In Neil Postman’s The Disappearance of Childhood (1982) he makes the argument that what we define as “childhood” is largely a social construction, a construction made possible by the printing press and the subsequent rise in literacy levels in western society. The general idea is as follows....
Prior to this development, in medieval times children and adults inhabited the same “social and intellectual world” where both carried out identical labour tasks and pastimes like gambling were seen as normal childhood activities. As the special classes of the time had access to knowledge, this meant that the vast majority outside of that had roughly the same intellectual capacity. For Postman, the lack of “civilised” mores that regulate our behaviour (bodily functions to personal attributes that would be frowned on in modern society etc. ) today were completely absent back in that time and “Without a well-developed idea of shame, childhood cannot exist”. In other words, any society that lacks proper education, literacy and a sense of shame will therefore lack a sense of what we believe childhood to be. This changed when the printing press allowed for adults to gain literacy and this acted as a gatekeeper to adult secrets that could only be read by the literate (i.e.. adults).. This created the social hierarchy between adult and child. The school system then became a means to prepare the child for adult literacy. With this separation came an increased focus on things like birthdays and welfare alongside literature that was aimed to promote childhood as a time of idyllic innocence.
This era of innocence reached its zenith between 1850 and 1950, for Postman this era had the perfect balance of naivety of outlook coupled with general protective attitudes in society at that time. This all changed with the introduction of television. This took away the dynamics of the adult literacy world again, making its boundaries porous enough to be navigated by children who consumed advertisements. Unlike literacy, television requires no learning, making it open to everybody to make sense of and disseminate the given narrative. Things that would have usually been consumed by children like superhero movies are now marketed at adults too, for an even more up to date example we can look at computer games following the exact same marketing strategy. The boundaries between childhood and adulthood are becoming blurred once again. Postman believes the increased amounts of anti-social behaviour, lack of respect for elders and use of curse words have been brought about by the negative influence of mass media.
If we can boil that down, it essentially means that Postman is arguing that media telecommunications have a role in shaping society.