My research focuses the behavioral and cognitive mechanisms involved in the phenomena of collective intelligence observed in a wide range of animal societies, including humans. This work which tightly combines experiments and modeling is highly interdisciplinary. It falls within the broader framework of quantitative ethology and computational biology. The objective is to understand the processes that are used by groups living animals within vertebrates (such as schools of fish, herds of ungulates, and human crowds) and invertebrates (social arthropods) to make collective decisions, coordinate their activities to build complex architectures, or perform sophisticated movement maneuvers. These collective behaviors result from interactions among individuals, during which many types of information (chemical, tactile, vibrational, visual) are exchanged. To analyze these behaviors, I developed a methodology that characterizes and quantifies both individual and collective behaviors separately and subsequently connects the two scales of phenomena through mathematical models.