This report describes research exploring the relationship between structure and cognitive
complexity in Air Traffic Control (ATC). Current work on structure and cognitive
processes in ATC is reviewed leading to an ATC process model.
Based on observations of the performance of the ATC system it appears that air
traffic controllers have the ability to manipulate structure and structure-based abstractions
in order to regulate the complexity of an ATC situation. The management of
complexity has been integrated into the Controller Process Model through a Complexity
Manager. It is hypothesized that the Complexity Manager operates by commanding
switches between operating modes.
In order to explore whether these operating modes can be observed in a simple
ATC task, an experiment was designed. Participants were given scenarios with varying
traffic levels. Their commands and their performance have been collected and analyzed.
The experimental results show participants appeared to use each of the hypothesized
operating modes. The use of the structure in each mode was also as expected
