Much of what we will be as adults depends on the first years of life, on what we simply observe happening around us and not only on what we are taught explicitly. This also applies to the development of the visual system. This is the conclusion reached by two SISSA neuroscientists, who, for the first time, have experimentally shown the importance of passive visual experience for the maturation and the proper functioning of some key neurons involved in the process of vision. The research, published in Science Advances, is a fundamental step towards understanding learning mechanisms during development. It also has potential clinical implications, for the study of new visual rehabilitation therapies, and technological implications, where it could lead to an improvement of the learning algorithms employed by artificial vision systems.