D. E. Broadbent. Levels, hierarchies, and the locus of control. Quarterly Journal of Experimental Psychology, (29):181–201, 1977.

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This old paper describes a multi-level adaptive control mechanism of problem-solving situation. The general principle explained is that human processing of information takes place on many levels: some of these levels modify or control the operation of others.

The author describe his setup for controlling problem-solving solution, which is constituted by a simulation of bus transport in a city. The users can alter the time interval between the buses entering the city, and they can alter the amount charged for use of the city car’s park. By altering these quantities, they can affect the load on the buses, which is usually expressed in the number of people carried per hundrerd buses. They can also affect the number of empty spaces remaining in the car parks. Before experience of the situation, and again afterwards, the users are questioned on the effect of their interventions on the system. Despite the satisfactory performance atteined in the task, their ability to answer questions about what they did on the system was poor.

Then, the author describes different control mechanisms, showing that the structure that could explain the obtained results of the task is an adaptive controller structure. The key point of the paper is that the transfer of controlshould include the possibility that one section of the program/structure can alter other sections program/structure.