The Gutenberg Galaxy 1-90

      This brings up a quick point of how standardization of printing changed human thinking and writing. As the act writing become more accepted, writers/orators could turn away from the interpersonal relations and concentrate on the intrapersonal.  This simple act of focuses within the internal could have helped ignite the countries interest in fields such as psychology and cognitive development. Writing (post-classic literature) gave the writers the freedom to explore previous untouched areas of the conscious and subconscious, without worrying about the reaction of a specific audience. Writers during this period wrote to explore, pursue, and evaluate not only the potential of the medium but also human thought.  

http://jerz.setonhill.edu/EL336/2008/mcluhan_190.php