Behaviorism and Feedback Control

Behaviorism and Feedback Control Author(s): William M. Baum, Hayne W. Reese and William T. Powers Source: Science, New Series, Vol. 181, No. 4105 (Sep. 21, 1973), pp. 1114+1116+1118-1120 Published by: American Association for the Advancement of Science Stable URL: http://www.jstor.org/stable/1736532 . Accessed: 16/01/2014 19:24 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp

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LETTERS

Behaviorism

and Feedback Control

Although there is much of value in the article "Feedback: Beyond beDNA Hybrid Molecules haviorism" by W. T. Powers (26 Jan., Those in attendance at the 1973 p. 351), it is based on an outdated and misconceived idea of behaviorism. Gordon Conference on Nucleic Acids Behaviorism consists in the view that voted to send the following letter to a scientific psychology must deal with Philip Handler, president of the National Academy of Sciences, and to the observable. From this proposition, it follows that psychology should be a John R. Hogness, president of the National Institute of Medicine. A major- science of behavior, and that explanaity also desired to publicize the letter tions of observed phenomena should be couched in the same terms as the obmore widely. servations themselves, rather than inWe are writing to you, on behalf of a voking imagined autonomous entities number of scientists, to communicate a ("explanatory fictions") as causes. matter of deep concern. Several of the most, psychologists toscientific reports presented at this year's Many, perhaps Gordon Research Conference on Nucleic day are behaviorists. Since its points are mainly methodoAcids (June 11-15, 1973, New Hampton, New Hampshire) indicated that we pres- logical, behaviorism never has been ently have the technical ability to join wedded to any particular conception together, covalently, DNA molecules from of behavior. Early behaviorists perhaps diverse sources. Scientific developments over the past two years make it both held views similar to the one Powers reasonable and convenient to generate criticizes, but the inadequacy of deoverlapping sequence homologies at the scribing behavior in terms of responses termini of different DNA molecules. The to stimuli was recognized over 30 years sequence homologies can then be used With the that behavior ago. recognition to combine the molecules by WatsonCrick hydrogen bonding. Application of is affected by its consequences (the existing methods permits subsequent co- Law of Effect), open-loop descriptions valent linkage of such molecules. This began to pass away. Few behaviorists technique could be used, for example, to would disagree with Powers's combine DNA from animal viruses with today bacterial DNA, or DNA's of different statement, "there can be no nontrivial viral origin might be so joined. In this description of responses to stimuli that way new kinds of hybrid plasmids or leaves out purposes." Emphasis on purviruses, with biological activity of unpre- pose, in fact, has been the hallmark of dictable nature, may eventually be created. modern behaviorists' thinking (1). The These experiments offer exciting and inbehaviorists' solution to the problem both for teresting potential advancing knowledge of fundamental biological pro- of purpose has been exactly the one cesses and for alleviation of human health suggested by Powers-selection by conproblems. sequences. That behavior and conseCertain such hybrid molecules may quences constitute a feedback system prove hazardous to laboratory workers is taken as a basic It is (2). premise and to the public. Although no hazard has yet been established, prudence suggests presented this way in at least one elethat the potential hazard be seriously con- mentary text (3). sidered. Powers covers familiar ground in A majority of those attending the Con- two other points. In his discussion of ference voted to communicate their con- acts and results, he actually reinvents cern in this matter to you and to the President of the Institute of Medicine (to Skinner's concept of the operant (4). whom this letter is also being sent). The One of Skinner's most important inconferees suggested that the Academies novations was this conception of a unit establish a study committee to consider of behavior consisting of the class of this problem and to recommend specific actions or guidelines, should that seem responses (Powers's "acts") defined by its environmental effect (Powers's appropriate. Related problems such as the risks involved in current large-scale prep- "result"). As Herrnstein has pointed aration of animal viruses might also be out (1), Skinner's approach to the considered. problem of purpose was to define beMAXINE SINGER havior in terms of its consequences. Room 9N-119, Building 10, Also familiar is the notion of the hierNational Institutes of Health, archical organization of behavior. Bethesda, Maryland 20014 Lashley (5) made the earliest clear DIETER SOLL statement of this view. He argued, as does Powers, for a hierarchy of goals Department of Molecular Biophysics and Biochemistry, and subgoals in behavior. It seemed the Yale University, only way to account for organized New Haven, Connecticut 06520 sequences. Guidelines for

