This study will introduce some of the fundamentals and rationale for the Psychology of Media Education based on Developmental Psychology. It is an important area of study of a modern teacher profession and teacher education and a new field of multi-, inter- and trans-disciplinary knowledge and research. We argue that without a doubt the different symbol- or media environments are influencing young children, adolescents and adults in their everyday life. We could even speak about media(ted) cultures based on media environments including traditional printed media, audiovisual media, interactive computer media and the rapidly growing phenomena like mobile communication, CMMC (computer mediated multimedia communications), web-communities, networked games and virtual reality communities. The significance and influence of media environments need to be publicly recognised in educational contexts of children and adolescents too.