Collective decision-making in social animal groups often emerges from simple local interactions and can give rise to abrupt transitions between distinct behavioral states. In this talk, we explore how coordination, information transfer, and environmental constraints shape these transitions in animal collectives. Using controlled experimental systems combined with quantitative analysis, we investigate how groups integrate sensory information and social interactions to reach consensus and coordinate movement, particularly in constrained or heterogeneous environments.

Our results highlight the key role of group interactions and sensorial cues in driving collective outcomes, revealing how small changes in environmental conditions or information accessibility can trigger qualitative shifts in group behavior, akin to phase transitions in physical systems. We further discuss how the interplay between individual behavior, group cohesion, and environmental structure governs the efficiency of collective decisions and navigation. These findings contribute to a broader understanding of active and living matter, bridging physics and biology, and provide new perspectives on how collective intelligence emerges in natural systems.