Although Powers's attack on behaviorism is misguided, and many of his ideas have been set down before, nevertheless the constructive aspects of the article deserve praise. The very lack of novelty itself shows that Powers, albeit unwittingly, is square in the mainstream of modern behaviorists' thinking about instrumental behavior. His discussion of feedback, therefore, is most welcome, because it helps define the direction in which we are moving. WILLIAMM. BAUM Department of Psychology, Harvard University, Cambridge, Massachusetts 02138 References and Notes 1. R. J. Herrnstein, introduction to J. B. Watson, Behavior (Holt, Rinehart, and Winston, New York, 1967). 2. The opening sentence of Schedules of Reinforcement by C. B. Ferster and B. F. Skinner (Appleton-Century-Crofts, New York, 1957) reads, "When an organism acts upon the environment in which it lives, it changes that environment in ways which often affect the organism itself." 3. H. Rachlin, Introduction to Modern Behaviorism (Freeman, San Francisco, 1970). See also D. J. McFarland, Feedback Mechanisms in Animal Behaviour (Academic Press, London, 1971) and P. van Sommers, The Biology of Behaviour (Wiley, Sydney, 1972). 4. B. F. Skinner, The Behavior of Organisms (Appleton-Century-Crofts, New York, 1938). See J. R. Millenson, Principles of Behavioral Analysis (Macmillan, New York, 1967) for a treatment in terms of set theory. 5. K. S. Lashley, in Cerebral Mechanisms in Behavior, L. A. Jeffress, Ed. (Wiley, New York, 1951), p. 112.

Powers briefly describes a closedloop feedback model of behavior, with special reference to purposive behavior. The model is of interest and deserves serious consideration as an alternative to other behavioral models, but there are some points about the presentation that warrant critical comment. First, as a model, the system can do no more than represent the phenomena in the domain encompassed. A model (of the type under consideration here) provides no explanations, except in the sense of intuition or analogy. Powers does not describe the theory to be associated with the model, and therefore no real explanations are provided. Second, Powers asserts that no behavioristic model has been able to account for purpose; but in fact purpose has been adequately derived from such behavioristic constructs as the conditioned goal response (the fractional anticipatory goal response, rg) and other mediational response. In Powers's system, "purpose" is like a template; its effect is not goal-seeking behavior but goal-maintaining behavior, and it is concurrently represented in


the system. Powers does not provide explanatory,(ii) is not the only mechadequate, empirically based definitions anistic model that provides a derivation of the key concepts, such as "reference of purpose, and (iii) does not in-

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signal," and in this sense his model is nonbehavioristic. Nevertheless, as far as one can determine, the model is

trinsically preclude conditioning.

mechanistic, in that the components of the feedback loop are analyzed as a unidirectional, linear causal chain. The very fact that the components can be

Department of Psychology, West Virginia University, Morgantown 26506

analyzed in this way indicates that

I. H. W. Ree/ieand W. F. Overton, in Life-Span Research and Psychology: Developmental P. 1970); B. Baltes, R. Gaulet Theory, L. Press, 115pp. Eds. York, New and (Academic 145; W. F. Overton and H. W. Reese, in Life-Span Developmental Psychology: Methodological Issues, J. R. Nesseiroade and H. W. Reese, Eds. (Academic Press, New York, 1973), pp. 65-86; W. F. Overton, Hum. Develop., in press; L. von Bertalanify, General System Theory (Braziller, New York, 1968). 2. H. M. Rosenfeld and D. M. Baer, Psychol.

there is no dialectic interpenetration, or reciprocal interaction, because in such interactions the components are inseparable from the whole or structure that comprises them (1). Powers concludes that "Behavior itself is seen in terms of this model to be self-determined in a specific and significant sense that calls into

HAYNE W. REESE

References

The comments by Baum and Reese

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to approach my control-system the ultimateoffeasibility doubtconditioning serious the most behavior are human on understanding of operant beings." Were it not for the ambiguity balanced I have received from beof the meaning of "ultimate feasibility,"

haviorists. I thank them for trying to

one could reject the statement on empirical grounds. The research literature is replete with studies demonstrating operant conditioningin human subjects

find a place for my work within behaviorism,an attempt that reflects generosity, but not understanding,of what I said (or tried to say). The conceptual

by human experimenters,in some cases being aware even subjects' without (2). One can subjects were that theythe also, in any case, question the state-

basisof control-systemtheory i so alien can to no behavioristic thought that there best be such easy reconciliation.The we can hope for is a constructivecon-

this meaninghas no implication of free will. In the model, "organismsare self-

which to him means behavior. Behavior, however, is not something self-

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determinedin terms of inner control evident that anyone can see just by of what they sense, at every level of looking. What is the behavior of a organizationexcept the highest level." man walking? Is he really tensing his control refers to feedback leg muscles, moving his legs, walking, ("error signal") regardingthe discrep- going to buy a paper, on his way to

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specific "effector functions," or responses. That is, the responses are completely determined by the error signal (and, perhaps, by the state of the system), and the error signal is com-

havior of the nervous system consists

pletely determined by the reference signal and sensor signal. As the sensor signal is determined by the environment, any variability in self-determination must come from variability in

of that output 'becomemore and more mixed with properties of any events in the external physical environment,

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reference signals. Their source is not

