In the first few years of their lives, children develop at a fantastic speed and acquire rich knowledge as well as a variety of abilities – they learn, for example, to communicate effectively, to understand and engage in social interactions, to categorize the things surrounding them, or to use simple tools. We would like to find out more about this fascinating and complex process through our research, our primary goal is extending knowledge. In many cases the information acquired this way can also be useful in practice, for parents or professionals who work with children (e.g. in education or in the clinical field). In addition, it can also facilitate research in partner fields, such as anthropology, linguistics, ethology, philosophy, and neuroscience.