primates, callitrichid monkeys are the only cooperative breeders besides humans and are characterized by high social tolerance and extensive vocal behavior. In a previous study, we measured marmoset vocal activity across different contexts and observed some predictable status differences in contact and warning calls. However, results were less clear for call types used to share information about food or potential threats. Here, we test the hypothesis that an individual’s tendency to share information with another may depend on the quality of their relationship and therefore examined the connection between volubility and sociality as well as individual features such as hormonal profiles.
We recorded all possible dyads from 14 marmoset groups in an experimental setup designed to induce information asymmetry, where only one member of a dyad had access to food or an ambiguous stimulus, while the other was prevented from seeing what was happening, and both could only interact vocally. We also gathered independent data on social tolerance (co-feeding experiments) for each group and dyad in parallel to the experiment, along with hair samples to analyze long-term hormone levels (cortisol and testosterone).
We expected that dyads characterized by higher social tolerance would share more information and engage in more vocal exchanges. Moreover, individuals with higher base cortisol could be more reactive and produce more distress vocalizations when triggered by potential danger.
Our results will reveal if marmosets base their decision to share information with group members on social bond strength, and how this is embedded in their hormonal background.
