Spreadsheet analysis of a hierarchical control system model of behavior

The behavior of a hierarchy of control systems can be simulated with an electronic-spreadsheet. Each control system is a column of three cells representing the reference signal, perceptual signal, and output variable of the system. All of the control systems are closed-loop, the input to each system being a function of its output. The circular references in the spreadsheet are resolved through iterative recalculation. When the parameters of each control system (amplification and slowing factors) are set to appropriate values, all control systems in the hierarchy continue to match perceptual signals with reference signals. A three-level hierarchy with four systems at each level is simulated in the spreadsheet. The spreadsheet model makes it possible to observe the dynamic behavior of the control systems as they correct for the effects of environmental disturbance and changes in higher order reference signals. It is possible to “reorganize” the system by changing the perceptions controlled by systems at different levels of the hierarchy. The user can also test to determine the variables being controlled by the system.