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or goal, and the "sensor signal," or in- or maintaining his self-respect? The put. As the model is mechanistic, the point of view of the observer defines error signal will inexorably produce the 'behaviorhe sees. The actual beonly of sending neural signals to musdes and glands; that is the last event that 'trulyreflects the system's output. From that point outward, the results

so that even such elementary behavior

as a "movement"no longer is a unique

indicator of a particular activity in specified in the model (except at the the nervous system. Thus, while Baum's highest level, at which they are as- pronouncement seems reasonable on sumed to be biogeneticallydetermined), the surface, it ignores one of the The model does not demand a reference signal that prohibits operant conditioning; this reference signal was introduced ex hypothesi and is not entailed

deepest conceptual dilemmas of behaviorism. The control-system model shows that behavior at any level, as well as its

by the model. In summary, the model (i) is not

relationshipto "stimulusevents,"makes sense as soon as one recognizes the


concept of the controlled quantity. To

find the proper definition of the controlled quantity, the observer must recognize that his own point of view determines the behavior he will observe, and he must find an objective way to discover the right point of view -namely, that of the behaving system. The observermust try to find out which of the infinity of potential controlled quantities is the one that the behaving system is actually sensing and controlling. Only when the controlled quantity has been correctly identified can the observer see that the system's outputs are always such as to counter the effects which environmental disturbanceswould otherwise have on the controlled quantity. In my article I presented an experimental paradigm, OrK new to psychology, for testing hy48 CIIRRR.IR at potheses concerning the controlled chromato extra 'ions, column screenin Somple Ooncentranew .Brinkmann's quantity and its reference level. upto 4 evapo-.,nraphy,liquidscintillation manyother torSO/48accommodotes In the section on controlled quantirationtubesin a stainlesssteel rack,elimi- proce res. write Brinkrnonnlnstru- ties in my article, there appears an 'FoKiteroture notingharidlin.f indMduolsomples. isby mensof heat ments,.onfidgue Rd.,Westbury,N.Y. .oncentrcdion h(o), which approximation,g(d) says that the cause-effect relationships vdihonaircurrent.' 'i5I.'ThGaa a, rite: rjnkmannlnstruan vacuum,&cnb1ned

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between that canand be observed nervous of stimulus events consequences

system outputs-responses-are expressible wholly in terms of the physics of the local environment, containing al'most no information about the behaving system at all. I see no way in which behaviorism can survive a full understanding of the derivation and signifiIf harmless expression. cance of this theory does indeed decontrol-system scribe correctly the relationship between organisms and their environments, behaviorism has been in the grip of a powerful illusion since its It is therefore not possible that 'beconceptual bases were laid. haviorismalready contains an adequate

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treatment of feedback phenomena; if it did, a behaviorist would have dis-

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covered this illusion already. Many behaviorists have observed feedback phenomena, but they have tried to

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deal with them by translating the terminology of control-system theory well-accepted way that would in such a principles remain behavioristic undisturbed.That is why "purpose" has

purof inner meaningand lost has been poseitsororiginal intentionality, redefined as consequences. That re-

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physical system 'that could contain inner purposes-their telephone-switchboard model had no place for them, and control-system theory then lay far in the foreseeable future. In control-system terms, a purpose

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is not a consequence of behavior, but a model inside the organism for what it wants the perceptual consequences of its outputs (modified by environmental disturbances or not) to be. When I bowl, my inner purpose is to perceive all the pins falling on the first ball. What I perceive is generally something different. 1 am still doing my best to alter my outputs in such a way as to reduce the error between what I generally perceive and what I intend to perceive. Another observer can discover that intended perception by manipulatingmy environment until he finds the state where I cease to alter my outputs in opposition to the changes he causes. There is nothing metaphysical or conjectural about this process. But it does not make any sense in behavioristicterms, because it is designed around rigorous laws of feedback, not around 'the imprecise usages of the term feedback that are found in behaviorism. There seems to be a general impression that feedback is analyzable (in Reese's terms) by following a "unidirectional,linear causal chain around and around a closed circle (I trust that Reese noticed that the circle is closed). That approach to feedback, often expressed as taking into account the effects of a response on subsequent stimuli, is the natural one, but, as every beginning control-systemengineer soon discovers, it leads to totally incorrect predictions of the behavior of the system 'being modeled. The qualitative chain-of-eventsapproachleaves out the crucial factor of system dynamics; when that is properly taken into account, throughuse of a physical analysis of the system and its environment and applicationof differentialequations or transformmethods, a very different and surprisingpicture emerges. If the control system one wants to model is free of spontaneous,self-sustainedoscillations (as normal 'behavioralsystems can safely are), time lags in the system be ignored, and the behavior of the whole system can be seen quite correetly as occurring simultaneously with disturbances.The output changes along with the disturbance(a normal, slowly varying disturbance), and the input variable being monitored continually tracks the inner reference signal, if a variable inner reference signal exists, There are no loopholes in this analysis; if organisms are in the negative feedback relationship with their environ'ments, this is how they behave. To arrive at a different conclusion, one would have to show that the bases of

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