[3] After completing his MA, Blackwell started working at the New Zealand software company Progeni Systems Limited.
Blackwell's research interest is in the field of constructing and applying "models of human behaviour when interacting with technology."
In its introduction he described that diagrams have an important role in problem representation: One of the central insights offered to cognitive science by artificial intelligence research is the importance of problem representation when creating effective implementations of intelligent behaviour.
Diagrams are an interesting artefact for this reason — their purpose is purely to modify the representation of problem situations.
One of the reasons is its status between linguistics and perceptual theory: Diagrams are not easily amenable to the methods that have been used to investigate other varieties of human markings.