Israel ISF-DFG: The effect of social interactions on (dis)honest communication

• Applicant: Dr.-Ing. Tomas Arias Vergara
• Subject Area: Sensory and Behavioural Biology ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 561160625

Animals make decisions based on cues that they receive from conspecifics. Acoustic cues, encoded in vocal frequencies, tempo, and syntax, convey honest information on, for example, the age and social status of the singer. Yet numerous studies in birds, anurans, and humans show that in social interactions (e.g., duets and counter-singing), acoustic features shift, compared to solo singing. This raises intriguing questions: How do social interactions affect honesty? Do they prompt a dishonest display of traits or a correction to display honest ones? Here, we propose to elucidate whether and how these social-context-affected changes reflect the honest depiction of individual traits, a topic that remains underexplored. For over 25 years, we have been studying the complex songs of male wild rock hyraxes (Procavia capensis), focusing on solo songs (performed spontaneously) and counter-singing (e.g. induced by other male songs). Male hyrax songs include a challenging sound called the "snort," a harsh sound developed with age, which varies with weight, social status, and hormone levels. While prior research shows that snorts differ between solo and counter-singing, their honesty in reflecting the singer’s traits wasn't assessed. This study aims to evaluate whether counter-singing represents the responder's traits than solo singing and to understand how social factors like weight and status affect these acoustic differences. To this end, we will adapt/implement novel methods originally designed for monitoring orcas (Orcinus orca), including denoising, segmentation, encoding, and generating artificial calls. Hyrax songs will be analyzed using deep learning methods to cluster the songs; thus, enabling automatic identification of distinct singers’ vocalizations (including ones we fail to observe in the field). Furthermore, new songs will be synthesized using generative AI to examine counter-singing behavior in the field. The effect of social context on the honest transmission of individual traits will be measured using acoustic analysis by contrasting the responses with the singer's solo songs. We hypothesize that vocal behavior will change according to both the initiating singer’s (or playback’s) and responder’s individual characteristics. This study is expected to elucidate whether social constraints generate honesty and expand our understanding of the contribution of sociality to the evolution of vocal communication in nature.

• DFG Programme: Research Grants
• International Connection: Israel
• Partner Organisation: The Israel Science Foundation
• Cooperation Partner: Professorin Dr. Lee Koren, Ph.D.