Animal acoustic communication
Our research aims to elucidate the mechanisms and evolution of animal acoustic communication through a comparative and evolutionary lens, using a naturalistic approach that combines laboratory and field observations and experiments. We employ various methods to investigate the relationship between anatomy and signal production (e.g., CT scans, numerical modeling of vocalizations), signal processing (e.g., neural networks, algorithm design for sound synthesis), statistics (e.g., quantifying information encoded in acoustic signals), and playback experiments using both natural and synthetic signals. For example, our work covers acoustic communication networks in ultrasound-producing animals (rodents), the coding and decoding of social and individual information in large mammals (elk/wapiti, hippos, elephant seals, and non-human primates), and the biogeography of bird song. Our conceptual framework is rooted in Shannon’s Mathematical Theory of Communication, and we strive to understand communication processes in their entirety: the mechanisms of sound signal production and information coding, the propagation of sound through the environment (including the resulting loss of information), and signal reception and decoding. We combine an experimental approach grounded in ethology—closely reflecting the natural experiences of animals—with big data analysis to achieve a global understanding of communication strategies and information coding-decoding in acoustic signals.
Human non-verbal communication
Human cries, laughter, screams and grunts remain poorly understood. By combining state-of-the-art technologies for voice synthesis, psychoacoustic experiments and neurophysiological investigations, we investigate the production and perception processes of these vocalisations, and the factors modulating them, thus reinstating their forgotten importance in our social interactions and gaining novel insight into the origins of human vocal communication, including speech. We explore the acoustic properties and communicative functions of various vocalizations like pain screams, agression roars, and pleasure moans, differentiating between genuine and acted expressions. We analyze recordings from diverse sources, including real-life contexts (sometimes in combination with other sensory modalities, as olfaction during a meal), simulated scenarios, and online media, and use innovative acoustic synthesis techniques. We examine how sensory experience, cultural factors, and early childhood development influence the production and perception of these nonverbal vocalizations. By studying both typical and sensory-impaired individuals, as well as a remote tribes in Africa or Papua New Guinea, we seek to uncover universal and culturally specific aspects of human vocal communication. We also use bioacoustics to address biomedical questions. Our research on babies' cries contributes to a better understanding of parent-child interactions. By making sounds visible, our work on sensory substitution opens up totally new and powerful application possibilities for deaf and hearing-impaired people, such as visual baby monitors to empower deaf parents to interpret the cries of their babies, and visual tools for speech therapy or auditory rehabilitation in cochlear implant users.
In the context of global change, where natural environments are undergoing significant and abrupt variations in their composition and functioning, the development of efficient, non-invasive and inexpensive monitoring methods is an essential challenge. We deploy stand-alone acoustic recorders in various terrestrial and aquatic ecosystems, from African savannas to French temperate forests, via peri-alpine lakes and coral reefs, to capture long-term dynamics in diversity. We quantify the respective contribution of different sound sources to soundscapes and investigate how they evolve as restoration programs are implemented. A significant part of our research is also devoted to the development of advanced machine learning approaches to analyze the colossal amounts of acoustic data needed to monitor biodiversity. Besides passive acoustics, we also design acoustic-based tools to help species management. We combine bioacoustics and ethology to keep animals away from human activities that pose a risk, or to help capture species that are a threat to local biodiversity, such as invasive alien species. Overall, our results argue in favor of integrating acoustics, passive or active, into the toolbox of ecosystem managers. They also support sustainable management strategies to restore the human-nature connection.
Effects of anthropogenic noise
Anthropogenic noise is the most widespread and immediate symptom of human activities, and finding a place on Earth that would be free of human-made sounds is virtually impossible today. Most, not to say all, animals, can perceive sounds are could therefore be disturbed by anthropogenic noise. While the effects on the behavior and physiology of individuals are well documented, the long-term consequences and those at the population and community levels remain unknown. We perform playback experiments, both in the lab and the field, with a focus on freshwater ecosystems, which remain understudied compared to terrestrial and marine ecosystems while experiencing much faster rates of biodiversity decline. Our experimental setups are built on the basis of a robust ecological framework, with a strong grounding in predation theory. Extrapolating results is one of the central themes of our research projects. Can we predict alterations in populations and community-based ecological processes from subtle deviations in behavior and physiology observed at the level of individuals? Can we use laboratory-raised animals to understand how wild populations react to noise pollution? Human-generated noise poses a threat not only to wild species, but also to captive animals raised in facilities for experimental purposes, and which can suffer from suboptimal acoustic conditions. By addressing this issue, we hope to provide solutions to improve animal welfare.