Perceptual control theory: Difference between revisions

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A key insight of PCT is that the controlled variable is not the output of the system (the behavioral actions), but its input, that is, a sensed and transformed function of some state of the environment that the control system's output can affect. Because these sensed and transformed inputs may appear as consciously perceived aspects of the environment, Powers labelled the controlled variable "perception". The theory came to be known as "Perceptual Control Theory" or PCT rather than "Control Theory Applied to Psychology" because control theorists often assert or assume that it is the system's output that is controlled.<ref name=Astrom>{{cite book | last1 =Astrom | first1 =Karl J. | last2 =Murray | first2 =Richard M. | title =Feedback Systems: An Introduction for Scientists and Engineers | publisher =Princeton University Press | date =2008 | url =http://www.cds.caltech.edu/~murray/books/AM08/pdf/am08-complete_28Sep12.pdf | isbn =978-0-691-13576-2 }}</ref> In PCT it is the internal representation of the state of some variable in the environment—a "perception" in everyday language—that is controlled.<ref>For additional information about the history of PCT, see:

* [http://www.pctweb.org/BillPowersAudioInterview1.mp3 Interview with William T. Powers on origin and history of PCT (Part One – 20060722 (58.7M)]

* [http://www.pctweb.org/BillPowersAudioInterview2.mp3 Interview with William T. Powers on origin and history of PCT (Part Two – 20070728 (57.7M)]</ref> The basic principles of PCT were first published by Powers, Clark, and MacFarland as a "general feedback theory of behavior" in 1960,<ref name=PCM1960>{{cite journal | last1 =Powers | first1 =William T. | last2 =Clark | first2 =R.K. | last3 =McFarland | first3 =R.L. | title =A general feedback theory of human behavior (Part I) | journal =Perceptual and Motor Skills | volume =11 | issue =1 | pages =71–88 | date =1960 | doi = 10.2466/pms.1960.11.1.71| s2cid =145256548 }} and {{cite journal | last1 =Powers | first1 =William T. | last2 =Clark | first2 =R.K. | last3 =McFarland | first3 =R.L. | title =A general feedback theory of human behavior (Part II) | journal =Perceptual and Motor Skills | volume =11 | issue =3 | pages =309–323 | date =1960 | doi = 10.2466/pms.1960.11.3.309| s2cid =220712715 }} [Reprinted in {{citation | last1 =Bertalanffy | first1 =Ludwig von | last2 =Rapoport | first2 =Anatol | title =General Systems: Yearbook of the Society for General Systems Research | place =Ann Arbor, Michigan | publisher =Society for General Systems Research | volume =5 | year =1960 }}, pages 63-73, 75-83. Partial reprint in {{cite book | last =Smith | first =A. G. | title =Communication and Culture | publisher =Holt, Rinehart, and Winston | date =1966 | ___location =New York | url =https://archive.org/details/communicationcul00smit| url-access =registration }}]</ref> with credits to cybernetic authors [[Norbert Wiener|Wiener]] and [[William Ross Ashby|Ashby]],. andIt has been systematically developed since then in the research community that has gathered around it.<ref>[http://www.pctresources.com/ Archives of the Control Systems Group (CSG)], also in the [http://discourse.iapct.org/ IAPCT Discourse forum].</ref> Initially, it was overshadowed by the promises[[cognitive ofrevolution]] the(later supplanted by '[[Cognitivecognitive revolutionscience]]'), but has now become better known.<ref name="Marken2009rev" /><ref name=Mansell2011>{{cite journal | last =Mansell | first =Warren | title =Control of perception should be operationalized as a fundamental property of the nervous system | journal =Topics in Cognitive Science | volume =3 | issue =2 | pages =257–261 | date =2011 | doi =10.1111/j.1756-8765.2011.01140.x | pmid =25164294 }}</ref><ref name=Mansell.Carey.revolution>{{cite journal | last1 =Mansell | first1 =Warren | last2 =Carey | first2 =Timothy A. | title =A perceptual control revolution? | journal =The Psychologist | publisher =The British Psychological Society | date =28 November 2015 | url =https://thepsychologist.bps.org.uk/volume-28/november-2015/perceptual-control-revolution | access-date =17 July 2016 }}</ref><ref>{{cite book |date=2020 |editor-last=Mansell |editor-first=Warren |title=The Interdisciplinary Handbook of Perceptual Control Theory: Living Control Systems IV |___location=Cambridge |publisher=Academic Press |doi= |isbn=978-0128189481 }}</ref>

Powers and other researchers in the field point to problems of purpose, causation, and teleology at the foundations of psychology which control theory resolves.<ref>{{cite journal |last1=Powers |first1=William T. |date=1978 |title=Quantitative analysis of purposive systems: Some spadework at the foundations of scientific psychology |journal=Psychological Review |volume=85 |issue=5 |pages=417–435 |doi=10.1037/0033-295X.85.5.417 }}</ref> From [[Aristotle]] through [[William James]] and [[John Dewey]] it has been recognized that behavior is purposeful and not merely reactive, but how to account for this has been problematic because the only evidence for intentions was subjective. As Powers pointed out, behaviorists following [[Wilhelm Wundt|Wundt]], [[Edward Thorndike|ThorndykeThorndike]], [[John B. Watson|Watson]], and others rejected introspective reports as data for an objective science of psychology. Only observable behavior could be admitted as data.<ref>"The behaviorist asks: Why don't we make what we can observe the real field of psychology? Let us limit ourselves to things that can be observed, and formulate laws concerning only those things. Now what can we observe? We can observe behavior—what the organism does or says." Watson, J.B. (1924). ''Behaviorism''. New York: People's Institute Publishing Company.</ref> There follows from this stance the assumption that environmental events (stimuli) cause behavioral actions (responses). This assumption persists in [[cognitive psychology]], which interposes [[cognitive maps]] and other postulated [[information processing]] between stimulus and response, but otherwise retains the assumption of linear causation from environment to behavior.<ref name=Marken2009rev>{{cite journal | last =Marken | first =Richard S. | title =You say you had a revolution: Methodological foundations of closed-loop psychology | journal =Review of General Psychology | volume =13 | issue =2 | pages =137–145 | date =June 2009 | doi =10.1037/a0015106 | s2cid =145458091 }}</ref>

Another, more specific reason that Powers observed for psychologists' rejecting notions of purpose or intention was that they could not see how a goal (a state that did not yet exist) could cause the behavior that led to it. PCT resolves these philosophical arguments about [[teleology]] because it provides a model of the functioning of organisms in which purpose has objective status without recourse to [[introspection]], and in which causation is circular around [[feedback loops]].<ref name=Runkel-PLT>{{cite book | last =Runkel | first =Philip J. | title =People as living things | publisher =Living Control Systems Publishing | date =2003 | ___location =Hayward, CA | isbn =978-0-9740155-0-7 }}</ref>