Reading some of the recent papers by Robert E. Horn and thought I would check out
Engelbart: Augmenting Human Intellect (1962) which he mentions quite a lot. This particular section starts with an "historical progression in the development of our intellectual capabilities: Concept Manipulation, Symbol Manipulation and Manual, External, Symbol Manipulation."
This is very timely as I am currently considering the whole notion of connected (in that they are linked) and individual (both personal or collaborative) representations of cmc-spaces.

Also came across the Transformative Approaches Project, part four looks at visualisation and comprehension. Visualization: Augmenting human intellect on the Union of International Associations site?