ABSTRACT
A major step in the development of human culture and society has to do with the invention of a system for the external representation of the sounds of human language. As a cognitive tool the art of reading and writing has had a profound impact on society and human cognitive functioning. It can even be claimed that the evolution of mankind from “barbarism” to “civilization” was the result of literacy. Written language has obviously the character of an external memory system where its spatial lay-out and its permanence permit inspection and repeated controls of the stream of thoughts, thereby considerably reducing the working load of the human memory. As with all revolutionary inventions, however, written language has also had unintended side effects.
