This website serves as a repository for computer programs that were developed to highlight various aspects of Perceptual Control Theory (PCT), a theory of human and animal behavior developed by William T. Powers.  According to PCT (and the title of Bill's seminal 1973 book), behavior is the control of perception. To control a perception is to take actions that tend to bring the perception toward a given state (reference value) and keep it there by opposing the effects of any disturbances to that perception, as in steering a car so as to keep it on the road and heading where we want it to go.

In 2009, Bill published his final book on perceptual control theory, Living Control Systems III: The Fact of Control, available from Benchmark Publications. I had the privilege of working with Bill to develop a series of thirteen demonstration programs that are included with the book and serve to illustrate the principles that Bill discusses.  Zipped files containing the source code for these Delphi programs and the executable programs themselves are available for download on this site.

Other files posted to this site include a version of Power's "Little Man" simulation of visual and kinesthetic perceptual control of a 3 df arm, a simulation based on an alternative to Hill's muscle model developed by Powers and Richard Kennaway, a version of the "level 1" muscle length/force controller described in Powers (1973), a simulation of the same based on Anatol Feldman's "equilibrium point" (EP) model, a version of the LCS III "TrackAnalyze" program modified to use joystick input, and miscellaneous others.

All the programs available here were written in the Delphi programming language and run in Windows.  Copyright permission is granted for use in education and research purposes only.  

Bruce B. Abbott
Subpages (2): LCS III Files Other Demos